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Signaling Receptors for TGF-b Family Members

Carl-Henrik Heldin1 and Aristidis Moustakas1,2

1Ludwig Institute for Cancer Research Ltd., Science for Life Laboratory, Uppsala University, SE-751 24 Uppsala, Sweden 2Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, SE-751 23 Uppsala, Sweden Correspondence: [email protected]

Transforming b (TGF-b) family members signal via heterotetrameric complexes of type I and type II dual specificity receptors. The activation and stability of the receptors are controlled by posttranslational modifications, such as , ubiq- uitylation, sumoylation, and neddylation, as well as by interaction with other at the cell surface and in the cytoplasm. Activation of TGF-b receptors induces signaling via formation of Smad complexes that are translocated to the nucleus where they act as tran- scription factors, as well as via non-Smad pathways, including the Erk1/2, JNK and p38 MAP kinase pathways, and the Src tyrosine kinase, phosphatidylinositol 30-kinase, and Rho GTPases.

he transforming growth factor b (TGF-b) embryonic development and in the regulation Tfamily of cytokine has 33 human of tissue homeostasis, through their abilities to members, encoding TGF-b isoforms, bone regulate cell proliferation, migration, and differ- morphogenetic proteins (BMPs), growth and entiation. Perturbation of signaling by TGF-b differentiation factors (GDFs), activins, inhib- family members is often seen in different dis- ins, , and anti-Mu¨llerian hormone (AMH) eases, including malignancies, inflammatory (Derynck and Miyazono 2008; Moustakas and conditions, and fibrotic conditions. In cancer, Heldin 2009; Massague´ 2012; Wakefield and Hill TGF-b has a complicated role; initially, it is a 2013). The family members are dimeric mole- tumor suppressor because it inhibits prolifera- cules, which in most cases are stabilized by a tion and stimulates , but at later stages disulfide bond. TGF-b family members are syn- of tumorigenesis TGF-b becomes a tumor pro- thesized as large precursors that need to be moter because it induces epithelial–mesenchy- cleaved to liberate the carboxy-terminally locat- mal transition (EMT), which correlates with ed, active molecule. increased invasiveness and metastasis. TGF-b The TGF-b family signaling pathways are also promotes angiogenesis and suppresses the well conserved and emerged with the first ani- immune system, which contributes to the pro- mal species (Huminiecki et al. 2009). TGF-b tumorigenic effects (ten Dijke and Arthur 2007; family members have important roles during Moustakas and Heldin 2009; Massague´ 2012).

Editors: Rik Derynck and Kohei Miyazono Additional Perspectives on The Biology of the TGF-b Family available at www.cshperspectives.org Copyright # 2016 Cold Spring Harbor Laboratory Press; all rights reserved Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a022053

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C.-H. Heldin and A. Moustakas

RECEPTORS FOR TGF-b FAMILY Binding of a TGF-b family member induces MEMBERS assembly of a heterotetrameric complex of two type I and two type II receptors. There are seven TGF-b family members signal via binding to human type I receptors and five type II recep- dual specificity kinase receptors at the surface tors; individual members of the TGF-b family of target cells. Members of this family of recep- bind to characteristic combinations of type tors have structural characteristics similar to I and type II receptors (Fig. 1). The receptors both / and tyrosine ; al- have rather small cysteine-rich extracellular do- though the family is most often referred to as mains, a transmembrane domain, a juxtamem- serine/threonine kinase receptors, they are in brane domain, and a kinase domain; however, fact dual specificity kinases (Lawler et al. 1997; except for the BMP type II and in con- Manning et al. 2002). This family is rather small trast to tyrosine kinase receptors, the parts car- in mammals, with only 12 members, in contrast boxy terminal of the kinase domains are very to the 58-member family of tyrosine kinase re- short. Ligand-induced oligomerization of type I ceptors (Heldin et al. 2014). In contrast, plants and type II receptors promotes type II receptor have a large number of different serine/threo- phosphorylation of the type I receptor in a re- nine kinase receptors (Champion et al. 2004). gion of the juxtamembrane domain that is rich

TGF-β1 TGF-β2 RI TGF-β3 RII ActivinbA β β T RI/ALK-5 ActivinbB T RII GDF-1 GDF-3 ActRIB/ALK-4 Nodal BMP-3b (GDF-10) ActRII ActRIC/ALK-7 GDF-11 GDF-8 () ActRL1/ALK-1 GDF-9a ActRIIB GDF-9b (BMP-15) ActRIA/ALK-2 BMP-9 BMP-10 BMP-2 BMPRIA/ALK-3 BMP-4 GDF-5 BMPRII GDF-6 GDF-7 BMPRIB/ALK-6 BMP-5 BMP-6 BMP-7 BMP-8A BMP-8B GDF-15 AMHRII AMH

Figure 1. Schematic illustration of the selective binding of members of the transforming growth factor b (TGF-b) family to type I and type II serine/threonine kinase receptors.

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TGF-b Family Receptors

in glycine and serine residues (GS domain), The notion that TGF-b binding induces causing activation of its kinase. a heterotetrameric complex of two TbRI and The activated type I serine/threonine kinase two TbRII molecules was initially supported receptors in turn phosphorylate members of by studies using differential receptor tagging the receptor-activated (R)-Smad family; thus, (Moustakas et al. 1993; Henis et al. 1994; Wells TGF-b, activin, and nodal generally induce et al. 1999), two-dimensional gel electrophoresis phosphorylation of Smad2 and 3, whereas (Yamashita et al. 1994), and genetic comple- BMPs generally phosphorylate Smad1, 5, and 8 mentation (Weis-Garcia and Massague´ 1996). (Feng and Derynck 2005). Activated R-Smads More recently, structural studies have shown then form trimeric complexes with the common that one dimeric TGF-b molecule binds to two mediator Smad4, which are translocated to the TbRI and two TbRII molecules forming a sym- nucleus where they cooperate with other tran- metric 2:2:2 complex. The TGF-b molecule scription factors, coactivators, and corepressors resembles two hand-like structures that are as- to regulate the expression of specific genes. sembled in an antiparallel manner and are held There are also non-Smad signaling pathways together by a disulfide bond in the “wrist” re- activated by TGF-b family members, including gion. TGF-b contacts TbRIwith the “fingertips” the Erk1/2, JNK, and p38 MAP kinase pathways, and TbRII with the underside of the fingers the tyrosine kinase Src, phosphatidylinositol-30 (Hart et al. 2002; Groppe et al. 2008; Radaev (PI3)-kinase, and Rho GTPases (Moustakas and et al. 2010). In addition, direct receptor–recep- Heldin 2005). tor interactions contribute to enhanced stability The present communication focuses on the of the receptor–ligand complex (Radaev et al. structural and functional characteristics of the 2010). type I and type II signaling TGF-b receptors TGF-b1 and TGF-b3 bind TbRII with high- (Fig. 2); however, where appropriate, we will er affinity than TbRI. Thus, the binding occurs include discussions of other members of this first to TbRII; thereafter, TbRI is recruited serine/threonine kinase receptor family. to the complex by recognizing a unique inter- face generated by the TGF-b–TbRII complex (Groppe et al. 2008). In contrast, TGF-b 2 shows TGF-b SIGNALS VIA A HETEROTETRAMERIC rather low affinity to TbRII; thus, preformed TbRI†TbRII COMPLEX TbRII–TbRI heteromeric complexes or co- The three TGF-b isoforms, TGF-b1, TGF-b2, receptors, such as betaglycan, assist TGF-b2 and TGF-b3, bind to a single type II receptor into assembling stable receptor complexes (see (TbRII). However, in addition to the ubiqui- further below). tously expressed type I receptor (TbRI, also The symmetry of the complex between called -like kinase 5 or ALK-5), TGF-b and its receptors suggests that the two there is another type I receptor for TGF-b, called pairs of TbRI†TbRII may signal as independent ALK-1 that is more selectively expressed (e.g., in units. This assumption was proven correct using endothelial cells) (Goumans et al. 2003). a mutant TGF-b3 molecule in which one TGF- Before ligand binding, TbRI and TbRII oc- b protomer had been mutated to prevent recep- cur as monomers, homodimers, and hetero- tor binding; the remaining wild-type half of the dimers; ligand binding stabilizes a heterotetra- TGF-b3 molecule was still able to assemble a meric structure (Chen and Derynck 1994; Henis TbRI†TbRII complex and to induce signaling et al. 1994; Gilboa et al. 1998; Zhang et al. 2009a; with one-quarter to one-half the activity of Ehrlich et al. 2012). The heterodimeric and wild-type TGF-b3 (Huang et al. 2011). TbRII homodimeric interactions are stabilized BMP receptors bind their ligands in similar by contacts between specific epitopes in the cy- symmetric 2:2:2 complexes; but in these com- toplasmic parts of the receptors, whereas the cy- plexes, the type I receptors have higher affinities toplasmic part of TbRI is dispensable for TbRI for the ligand than the type II receptors (Kirsch homodimerization (Rechtman et al. 2009). et al. 2000; Sebald et al. 2004). The ligands for

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C.-H. Heldin and A. Moustakas

N-ter TβRI TβRII

N-ter

ADAM17

γ-Secretase

Ub S165 P Ub T186 P Ub GS S187 P Ub domain S189 P S191 P

S213 P Ub (+) Auto Ub L45 loop Ub Auto Y259 P Ub Kinase Src Y284 P Kinase domain Auto Y336 P domain (+) Auto S409 P S387 (–) Auto S416 P K389 Su Auto Y424 P Src/auto Y470 P L529 F538 Basolateral membrane- targeting motif C-ter Ne K556 Ne K567 Ne Ne C-ter

Figure 2. Schematic illustration of the characteristics of TbRI and TbRII. Structural motifs, as well as post- translationally modified residues and proteolytic cleavage sites are indicated. Green chains of circles, N-linked glycosylations; black circles with white P, phosphorylation sites (auto, receptor autophosphorylation; other kinases indicated: þ or 2 symbols indicate positive or negative impact on receptor kinase activity); gray circles with green Ub, ubiquitin chains (the exact locations of the acceptor lysines are not known); gray circles with purple Su, sumoylation sites; gray circles with blue Ne, neddylation sites. Ubiquitin and NEDD8 are shown as polymeric chains, whereas sumo is illustrated by a monomer, in accordance with the knowledge about these modifications. TbRI is also autophosphorylated on serine/threonine and tyrosine residues, but their exact locations are not known (not shown). Binding of the adaptor Shc to a specific phosphotyrosine is also indicated. N-ter, Amino terminal; C-ter, carboxy terminal.

the BMP receptors bind to the receptor complex domain interactions for the BMP and TGF-b with relatively lower affinity than the corre- receptors also support the model of preformed sponding affinities of TGF-b1 and its receptors heterotetrameric receptor complexes that local- (Sebald et al. 2004). This leads to a greater flex- ize on the cell surface before ligand binding ibility by which BMPs can signal using a more (Ehrlich et al. 2012). Coreceptors, as discussed diverse set of cell-surface receptors (Fig. 1). As later, or other cytoplasmic scaffolding proteins in the case for TbRII, heterotetrameric BMP may facilitate the formation of these complexes. receptor complexes are stabilized by interac- However, we need to view this model with cer- tions between the cytoplasmic domains of the tain caution, as it has mainly been analyzed in receptors (Nohe et al. 2002). Such cytoplasmic cells that express high levels of transfected re-

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ceptors. The interesting possibility that pre- phorylation of Tyr284 has been shown to pro- formed receptor complexes induce signaling mote binding of the adaptors Shc and Grb2; events, which may differ from those of ligand- Grb2 forms a complex with Sos1, a nucleotide induced receptor complexes (Nohe et al. 2002), exchange factor for Ras, which in turn activates requires further rigorous analysis focusing on the Erk1/2 MAP kinase pathway. Mutation of endogenous receptors, and on receptor signal- Tyr284 was found to lead to decreased growth ing under in vivo conditions. and metastasis of breast cancer cells (Galliher- Beckley and Schiemann 2008). TbRI can be phosphorylated at Ser165 TGF-b RECEPTORS ARE REGULATED in the juxtamembrane domain (Souchelnytskyi BY PHOSPHORYLATION et al. 1996). Interestingly, this phosphorylation The activities of both TbRI and TbRII are modulates TGF-b signaling; growth suppres- regulated by several phosphorylation events sion and matrix production are enhanced after (reviewed by Wrighton et al. 2009a). After li- mutation of Ser165, whereas the proapoptotic gand-induced assembly of the heterotetrameric effect is decreased. TGF-b receptor complex, the constitutively Similar to TbRII, the kinase domain of active TbRII phosphorylates TbRI in the GS TbRI has structural elements similar both to domain, located just upstream of the kinase serine/threonine and tyrosine kinases (Man- domain (Fig. 2) (Wrana et al. 1994). The phos- ning et al. 2002); like TbRII, TbRI has been phorylation occurs on several closely located shown to undergo autophosphorylation on ser- residues (i.e., Thr186, Ser187, Ser189, and ine/threonine residues, as well as on tyrosine Ser191); it appears that no single residue is of residues. The phosphorylated tyrosine resi- crucial importance for activation, but there due(s) form docking site(s) for the adaptor mol- needs to be phosphorylation above a certain ecule Shc via its PTB-domain, followed by its threshold in this area for activation of the phosphorylation and recruitment of the Grb2/ TbRI kinase. The phosphorylation leads to a Sos1 complex, and activation of Ras and the Erk conformational change that causes release of MAP kinase pathway (Lee et al. 2007). the 12 kDa-immunophilin FK506-binding pro- The phosphorylation of TGF-b receptors tein (FKBPI2), which binds to the GS domain has been shown to be counteracted by sever- and inhibits the TbRI kinase (Wang et al. 1996; al phosphatases. Thus, GADD34, a regulatory Chen et al. 1997; Huse et al. 1999). The phos- subunit of the protein phosphatase 1 (PP1) phorylation of the GS domain, furthermore, was found to bind to Smad7, which in turn enhances interaction with R-Smads, which pro- binds to TbRI; the PP1 catalytic activity is there- motes their phosphorylation (Huse et al. 2001). by recruited to T bRI and dephosphorylates the The kinase activity of TbRII is regulated receptor (Shi et al. 2004). In endothelial cells, positively by autophosphorylation at Ser213 PP1a was shown to dephosphorylate ALK-1, and Ser409, and negatively by autophosphory- but not the ubiquitous TbRI, ALK-5 (Valdi- lation at Ser416 (Fig. 2) (Luo and Lodish 1997). marsdo´ttir et al. 2006). The PP2A phosphatase In addition, TbRII can be autophosphorylated is also implicated in TGF-b receptor dephos- on tyrosine residues, including Tyr259, Tyr336, phorylation. Interestingly, the related PP2A and Tyr424, which also may contribute to the subunits Ba and Bd modulate TGF-b signaling regulation of the kinase activity of TbRII (Law- in opposite ways; whereas the Ba subunit en- ler et al. 1997), and by Src at Tyr284 (Galliher hances TGF-b signaling, most likely by stabiliz- and Schiemann 2006, 2007); Tyr470 is also ing TbRI, the Bd subunit suppresses TGF-b sig- phosphorylated, either by Src or autophos- naling, most likely by inhibiting the TbRI kinase phorylated (Chen et al. 2014). The finding that activity (Griswold-Prenner et al. 1998; Petritsch TbRII is tyrosine phosphorylated opens up the et al. 2000; Batut et al. 2008). possibility that it binds SH2- or PTB-domain- The T-cell protein tyrosine phosphatase containing signaling molecules. In fact, phos- (TCPTP) has been found to dephosphory-

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late tyrosine phosphorylated TbRII in kidney invasion and metastasis of Ras transformed epithelial cells (Chen et al. 2014). Integrin a1b1 cells. On the other hand, a missense mutation was needed to recruit TCPTP to TbRII; mice S387Y in TbRI, located close to the sumoylation lacking integrin a1b1 showed impaired TCPTP- site and able to prevent sumoylation, was found mediated dephosphorylation of TbRII, leading to be enriched in breast and head-and-neck to enhanced TGF-b signaling and renal fibrosis. cancer metastases (Chen et al. 1998, 2001). In contrast to the detailed analysis of regu- These seemingly contradictory observations latory phosphorylation and dephosphorylation most likely reflect the complicated role TGF-b mechanisms that control signaling activity by has in tumor progression, involving both tu- TGF-b receptors, similar studies on the BMP mor-suppressive and tumor-promoting effects. receptors still lag behind. It is likely that con- Because polyubiquitylation promotes deg- served serine residues in the juxtamembrane GS radation of TGF-b receptors, capable domain of BMP type I receptors are the accep- of deubiquitylating the receptors would be ex- tors for phosphorylation by the paired BMP pected to enhance TGF-b signaling. Certain type II receptor in the heterotetrameric receptor deubiquitylases have been shown to act on complexes, leading to activation of the type I TGF-b receptors. Using a genome-wide gain- receptor kinase (Miyazono et al. 2010). Further- of-function screen, the ubiquitin-specific prote- more, in Xenopus embryos, the protein phos- ase 4 (USP4) was identified as a strong promoter phatase Dullard associates with the BMP re- of TGF-b signaling by deubiquitylating TbRI ceptor complex, dephosphorylating the BMP (Zhang et al. 2012). Interestingly, the kinase type I receptor BMPRIA/ALK-3, leading to Akt, which is activated downstream of PI3-ki- polyubiquitylation and degradation of BMPRII nase, phosphorylates USP4, and this leads to a (Satow et al. 2006). relocation of the molecule from the nucleus to the cytoplasm and plasma membrane, where it can act on TbRI. Thus, USP4 has an important b TGF- RECEPTORS ARE REGULATED role in the cross talk between TGF-b and Akt BY UBIQUITYLATION, SUMOYLATION, signaling pathways. Using a functional RNAi AND NEDDYLATION screen,USP15was identified as akeycomponent Whereas phosphorylation events are of critical of the TGF-b signaling pathway; USP15 binds to importance to regulate the activities of TGF-b the E3 Smurf2, which is recruited to the receptors, additional control of receptor activi- TGF-b receptors in complex with Smad7 and ties and stabilities are exerted by modifications deubiquitylates TbRI (Eichhorn et al. 2012). In- by ubiquitin and related molecules. terestingly, the USP15 was found to be TGF-b receptors are marked for proteaso- amplified in glioblastoma, breast cancer, and mal degradation by polyubiquitylation via ovarian cancer, suggesting that enhanced TGF- Lys48 in the ubiquitin molecule, performed by b signaling, as a consequence of USP15 overac- E3 of the Smurf family, which are recruit- tivity, promotes progression of these tumors. ed to TbRI in complex with Smad7 (Kavsak USP15 has also been found to deubiquitylate et al. 2000; Ebisawa et al. 2001). The amino monoubiquitylated R-Smads, promoting Smad acid residues in the TGF-b receptors that are activity (Inui etal.2011). Inaddition, USP11has polyubiquitylated have not yet been identified. been shown to deubiquitylate TbRI and to en- Because Smad7 and Smurf2 are induced by hance TGF-b signaling (Al-Salihi et al. 2012). TGF-b stimulation, this constitutes an impor- The stability of TbRII is also controlled tant feedback mechanism. by polyubiquitylation, although the E3 ligase TGF-b stimulation also leads to modifica- involved has not been identified (Atfi et al. tion of TbRI by SUMO groups at Lys389, which 2007). In addition, TbRII was recently shown enhances signaling by promoting Smad phos- to be modified also by the ubiquitin-like mole- phorylation (Fig. 2) (Kang et al. 2008). Muta- cule NEDD8 (neural precursor cell-expressed, tion of Lys389 to an Arg residue led to decreased developmentally down-regulated 8) by the E3

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ligase c-Cbl (Zuo et al. 2013). c-Cbl is known every receptor mRNA in the family has been as a ubiquitin E3 ligase and a negative modu- reported as a target of one or more miRNAs. lator of many tyrosine kinase receptors, but has Regulation of receptor expression by miRNAs been shown to be capable also of neddylating can take place during normal development, the epidermal growth factor (EGF) receptor stem-cell propagation, and differentiation, or (Oved et al. 2006). Neddylation of TbRII at under pathological conditions such as hyper- Lys556 and Lys567 was found to promote endo- tension, cancer, or viral infection. The fact cytosis of the receptor to early endosomes and that a given receptor mRNA in the TGF-b fam- to prevent its endocytosis to -positive ily can be regulated by many miRNAs, and that compartments, thereby inhibiting degradation a given miRNA targets several other mRNAs of TbRII (see further below). Interestingly, a in addition to the given receptor, generates a neddylation-defective c-Cbl mutant was found complex reality of miRNA-mediated posttran- in leukemias, suggesting that TbRII neddylation scriptional control. Here we discuss selected is important to inhibit leukemia progression examples of such miRNAs that provide good (Zuo et al. 2013). examples of the complexity. In the TGF-b path- Our knowledge about ubiquitin-based way, TbRII mRNA is targeted by several mechanisms that regulate BMP receptor func- miRNAs including miR-302 and miR-372, tion remains at a more primitive stage compared which down-regulate the expression of TbRII with TGF-b receptors. Most studies have con- during the protocol of induced pluripotent centrated on the BMPRII, which as described stem-cell generation (Subramanyam et al. above, after dephosphorylation of BMPRIA/ 2011). TbRII down-regulation enhances the de- ALK-3 by the protein phosphatase Dullard, be- differentiation process and promotes a mesen- comes polyubiquitylated and degraded (Satow chymal to epithelial transition that is required et al. 2006). Under pathological conditions, for the establishment of the stem cells in vitro. In such as Kaposi sarcoma and certain lymphomas a different context, miR-302, which is induced caused by infection with the Kaposi sarcoma– by connective tissue growth factor ([CTGF] also associated virus, a virally encoded ubiquitin li- called CCN2), targets TbRII mRNA and thereby gase polyubiquitylates BMPRII and promotes inhibits kidney fibrosis (Faherty et al. 2012). On its lysosomal degradation (Durrington et al. the other hand, during progression of kidney 2010). Under more physiological conditions, fibrosis, TGF-b signaling transcriptionally re- the E3 ubiquitin ligase Itch mediates BMPRII presses the miR-let-7b (commonly known as polyubiquitylation at least in pulmonary endo- let-7b); miR-let-7b targets and down-regulates thelial cells (Durrington et al. 2010). Finally, the TbRI mRNA expression, and, thus, miR-let-7b DUB USP15 that deubiquitylates and stabilizes repression by TGF-b causes TbRI induction TbRI, also deubiquitylates the BMP type I re- and enhanced signaling in kidneys where fibro- ceptor BMPRIA/ALK-3, causing its stabiliza- sis develops (Yang et al. 2013; Wang et al. 2014). tion and enhancement of BMP signaling in vitro In human cancer, the expression of TbRII can and in vivo (Herhaus et al. 2014). Whereas also be down-regulated by miRNAs, such as USP15 targets TbRI by binding to Smad7, miR-17-92 in neuroblastoma and miR-520c USP15 acts on BMPRIA via Smad6, presenting and miR-373 in breast cancer (Mestdagh et al. a conserved mechanism of receptor deubiquity- 2010; Keklikoglou et al. 2012). Critical in hepa- lation via the inhibitory (I)-Smads (Eichhorn tocellular carcinoma progression is the down- et al. 2012; Herhaus et al. 2014). regulation of TbRI/ALK-5 expression by miR- 140-5p (Yang et al. 2013; Wang et al. 2014). Early frog development is specified by nodal CONTROL OF TGF-b RECEPTOR signaling, and the spatial restriction of the em- EXPRESSION BY microRNAs bryonic cells that respond to nodal is regulated The levels of TGF-b receptors are negatively by two members of the miR-15 family, miR-15 controlled by microRNAs (miRNAs). Almost and miR-16, which target the ActRII receptor

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mRNA (Martello et al. 2007). The expression that limits the extent of BMPRII signaling of the same type II receptor can be down-regu- in developing neurons (Sun et al. 2013). Artery lated by miR-181a in granulosa cells of the ova- stenosis depends on vascular smooth muscle ry, which differentiate in response to activin cell proliferation, which is prohibited by BMP (Zhang et al. 2013b); activin signaling represses signaling and promoted by TGF-b; TGF-b miR-181a expression so that its type II receptor causes miR-17 up-regulation during stenosis, can be expressed at significant levels that pro- which down-regulates BMPRII expression and mote granulosa cell differentiation. The ex- releases the cells from the antiproliferative BMP pression of the second activin type II receptor, control (Luo et al. 2014). During the develop- ActRIIB, is controlled by five miRNAs in the ment of pulmonary arterial hypertension context of normal kidney homeostasis, whereas (PAH), interleukin-6 signaling via STAT3 up- kidney neoplasia in young children is character- regulates the miR-17 cluster and causes BMPRII ized by down-regulation of miR-141, miR-192, down-regulation, a hallmark of this pathologi- miR-194, miR-200c, and miR-215, and conse- cal condition (Brock et al. 2009). Alternatively, quent up-regulation of ActRIIB in the develop- BMPRII expression can also be down-regulated ing nephroblastomas (Senanayake et al. 2012). by miR-21 during PAH (Parikh et al. 2012). The expression of activin/nodal type I recep- miRNAs are also involved in control of tors ActRIB/ALK-4 and ActRIC/ALK-7 is also TGF-b signaling in malignancies. In glioma, negatively regulated by miRNAs; in normal BMPRII down-regulation is achieved via miR- ovarian granulosa cells, ALK-4 mRNA is target- 135a, whose expression is elevated in this cancer ed by miR-145, which controls cell proliferation (Wu et al. 2012). In the same tumor type, (Yan et al. 2012). During erythropoiesis, the miR-656 targets BMPRIA/ALK-3 mRNA; ALK-4 mRNA is targeted by miR-24; ALK-4 however, expression of miR-656 is frequently down-regulation is required so that early stages down-regulated in human glioma (Guo et al. of erythroid cell differentiation can progress 2014), which is paradoxical based on the estab- (Wang et al. 2008). During breast cancer inva- lished tumor-suppressive role of BMP signaling sion and angiogenesis, the ALK-4 mRNA is in this tumor. On the other hand, BMPRIB/ down-regulated by miR-98; because ALK-4 ALK-6 expression is down-regulated by miR- positively contributes to breast cancer metasta- 125b in breast cancer cells (Saetrom et al. sis, miR-98 acts as a metastasis suppressor (Sira- 2009). Breast cancer patients show allele-specif- gam et al. 2012). Finally, in ovarian cancers, the ic polymorphisms in the 30-untranslated region nodal/ALK-7 tumor suppressor pathway is in- of BMPRIB/ALK-6 mRNA where miR-125b activated by miR-376c, which down-regulates binds, disrupting the down-regulation mecha- the ALK-7 receptor, showing that miR-376c nism and characterizing patients with higher has a protumorigenic effect (Ye et al. 2011). risk for disease progression (Saetrom et al. Interestingly, miR-302, which down-regu- 2009). The same polymorphism has been con- lates TbRII expression, also down-regulates firmed in prostate cancer, which generates a BMPRII expression; BMP-4 signaling represses cancer susceptibility allele (Feng et al. 2012), miR-302 to promote BMPRII expression and whereas in endometriosis, the polymorphic se- signaling in smooth muscle cells of the pulmo- quence of the miR-125b site on the BMPRIB/ nary vasculature (Kang et al. 2012). Osteogen- ALK-6 mRNA correlates with protection from esis induced by BMP signaling in mesenchymal disease progression and an antiproliferative role stem cells depends on BMPRII receptor expres- of the elevated BMPRIB/ALK-6 receptor sig- sion, which is regulated by miR-100 (Zeng et al. naling (Chang et al. 2013). 2012). The miR-17 family is another central The expression of the third BMP type I re- regulator of BMPRII expression in physiological ceptor, ActRIA/ALK-2, is also controlled by and pathological contexts in the brain cortex several miRNAs. In differentiating , (Mao et al. 2014); BMP-2 induces miR-17 fam- miR-30c is up-regulated and silences ALK-2 ex- ily members, forming a negative feedback loop pression (Karbiener et al. 2011); miR-148b and

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TGF-b Family Receptors

miR-365 target the 30-untranslated region of chains are not necessary for TGF-b binding; in ALK-2 mRNA (Mura et al. 2012); down-regu- contrast, large polysaccharide chains may per- lation of ALK-2 mRNA by miR-148a is relevant turb TbRI–TbRII interaction and thus inhibit for the cancer stem-cell population in hepato- TGF-b signaling (Eickelberg et al. 2002). Beta- cellular carcinoma (Li et al. 2015); in the glycan has been shown to promote both Smad liver, BMP signaling is coordinated with the and non-Smad signaling (You et al. 2007). homeostasis of iron; and, after depletion of However, betaglycan binds TbRI and TbRII in- iron levels, miR-130a expression is up-regulated dependently, and overexpression of betaglycan causing ALK-2 silencing and decrease in BMP-6 in MDA-MB-231 cells was found to inhibit signaling, leading to down-regulation of the TGF-b-induced Smad2 and Smad3 phosphory- BMP target gene hepcidin, which produces lation (Tazat et al. 2015). Betaglycan is basolat- the liver hormone that regulates iron homeosta- erally located in polarized breast epithelial cells, sis (Zumbrennen-Bullough et al. 2014). and loss of the basolateral localization promotes All of the above examples underscore the EMT (Meyer et al. 2014). Thus, depending on necessity to understand whether each miRNA expression levels and subcellular localization, regulates the expression of a specific TGF-b betaglycan can promote or suppress TGF-b sig- family receptor only during a specific biological naling. condition, or whether multiple miRNA-based Betaglycan binds all three TGF-b isoforms mechanisms operate in parallel to assure effec- and stabilizes the complex between TbRI and tive cross talk and coordination with other sig- TbRII; this function is particularly important naling pathways. for TGF-b2, which binds to TbRII with rather low affinity. Betaglycan-deficient mouse em- bryo fibroblasts show reduced Smad2 nuclear SIGNALING VIA TGF-b RECEPTORS translocation and reduced growth suppression IS REGULATED BY CORECEPTORS in response to TGF-b2 stimulation, but not in Signaling via TGF-b family member receptors response to TGF-b1 and TGF-b3 (Stenvers et al. is modulated by interactions with other trans- 2003). Betaglycan also binds and promotes sig- membrane proteins and proteins anchored in naling by inhibin (Lewis et al. 2000; Wiater et al. the membrane by glycophosphoinositol (GPI). 2006) and BMPs (Kirkbride et al. 2008; Lee et al. Many of the coreceptors control ligand presen- 2009). tation or availability to the signaling receptor The extracellular domain of betaglycan can kinases. However, some of the coreceptors also be released by proteolytic cleavage; because the mediate signaling by other growth factor recep- soluble extracellular domain retains its TGF-b tors, and may thus act as broader platforms of binding capacity, it acts as a scaffold that in- integration of that has im- hibits TGF-b signaling (Lo´pez-Casillas et al. pacts on diverse pathophysiological conditions. 1994). This process is biologically relevant as betaglycan mutations that inhibit shedding enhance cellular responses to TGF-b; the op- Betaglycan/TbRIII posite experiment with betaglycan mutants Betaglycan (also called type III TGF-b receptor) that show more efficient proteolytic shedding is a transmembrane proteoglycan with both resulted in relative reduction of cellular re- chondroitin sulphate and heparan sulphate sponses to TGF-b (Elderbroom et al. 2014). polysaccharide chains (Lo´pez-Casillas et al. Moreover, betaglycan expression was found to 1991, 1993). The extracellular domain of beta- decrease during breast cancer progression and glycan has two lobular subdomains separated low betaglycan levels correlated to poor prog- by a linker domain; each lobular subdomain nosis; betaglycan appears to inhibit tumor in- separately contributes to ligand binding and vasion by undergoing ectodomain shedding together forms a high-affinity ligand-binding thereby sequestering and inhibiting TGF-b site (Mendoza et al. 2009). The polysaccharide (Dong et al. 2007).

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Betaglycan may have functions that go be- phorylation of Smad1, 5, and 8. also yond presenting the ligand to TbRI and TbRII. binds BMPs and promote their signaling via Knockout of the betaglycan gene results in Smad1, 5, and 8 (Barbara et al. 1999; David embryonic lethality (Stenvers et al. 2003); beta- et al. 2007; Scherner et al. 2007). glycan has been shown to interact with the scaf- Inactivation of the endoglin gene leads to folding protein arrestin and thereby activate defects of the heart and vascular system (Arthur Cdc42 and inhibit cell migration (Mythreye et al. 2000; Sorensen et al. 2003). Interesting- and Blobe 2009) and to promote neuronal dif- ly, loss-of-function mutations in the endoglin ferentiation by interacting with fibroblast gene cause hereditary hemorrhagic telangiecta- growth factor 2 (FGF-2) and FGF receptor 1 sia (HHT) type I (see further below) (McAllis- (Knelson et al. 2013). Betaglycan has also been ter et al. 1994). shown to affect TbRI and TbRII trafficking and signaling (see further below). BMP and Activin Membrane-Bound Inhibitor The transmembrane receptor BMP and activin Endoglin membrane-bound inhibitor (BAMBI) has an Endoglin is expressed preferentially on endo- extracellular domain similar to other type I re- thelial cells and acts as an accessory protein for ceptors, which can bind TGF-b and other TGF-b binding to signaling TGF-b receptors; it members of the TGF-b family, but has only a lacks glycosaminoglycan chains and occurs as a short intracellular domain without enzymatic disulfide-bound dimer (Barbara et al. 1999; activity (Onichtchouk et al. 1999; Grotewold Guerrero-Esteo et al. 2002). Endoglin has been et al. 2001; Loveland et al. 2003). BAMBI is shown to differentially affect TGF-b signaling. believed to act as a negative regulator of BMP Thus, endoglin negatively regulates ALK-5-in- signaling during embryonic development duced Smad2 and Smad3 pathways but posi- (Onichtchouk et al. 1999; Tsang et al. 2000). tively regulates signaling by ALK-1 to Smad1, Because the expression of BAMBI is induced 5, and 8 (Lebrin et al. 2004; Scherner et al. by TGF-b, it may also act in a negative feedback 2007). Phosphorylation of endoglin at Ser646 mechanism in TGF-b signaling (Sekiya et al. and Ser649 by TbRI was shown to be necessary 2004; Xi et al. 2008). Mechanistically, BAMBI for ALK-1-mediated activation of Smad1, 5, and synergizes with Smad7 and inhibits TGF-b sig- 8 in endothelial cells (Ray et al. 2010). naling by forming a ternary complex with TbRI Endoglin occurs as two splice forms, the and Smad7, thereby inhibiting the interaction predominant long (L)-endoglin with a cyto- between TbRI and R-Smads (Yan et al. 2009). plasmic tail of 47 amino acid residues, and a short (S)-endoglin with a cytoplasmic tail of only 14 amino acid residues (Velasco et al. 2008). Interestingly, L-endoglin enhances sig- Cripto, also known as Cripto-1/FRL-1/Cryptic naling via ALK-1 to activate Id1 expression, (EGF–CFC), is a GPI-anchored membrane whereas S-endoglin promotes signaling via protein consisting of an EGF-like and a CFC ALK-5 to induce plasminogen activator inhib- domain. It binds to nodal and specific members itor-1 (PAI-1) expression. The cytoplasmic tail of the GDF family and facilitates ligand inter- of L-endoglin contains a PDZ-binding motif, action with the ALK-4 and ALK-7 receptors with which it interacts with GAIP interacting (Yan et al. 2002). In addition, Cripto directly protein, carboxyl terminus (GIPC), a scaffold- regulates TGF-b signaling in the context of can- ing protein known to regulate cell-surface re- cer as it binds to TGF-b1 and blocks its access ceptor expression and trafficking (Lee et al. to TbRI (Gray et al. 2006). This mechanism can 2008). Through the TGF-b-independent inter- explain the oncogenic action of Cripto, as it action with endoglin, GIPC promotes cell-sur- inhibits cytostatic actions of TGF-b in epithelial face retention of endoglin and enhances phos- cell types. In addition to TGF-b, activing, and

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GDF signaling, Cripto coordinates the signaling naling receptors and negatively regulates TGF-b activities of many other pathways, including signaling (Finnson et al. 2006). CD109 directs members of the EGF receptor family and Wnt the localization of TGF-b receptors to caveolae family, suggesting a more global role of this co- and promotes their degradation (Bizet et al. receptor in diverse biological processes ranging 2011) in a process involving Smad7 and Smurf2 from embryonic development and stem-cell (Bizet et al. 2012). renewal to various pathogenetic processes (Nagaoka et al. 2012). -1

RGMa, RGMb, and RGMc Neuropilin-1 (NRP1) is a transmembrane re- ceptor that, in addition to semaphorins and The repulsive guidance molecule b isoform members of the vascular endothelial cell (RGMb; also called DRAGON) is also a GPI- growth factor family, binds TGF-b (Glinka anchored molecule; it binds BMP-2 and -4 and and Prud’homme 2008). In myofibroblasts facilitates signaling via BMP type II and type I and tumor cells, NRP1 has been shown to sup- receptors (Samad et al. 2005). Studies in renal press Smad1, 5, and 8 phosphorylation, while epithelial cells have revealed the potential of enhancing Smad2 and 3 phosphorylation (Cao RGMb to down-regulate E-cadherin protein ex- et al. 2010; Glinka et al. 2011). However, in pression, a hallmark of the EMTresponse and to endothelial cells, NRP1 decreases Smad2 and 3 induce apoptosis, both being well-established phosphorylation, which suppresses the stalk responses to TGF-b (Liu et al. 2013). Attempts cell phenotype and enhances the tip cell pheno- to link RGMb function to the action of TGF-b type during sprouting angiogenesis (Aspalter have so far not provided positive results (Liu et al. 2015). et al. 2013). The RGMb homolog RGMa also acts as a BMP coreceptor and facilitates the se- lective association of BMP ligands to specific SIGNALING VIA TGF-b RECEPTORS type II receptors, so that high RGMa expression IS MODULATED BY INTERACTIONS selects for ActRII as the signaling receptor of WITH OTHER CELL-SURFACE PROTEINS BMP-2 and BMP-4, whereas low RGMa expres- sion permits the same ligands to select for Signaling by TGF-b family member receptors is BMPRII as their signaling receptor (Xia et al. also modulated by a number of cell-surface pro- 2007). A similar coreceptor function for BMPs teins, which are not genuine coreceptors, be- has been ascribed to RGMc (also known as he- cause they do not affect so much the binding mojuvelin), which amplifies BMP signaling in of ligands to the TGF-b family receptor ectodo- the liver, leading to hepcidin up-regulation and mains, rather they are involved in the assembly a balancing mechanism for overall iron homeo- of multiprotein complexes on the cell surface stasis in the body (Babitt et al. 2006). Accord- leading to cross talk and positive or negative ingly, mutations in the RGMc coreceptor de- regulation of the activities of the signaling re- crease BMP signaling in the liver, resulting in ceptors in the TGF-b family. Some examples are low hepcidin levels and high iron accumulation discussed in the following section. that causes hemochromatosis. Vascular Endothelial Cadherin CD109 Vascular endothelial cadherin (VE-cadherin) The GPI-anchored protein CD109 belongs to is an endothelial-specific adherens junctional the a2-macroglobulin family (Lin et al. 2002) protein that forms complexes with TbRII, and binds TGF-b1 with high affinity and other TbRI/ALK-5, ALK-1, and endoglin and pro- TGF-b isoforms with lower affinity (Tam et al. motes the formation of active signaling receptor 1998). It also forms a complex with TGF-b sig- assemblies, thus promoting all signaling aspects

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of TGF-b in endothelial cells (Rudini et al. remains unclear; however, the cytoplasmic do- 2008). main of CD44 is known to bind Smad1, and thus facilitates BMP-7 signaling during chon- drocyte differentiation (Peterson et al. 2004). Occludin The epithelial tight junctional protein occludin Platelet-Derived Growth Factor b interacts with TbRI and this promotes localiza- tion of active TGF-b receptor complexes to tight In dermal fibroblasts, TbRI forms cell-surface junctions, leading to the rapid disassembly of complexes not only with CD44, but also with these junctions in mammary epithelial cells re- the platelet-derived growth factor b receptor sponding to TGF-b and undergoing EMT (Bar- (PDGFRb) (Porsch et al. 2014). Interestingly, rios-Rodiles et al. 2005). PDGF-BB stimulation promotes activation of latent TGF-b and thus results in a low degree of activation of Smad2 phosphorylation that Integrins promotes fibroblast migration, a hallmark The integrin receptor family member avb3is TGF-b response (Porsch et al. 2014). transcriptionally induced by TGF-b signaling in lung fibroblasts and forms a complex with TrkC TbRII, which facilitates active receptor complex formation and enhances overall signaling by Another that pairs with TGF-b, leading to positive regulation of cell the TGF-b receptors is the neurotrophin recep- proliferation (Scaffidi et al. 2004). In a similar tor TrkC and the related oncogenic, constitu- scenario, blood flow shear stress activates integ- tively active chimeric receptor Tel-TrkC or rin avb3, which pairs with BMPRII via its cy- ETV6-NTRK3 (Jin et al. 2005, 2007c). Both toplasmic domain of the latter receptor, leading ETV6-NTRK3 and TrkC associate with TbRII, to BMP receptor activation and downstream sequester the receptor, and disrupt active com- Smad and Erk1/2 MAP kinase signaling that plex formation with TbRI, thus mediating neg- promotes proliferation of endothelial cells ative control of TGF-b signaling. The oncogenic (Zhou et al. 2013). activities of these receptor tyrosine kinases can therefore be promoted by antagonizing physio- logical TGF-b signaling. The same mechanism CD44 seems to apply to the BMP receptors, as TrkC Similar to the above examples, the hyaluronan binds and phosphorylates the BMPRII cytoplas- receptor CD44, a ubiquitously expressed cell- mic domain causing disruption of the complex surface protein, forms a complex with TbRI, with the BMP type I receptor and suppression of possibly guided by the short cytoplasmic do- BMP signaling in colon cancer cells (Jin et al. main of CD44 that binds to the TbRI juxta- 2007b). However, as TGF-b and BMP signaling membrane domain (Bourguignon et al. 2002). not only suppress but also promote cancer pro- Stimulation of cells with hyaluronan activates gression, mechanistic models of TrkC onco- the CD44–TbRI complex, enhances R-Smad genesis that involve suppression of TGF-b phosphorylation and CD44 tail phosphoryla- receptor signaling should be evaluated with cer- tion by the TbRI, which promotes anchoring tain caution. to the actin cytoskeleton and migratory re- sponses in breast cancer cells (Bourguignon et Ror2 al. 2002). On the other hand, in dermal fibro- blasts, CD44 was found to have a negative role The receptor tyrosine kinase Ror2 forms com- during TGF-b signaling by affecting TGF-b re- plexes with BMPRIB/ALK-6, and activation of ceptor endocytosis (Porsch et al. 2014). Wheth- BMPRIB/ALK-6 by GDF-5 leads to transphos- er BMP receptors form complexes with CD44 phorylation of Ror2, which then silences BMP

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Smad signaling and activates Erk1/2 MAP ki- as a TbRI-interacting protein, which suppresses nase signaling leading to chondrogenic differ- receptor signaling by stabilizing the binding of entiation (Sammar et al. 2004). The mechanism Smad7 to the receptor (Datta et al. 1998; Datta by which Ror2 activation leads to suppression and Moses 2000). STRAP has also been report- of BMP-specific R-Smad phosphorylation re- ed to link the kinase phosphoinositide-depen- quires deeper analysis. The short digits devel- dent kinase 1 (PDK1), which activates Akt, to oped in the inherited family of disorders called TbRI and to promote its activation (Seong et al. brachydactylies are explained by inhibitory mu- 2005), and to bind and inhibit the nucleoside tations that accumulate in any of the three com- diphosphate (NDP) kinase NM23-H1 (Seong ponents of this ligand–receptor complex (i.e., et al. 2007). STRAP thus affects TGF-b signal- GDF-5, BMPRIB/ALK-6, or Ror2), providing ing via several mechanisms. Similarly, Yes-asso- genetic evidence in humans that the heterotypic ciated protein (YAP65) forms complexes with receptor complex may be physiologically im- TbRI and enhances recruitment of Smad7 via portant by controlling chondrogenesis. direct interaction, leading to signaling down- regulation (Ferrigno et al. 2002). An additional negative regulator of TGF- SIGNALING VIA TGF-b RECEPTORS b signaling is the adaptor protein Dapper2 IS MODULATED BY INTERACTIONS (Dpr2), which binds to TbRI and promotes ly- WITH CYTOPLASMIC PROTEINS sosomal degradation of the receptor (Su et al. 2007). This mechanism has developmentally Cytoplasmic Adaptors: FKBP12, STRAP, conserved significance in mouse and zebrafish YAP65, Dapper2, Hsp90, TLP, BAT3, early embryos. and SPSB1 A number of cytoplasmic adaptors and As has been mentioned above, the immunophi- chaperones associate with TGF-b receptors to lin FKBP12 binds to the GS domain of TbRI, promote signaling. The chaperone protein, and thereby pushes the aC helix of the N-lobe Hsp90, binds to TbRII and TbRI and protects of the kinase in an unfavorable position, which them from association with the ubiquitin ligase inhibits the kinase (Huse et al. 1999). It appears Smurf2, thus stabilizing active receptor com- that the kinase in type I receptors of the TGF-b plexes and promoting Smad signaling down- family, in contrast to most other kinases, is con- stream of TGF-b (Wrighton et al. 2008). The stitutively active, and is kept in an inhibited adaptor protein TLP (TRAP-1-like protein) as- form by its association with FKBP12. This sociates with TbRII (and activin receptors) and mechanism is conserved among many type I with Smad4 (Felici et al. 2003). The role of TLP receptors in the TGF-b family as FKBP12 can seems to specify selective activation of Smad2/ also negatively regulate the kinase activities of Smad4 signaling, while bypassing Smad3/ BMPRIA/ALK-3, ActRIA/ALK-2, and ActRLI/ Smad4 signaling. In mesangial cells, the HLA- ALK-1 (Spiekerkoetter et al. 2013). Mutations B-associated transcript 3 (BAT3) adaptor binds in the vicinity of the GS domain of the BMP to TbRI–TbRII complexes and potentiates receptor ActRIA/ALK-2 release the receptor Smad signaling and matrix-related responses from FKBP12 control and cause its constitutive to TGF-b (Kwak et al. 2008). activation, which plays detrimental roles during Spry domain-containing SOCS box protein the pathological transformation of endothelial 1 (SPSB1) binds to TbRII, but not TbRI, via its and mesenchymal progenitor cells to osteo- Spry domain (Liu et al. 2015) and negatively cytes, a characteristic of the congenital syn- modulates TGF-b signaling by recruiting E3- drome, fibrodysplasia ossificans progressiva ligase(s) via its SOCS box, leading to poly- (see further discussion below) (van Dinther ubiquitylation and proteasomal degradation et al. 2010; Chaikuad et al. 2012). of TbRII (Liu et al. 2015). Because SPSB1 is Serine/threonine kinase receptor-associat- induced by TGF-b stimulation, it has a negative ed protein (STRAP) was originally identified feedback role.

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Cytoplasmic Kinases: cGKI and has been established for other signaling pathways, including interferon receptors. The The cyclic guanosine 30,50-monophosphate-de- alternative scenario, which involves cleavage of pendent kinase I (cGKI) associates with and the TbRI cytoplasmic domain and its translo- phosphorylates the BMPRII cytoplasmic do- cation to the nucleus, will be discussed later. main (Schwappacher et al. 2009). On BMPRII activation by ligand binding, cGKI dissociates from the receptor and translocates to the nucle- Transcriptional Cofactors: MED12 and c-Ski us bound to Smad1, assisting in transcriptional MED12 is a component of the transcriptional regulation by the Smad complex. MEDIATOR complex in the nucleus; however, some MED12 molecules reside in the cytoplasm Cytoskeletal and Motor Protein Regulators: and bind to immature forms of TbRII and Rock2, km23-1, and Tctex2b inhibit its glycosylation thereby preventing its cell-surface expression (Huang et al. 2012). The Rho-associated serine/threonine kinase MED12 thus suppresses TGF-b signaling. Rock2, best known for its role in regulation of Knockdown of MED12 was shown to confer cell migration, contraction, and associated cyto- resistance to several kinase inhibitors used as skeletal assembly with cell-adhesion receptors, cancer drugs through enhanced TGF-b signal- negatively regulates TGF-b signaling after as- ing (Huang et al. 2012). sociation with TbRI and priming of receptor c-Ski is another predominantly nuclear pro- degradation in lysosomes (Zhang et al. 2009b). tein that can also be present in the cytoplasm, This mechanism has been shown to be im- where it suppresses TGF-b signaling by binding portant during fish embryogenesis. The motor to TbRI (Ferrand et al. 2010). The interaction protein dynein chain km23-1 has been between c-Ski and TbRI promotes a constitu- shown to bind TbRII and to be phosphorylated tive association of R-Smad/Smad4 complexes after TGF-b stimulation (Tang et al. 2002). to the receptor, whereby their nuclear translo- km23-1 promotes both Smad-dependent (Jin cation is perturbed. c-Ski has also been shown et al. 2007a) and Smad-independent (Jin et al. to suppress TGF-b signaling by repressing the 2012) signaling. In contrast, the motor protein Smad transcriptional activity (Luo 2004); thus, dynein light chain Tctex2b associates with the c-Ski suppresses TGF-b signaling at two differ- short cytoplasmic tail of endoglin in endothelial ent levels. cells and with TbRII and betaglycan in endothe- lial and other cell types, providing negative reg- ulation of TGF-b signaling (Meng et al. 2006). TGF-b SIGNALING IS MODULATED BY FEEDBACK MECHANISMS TGF-b signaling is carefullycontrolled byseveral b SIGNALING VIA TGF- RECEPTORS feedback mechanisms operating at the receptor IS MODULATED BY INTERACTIONS level, as well as upstream and downstream of the WITH NUCLEAR SHUTTLING PROTEINS receptors. The feedback mechanisms operating Although the TGF-b family receptors mainly at the receptor level include TGF-b-induced ex- localize on the plasma membrane and intracel- pression of inhibitory Smad7, which then forms lular membranes (secretory or endocytic vesi- a complex with the ubiquitin ligase Smurf and cles), they have been reported to interact with the PP2C phosphatase; Smad7 binds to TbRI proteins whose best-characterized function is and thus brings Smurf and PP2C close to the exerted in the nucleus. This is topologically fea- receptors, promoting their ubiquitylation and sible as the nuclear proteins shuttle to the cyto- degradation and dephosphorylation and deac- plasm. Regulation of TGF-b family receptor tivation, respectively (Hayashi et al. 1997; Nakao function by nuclear proteins that shuttle to the et al. 1997; Kamiya et al. 2010). The nega- cytoplasm is not unique to the TGF-b receptors tive feedback effect of Smad7 is balanced by

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TGF-b-induced expression of TGF-b-stimu- SIGNALING VIA SMAD AND NON-SMAD lated clone 22 (TSC22), which competes with PATHWAYS Smad7 for binding to TbRI (Yan et al. 2011). Smad7 binds to and inhibits essentially all After TbRII-induced phosphorylation and ac- type I receptors in the TGF-b family, whereas its tivation of TbRI, TbRI phosphorylates Smad2 sister protein Smad6 shows preferential binding and 3 in their carboxy-terminal SSXS motifs and inhibitory activity toward the BMP type I (Abdollah et al. 1997; Souchelnytskyi et al. receptors ALK-3 and ALK-6 (Goto et al. 2007). 1997). Type I receptors for activin and nodal, Both inhibitory Smads cooperate in suppress- ALK-4 and ALK-7, respectively, also phosphor- ing the physiological BMP signaling during dif- ylate Smad2 and 3, whereas the BMP type I re- ferentiation of mesenchymal progenitor cells to ceptors ALK-2, -3, and -6 preferentially phos- (Maeda et al. 2004). This happens phorylate Smad1, 5, and 8. ALK-1 is a type I via a rapid and direct induction of Smad6 ex- receptor for TGF-b, but also binds (e.g., BMP- pression by the primary BMP stimulus, fol- 9 and 10) (David et al. 2007) and phosphory- lowed by activation of autocrine TGF-b signal- lates Smad1, 5, and 8 (Goumans et al. 2003). ing, which then induces a second wave of Smad7 However, the specificity in R-Smad phosphory- expression that, together with the preexisting lation is not absolute, and TGF-b has been Smad6, shuts down BMP receptor activity in a shown to phosphorylate also Smad1 and 5 more sustained manner and limits the rate of (Liu et al. 1998), via TbRI (Liu et al. 2009b; differentiation to osteoblasts (Maeda et al. Wrighton et al. 2009b), or ALK-2 and ALK-3 2004). BMP signaling induces Smad6 expres- (Daly et al. 2008). sion, which then down-regulates the type I re- The epitope in the type I receptors of the ceptors (Ishida et al. 2000). Such receptor family that is responsible for the selectivity is the down-regulation by inhibitory Smads may con- L45 loop of the kinase domain, which binds to tribute to the bulk of type I receptors in the cell. the L3 loop and the adjacent a-helix 1 in the On the other hand, Smad6 has been shown to be carboxy-terminal MH2 domains of Smads methylated by the methyltransferase PRMT1 (Feng and Derynck 1997; Lo et al. 1998). The (Xu et al. 2013). PRMT1 bound to the type II binding is stabilized by interactions between receptor methylates Smad6, which is bound to the phosphorylated GS domain of TbRI and the type I receptor, only after ligand-induced Smads; however, in view of the high conserva- heteromeric receptor complex formation. This tion of the GS domain between the seven type modification of Smad6 releases the BMP type I I receptors, this interaction is likely to be less receptor from the negative control of Smad6 selective. and allows type I receptors to phosphorylate After phosphorylation by TbRI, Smad2 and BMP-specific R-Smads (Xu et al. 2013). Thus, 3 dissociate from the receptor and form trimeric the feedback induction of Smad6 (or Smad7) complexes with Smad4. Such complexes can levels by BMP (or TGF-b) signaling may indi- consist of one molecule of Smad4 together cate the necessity to reestablish steady-state re- with two Smad2, two Smad3, or one each of ceptor pools of low or no activity at all. Smad2 and Smad3. The same scenario applies TGF-b stimulation also induces the expres- to the BMP-specific Smads. Smad complexes sion of the serine/threonine kinase salt-induc- are translocated to the nucleus by specific ible kinase (SIK) of the AMP-activated protein mechanisms, where they regulate the transcrip- kinase (AMPK) family, which promotes ubiqui- tion of target genes, in cooperation with other tylation and degradation of TbRI, in a Smad7- coactivators, corepressors, or transcription fac- dependent manner (Kowanetz et al. 2008; Lo¨nn tors (Massague´ et al. 2005). et al. 2012). Although SIK is also induced by Whereas the Smad pathways are of crucial BMP signaling (Kowanetz et al. 2004), the im- importance for TGF-b signaling, there are pact of this kinase in regulating BMP receptor also non-Smad signaling pathways initiated by activity or stability has not yet been analyzed. the activated TGF-b receptors, including the

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Erk1/2, JNK and p38 MAP kinase pathways, diator of TGF-b-induced apoptosis and EMT. PI3-kinase, and Src and Rho GTPases (Mousta- Another member of the TRAF family (i.e., kas and Heldin 2005). TRAF4), has also been implicated in the activa- One mechanism whereby TGF-b stimula- tion of TAK1 (Zhang et al. 2013a). As TAK1 tion can activate the Erk1/2 MAP kinase is via signaling is primed, TRAF4 ubiquitylates recruitment of the adaptor Shc to tyrosine phos- Smurf2 and promotes recruitment of the phorylated residues in TbRI, as described above. USP15 deubiquitylase, causing TbRI stabiliza- The adaptor Grb2 in complex with Sos1, a nu- tion and enhanced TGF-b signaling (Zhang cleotide exchange protein for Ras, can then bind et al. 2013a). An additional ubiquitin ligase, X- totyrosine-phosphorylated residuesonShc,and linked inhibitor of apoptosis (XIAP) associates the activated Ras mediates activation of the with the TbRI in breast cancer cells and pro- Erk1/2 MAP kinase pathway (Lee et al. 2007). motes ubiquitylation of TAK1, which then acti- Activation of Erk1/2 downstream of tyrosine vates nuclear factor kB (NF-kB) transcriptional kinase receptors have been shown to mediate a activity (Neil et al. 2009). XIAP enhances both growth stimulation, and may thus account for Smad2/3 and TAK1/NF-kB signaling and con- the mitogenic effect of TGF-b seen in certain cell tributes to prometastatic responses to TGF-b. types. A possible explanation for the different In addition, TRAF6 has been shown to be efficiency in TGF-b-induced Erk1/2 MAP ki- involved in TGF-b-induced intramembrane nase activation came from the study of TGF-b cleavage of TbRI, resulting in the release of its signaling in dermal versus epidermal cells. In intracellular domain, which then is translocated dermal cells, where TbRII levels are high, TGF- to the nucleus where it drives an invasiveness b efficiently activated Erk1/2, whereas in epi- program (Mu et al. 2011). First, TGF-b pro- dermal cells with low levels of TbRII, Erk1/2 motes the activation of the metalloproteinase activation was actually inhibited; artificial ex- ADAM17 (also called TACE), in a TRAF6- and pression of TbRII in epidermal cells switched C (PKC)–z-dependent manner, these cells to Erk1/2 activation in response which results in cleavage of TbRI just outside to TGF-b stimulation (Bandyopadhyay et al. the plasma membrane releasing the extracellu- 2011). In this study, activation of Erk1/2MAP lar domain (Liu et al. 2009a; Mu et al. 2011); the kinase was found to be TbRI-independent. remaining plasma membrane–attached part of For several non-Smad pathways, the ubiq- the receptor then becomes susceptible to an ad- uitin ligase tumor necrosis factor receptor-asso- ditional cleavage by g-secretase in the trans- ciated factor 6 (TRAF6) has a crucial role. There membrane segment, which releases the intracel- is a consensus-binding motif for TRAF6 in the lular domain (Gudey et al. 2014). juxtamembrane part of TbRI, as well as in ALK- TAK1 is not only activated by TGF-b, but 6 (Sorrentino et al. 2008). TGF-b stimulation BMP-2 and BMP-4 also induce receptor-medi- enhances the binding of TRAF6 to TbRI and ated activation of TAK1, followed by MKK3/6 promotes its activation, in a receptor kinase- activation and p38 MAP kinase signaling, a independent manner. The activated TRAF6 pathway that mediates critical events during then ubiquitylates the MAP-kinase kinase ki- early embryogenesis (Shibuya et al. 1998). The nase TGF-b activated kinase 1 (TAK1), leading in vivo role of TAK1 as a mediator of BMP sig- to its activation (Sorrentino et al. 2008; Yama- naling is also supported by silencing the expres- shita et al. 2008; Kim et al. 2009). TAK1 then sion of this kinase in chondrocytes, where dif- phosphorylates and activates the MAP kinase ferentiation is impaired (Shim et al. 2009), and kinase (MKK) 3 or 6, which activate the p38 in the germline causing vascular defects similar MAP kinase; all three kinases of this pathway to the knockout of Smad5 (Jadrich et al. 2006). bind to Smad7, which acts as a scaffolding pro- Interestingly, neural crest–specific inactivation tein bringing the kinases close to each other and of TAK1 expression caused overall craniofacial close to TbRI, thereby facilitating TGF-b-in- hypoplasia, including cleft palate, and in addi- duced p38 activation. p38 is an important me- tion to the defective p38 MAP kinase signaling

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TGF-b Family Receptors

downstream of TGF-b and BMP, these animals pressed by phosphorylation by TbRII, which also showed defective R-Smad phosphoryla- facilitates the endocytosis of PTH1R (Qiu tion, especially at their linker region, suggesting et al. 2010). a central role of TAK1 as a coordinator of both MAP kinase and Smad functions in vivo (Yu- TGF-b RECEPTOR REGULATION BY moto et al. 2013). ENDOCYTOSIS TGF-b stimulation has also been shown to activate PI3-kinase (Yi et al. 2005) and the ty- TGF-b stimulated receptor complexes are inter- rosine kinase Src (Galliher and Schiemann nalized via clathrin-coated pits into early endo- 2006), but the mechanisms involved remain to somes (Hayes et al. 2002; Di Guglielmo et al. be elucidated. The carboxy-terminal tail of 2003), which is necessary for Smad activation BMPRII also binds Src and BMP signaling neg- (Penheiter et al. 2002). The internalization is atively regulates Src activity; on the other hand, dependent on interaction with the b2-adaptin BMPRII mutations associated with PAH release subunit of the clathrin-associated adaptor com- the associated Src from the receptor and thus plex AP2 (Yao et al. 2002). In the endosomes, permit more active signaling by the Src kinase the receptors encounter Smad anchor for recep- that contributes to overproliferation associated tor activation (SARA), which facilitates the pre- with this disease (Wong et al. 2005). sentation of Smad2, and to some extent Smad3, In addition to phosphorylating TbRI, to TbRI and promotes their phosphorylation TbRII contributes to signaling by phosphory- (Fig. 3) (Tsukazaki et al. 1998). SARA cooper- lating other substrates. Thus, the polarity com- ates with the cytoplasmic promyelocytic leuke- plex protein Par6 interacts with TbRI, which mia (cPML) tumor suppressor protein (Lin presents it to TbRII, whereafter TbRII phos- et al. 2004) and with the adaptor protein dis- phorylates Par6 (Ozdamar et al. 2005). This abled-2 (DAB2) (Hocevar et al. 2001), which leads to the recruitment of the ubiquitin ligase stabilize the complex. In an analogous manner, Smurf1, which polyubiquitylates the small endofin acts as an anchor for Smad1 in signal- GTPase RhoA and thereby promotes its protea- ing via BMP receptors (Shi et al. 2007). In the somal degradation. Because RhoA regulates the rest of this section, we will focus on TGF-b re- dynamics of tight junctions and the actin fila- ceptor endocytosis, which is best understood. mentsthat support the assemblyand function of BMP receptor endocytosis follows relatively such junctions, its loss causes tight junction dis- similar mechanisms and has recently been re- solution. On the BMP side, the long carboxy- viewed (Ehrlich et al. 2012). terminal tail of BMPRII recruits LIM kinase 1 If clathrin-dependent trafficking of TGF-b (LIMK1), which remains inactive and thus is receptors is perturbed, TGF-b-induced R-Smad prohibited from phosphorylating cofilin, the phosphorylation and signaling is suppressed, inhibitor of actin polymerization (Foletta et al. showing the importance of internalization for 2003). Because LIMK1 inactivates cofilin, the TGF-b signaling via Smad molecules (Hayes action of BMPRII promotes cofilin activity and et al. 2002; Di Guglielmo et al. 2003). After limits actin polymerization. However, an alter- internalization, most of the TGF-b receptors native mechanism has also been observed dur- are recycled back to the cell surface and can ing neuronal differentiation, whereby binding of serve again (Di Guglielmo et al. 2003). Both LIMK1 to BMPRII activates the kinase together internalization and recycling of TGF-b recep- with the Cdc42 small GTPase, promoting actin tors occur in the absence and presence of ligand polymerization and dendrite formation (Lee- binding (Mitchell et al. 2004). Recycling of Hoeflich et al. 2004). TbRI is promoted by interaction with the adap- TbRII also phosphorylates the parathyroid tor CIN85 and is dependent on Rab11-contain- hormone (PTH) type 1 receptor (PTH1R). ing recycling vesicles (Yakymovych et al. 2015), PTH1R is a G protein–coupled receptor that and recycling of TbRII is promoted by the adap- promotes bone formation; its signaling is sup- tor protein DAB2 (Penheiter et al. 2010). More-

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HA Extracellular space CD 44 ADAM12 E2/E3: Clathrin-coated Ub Caveolin-positive Ub UbcH7 pit Smurf1/2 lipid raft Ub CIN85 AS160 Ub WWP1 SARA ARK Smad7 DAB2 Recycling endosome DUBs: UCH37 Caveolin-positive USP4 endosome USP11 USP15 AMSH Early endosome Retromer CYLD Vps26 Ub Ub Ub Ub E2/E3 Smad7

AM12

AD Late endosome DUB SARA Lysosome DAB2 cPML CIN85

Receptor degradation Cytoplasm

Nucleus Nuclear Smad– complexes Activated non-Smad mediators

Figure 3. Internalization and intracellular sorting of transforming growth factor b (TGF-b) receptors. Ligand- induced TGF-b receptorcomplexes in an active, signaling form are shown. Single receptor subunits oroligomeric receptor complexes without ligand are not shown for simplicity. Complex N-glycans attached to the extracellular domain are shown by red chains. TGF-b signaling via Smads or non-Smad mediators can be initiated at the cell surface in clathrin-coated pits or in earlyendosomes. The transmembrane metalloproteinase ADAM12 promotes TGF-b receptor endocytosis. The membrane-bound adaptor protein SARA, and the adaptors DAB2, cPML, AS160, and CIN85 participate in the early steps of endocytosis and recycling, positively regulate receptor signaling. Receptors can recycle via the recycling endosome back to the cell surface (possibly in the absence of ligand; not shown), a process that is promoted by CIN85. The retromer associates with TbRII via its subunit Vps26 and promotes recycling. Moreover, AS160 promotes translocation of intracellularly located receptors to the cell surface. Receptors can enter the late endosome and either recycle or continue to the lysosomes where final receptor degradation takes place. Receptors internalized by lipid rafts enter caveolin-positive vesicles and even- tually reach to lysosomes. TbRI binds Smad7, which carries several ubiquitin ligases (E2, E3) and deubiquitylases (DUBs) that regulate the rate and degree of ubiquitylation of the receptor (green molecules). Smad7 can also associate with ubiquitin ligases and DUBs that control its own ubiquitylation, and thus indirectly affect receptor internalization and degradation (red molecules). Proteasomal degradation of receptors and regulatory proteins occur during the internalization and sorting processes (not shown). Some of the molecules depicted in the figure have not been discussed in the text, such as UbcH7, WWP1, ARK, UCH37, AMSH, and CYLD. For authoritative discussion of the mechanisms of ubiquitylation and deubiquitylation during TGF-b family signaling, the reader is addressed to recent review articles (De Boeck and ten Dijke 2012; Herhaus and Sapkota 2014).

over, there appears to exist an intracellular pool GTPase AS160 (Budi et al. 2015). Akt is activat- of TGF-b receptors (Wu and Derynck 2009), ed by PI3-kinase (e.g., downstream of tyrosine which can be mobilized to presentation at the kinase receptors), such as the ; cell surface by Akt-induced phosphorylation thus, activation of such receptors makes cells of the endosomal membrane-associated Rab- more susceptible to TGF-b stimulation.

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TGF-b Family Receptors

TbRII phosphorylates the carboxyl tail of lateral side of TbRII is dependent on an betaglycan, which promotes clathrin-depen- LTAxxVAxxFmotif between amino acid residues dent endocytosis of the TGF-b receptor com- 529 and 538 in the receptor (Murphyet al. 2007). plex (Chen et al. 2003). TbRII also binds the Betaglycan also localizes to the basolateral part retromer vacuolar protein-sorting protein 26 of polarized mammary epithelial cells, and mu- (Vps26) in a TGF-b-independent manner; tation of Pro826 in the short cytoplasmic do- this interaction was found to be of crucial im- main of this receptor caused loss of cell polarity portance for proper receptor recycling and for and induction of EMT (Meyer et al. 2014). insertion of the receptor on the basolateral side of polarized MDCK epithelial cells (Yin et al. MUTATIONS OF SERINE/THREONINE 2013). KINASE RECEPTOR GENES IN DISEASES In addition to internalization via clathrin- coated pits, which promotes Smad signaling, Mutations in genes encoding members of the TGF-b receptors can be internalized via lipid serine/threonine kinase receptor family have rafts into caveolin-coated vesicles, which pro- been observed in a number of different diseases. motes receptor degradation (Fig. 3) (Razani et al. 2001). Through this pathway, TGF-b re- Malignancies ceptors interact with the Smad7/Smurf2 ubiq- uitylation complex and are degraded in pro- Inactivating mutations in the TGFBR2 gene are teasomes and lysosomes (Di Guglielmo et al. common in carcinomas of colon, rectum, blad- 2003). Not only TbRII and TbRI, but also be- der, head, and neck, implying that TGF-b sig- taglycan can be internalized by either clathrin- naling serves an important tumor-suppressive dependent or clathrin-independent mecha- role in these tissues (Kandoth et al. 2013). In- nisms (Finger et al. 2008). Clathrin-indepen- terestingly, mutations in TGF-b receptor genes dent internalization of betaglycan seems to be are much less common in, for example, breast required for efficient activation of both Smad2 cancer and leukemias. Cancer development in and p38 MAP kinase phosphorylation. Phos- the intestinal epithelium presents one of the phorylation of betaglycan on Thr841 by TbRII best-characterized examples of tumor suppres- promotes the association of the scaffolding pro- sor functions of TGF-b and BMP signaling. The tein b-arrestin, which mediates interaction with gene-encoding TbRII is frequently mutated flottilin of lipid rafts and promotes endocytosis (30% of all cases) in colorectal cancer patients of betaglycan (Chen et al. 2003). TbRII was (Biswas et al. 2008). A characteristic subclass of found to bind the transmembrane metallopro- colorectal malignancy is known as microsatellite teinase ADAM12, which, in a protease-inde- instable (MSI) tumors, and, in such cases, the pendent manner, promotes sorting of TbRII gene encoding TbRII is mutated with a frequen- to early endosomes, competes with its binding cy of higher than 90%. MSI tumors have defec- to Smad7, and thereby prevents its degradation tive mismatch repair machineries that frequent- (Atfi et al. 2007). Constitutive TGF-b receptor ly lead to replication errors, especially when the internalization can also be regulated by the de- DNA sequence contains long stretches of ade- gree of N-linked glycosylation of the receptors nine- or thymidine-based deoxynucleotides. (Partridge et al. 2004). The b1,6-N-acetyl-glu- Exon 3 of the TGFBR2 gene contains a polyade- cosaminyl- V (Mgat5) is transcrip- nine tract that is mutated and which has been tionally up-regulated in human cancers and gly- classified as the BAT-RII mutant receptor gene, cosylates the TGF-b receptors leading to resulting in frameshift mutations that encode prolonged residence of the receptors on the prematurely terminated, in other words, trun- cell surface. cated mutant receptors (Biswas et al. 2008). In- Both TbRI and TbRII are localized to the terestingly, the development of such mutant basolateral part of polarized epithelial cells TGF-b receptors has been proposed to result (Murphy et al. 2004). The delivery to the baso- from the combination of a hypermutable geno-

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mic location and a potent selection process that pends on the balanced activity of the PI3-ki- promotes the evolution of intestinal epithelial nase/Akt kinases, which is under the control cells that show resistance to the potent antipro- of the phosphatase PTEN. It is, therefore, in- liferative signals of TGF-b (Biswas et al. 2008). triguing that JPS patient intestinal epithelial Not only TbRII but also TbRI can suffer from a cells show mutations in the genes encoding similar hypermutable polyadenine tract caused BMPRIA/ALK-3, Smad4, and PTEN, develop- by mismatch repair defects, and the mutant al- ing defective BMP pathways and hyperactive lele known as TbRI6A has been proposed to Wnt-b-catenin signaling, thus promoting an predispose to colon cancer with a frequency of imbalanced stem-cell production that promotes 100%; however, careful examination of cohorts hyperplastic growth (He et al. 2004). From a of colon cancer patients carrying a mutation in structural point of view, it is very interesting this genetic has generated certain doubts that specific mutations that accumulate in the as to whether such mutations are causative BMPR1A/ALK 3 gene map in the region encod- elements in the development of intestinal tu- ing the extracellular domain but not the ligand- mors (Bian et al. 2005). Another type of intes- binding interface of the receptor (Kotzsch et al. tinal malignancy, the hereditary nonpolyposis 2008). Thus, structural modeling suggests that colorectal cancer that does not depend on mis- the ALK-3 gene mutations affect the global fold- match repair defects, shows mutations in the ing of the ectodomain of this receptor, thus BMPR1A/ALK3 gene; genetic screening for making the mutants resistant to the physiolog- this predisposing gene is warranted for signifi- ical action of BMPs in the intestinal microenvi- cant cohorts of families with genealogical his- ronment, causing JPS as explained above. tories on this type of cancer (Nieminen et al. 2011). Hereditary Hemorrhagic Telangiectasia Not only colorectal cancer depends on ge- netic predisposition that maps to the TGF-b Hereditary hemorrhagic telangiectasia (HHT) receptor genes. B lymphocyte malignancies, is an autosomal dominant vascular disorder, and especially chronic lymphocytic leukemias, which is characterized by mucocutanous telan- frequently develop resistance to the antiprolifer- giectases and arteriovenous malformations. It ative actions of TGF-b; this can be attributable has been shown that heterozygous mutations to mutations in the signal sequence of TbRI, in the genes for endoglin and ALK-1 cause causing a threshold effect as fewer receptors HHT1 and HHT2, respectively (McAllister reach the plasma membrane, rendering the sus- et al. 1994; Johnson et al. 1996; Abdalla et al. ceptible B cells prone to disobey physiological 2005). These observations suggest that endoglin TGF-b signaling (Schiemann et al. 2004). and ALK-1 operate in the same signaling path- way in endothelial cells, and that perturbation of either of them can cause HHT. Because ALK- Juvenile Polyposis Syndrome 1 signaling in endothelial cells was found to be Juvenile polyposis syndrome (JPS) patients de- independent of TbRII, the ligand involved is velop hamartomatous polyps in the intestine, unlikely to be a TGF-b isoform; possibly which is associated with an increased risk for BMP-9 or BMP-10 are the most important ac- adenocarcinoma. Germline loss-of-function tivators of ALK-1 in vivo (Park et al. 2008). mutations in the ALK3 gene has been observed in 20%–25% of JPS patients (Howe et al. 2001, 2004). BMP signaling is known to antagonize Loeys–Dietz Syndrome, Marfan Syndrome, and Familial Thoracic Aortic Aneurysms and Wnt pathway function in the intestinal stem-cell Dissections compartment, causing a balanced generation of intestinal stem cells during the life span of the Loeys–Dietz syndrome (LDS), Marfan syn- intestinal epithelium (He et al. 2004). In addi- drome (MFS), and familial thoracic aortic an- tion, physiological Wnt-b-catenin signaling de- eurysms and dissections (TAAD) are diseases

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that are characterized by skeletal abnormalities, GS domain of ActRI/ALK-2 (Shore et al. aortic dilations, aneurysms, and ectopia lentis; 2006; Kaplan et al. 2009). The mutated receptor these diseases involve alterations in TGF-b sig- requires the presence of a type II receptor, either naling (Neptune et al. 2003; Habashi et al. the BMP type II receptor or ActRII, for full 2006), including mutations in the genes encod- activity; the kinase activity of the type II recep- ing TbRI and TbRII (Mizuguchi et al. 2004; tor is not needed suggesting that it acts as a Loeys et al. 2005, 2006; Pannu et al. 2005; Singh scaffolding molecule (Bagarova et al. 2013). In- et al. 2006; LeMaire et al. 2007). A quantitative terestingly, the most common ACVR1 muta- analysis of different TbRII mutants revealed a tion, resulting in an R206H substitution, was correlation between phenotypic severity and shown to induce FOP by gaining responsiveness loss of Smad signaling activity (Horbelt et al. to activin stimulation, which normally antago- 2010). nizes BMP signaling and prevents bone forma- tion (Hatsell et al. 2015). Thus, treatment with activin antibodies offers a possible therapy for Idiopathic Pulmonary Arterial Hypertension patients with FOP. Idiopathic pulmonary arterial hypertension (IPAH) is characterized by an increased pulmo- nary artery pressure leading to failure of the Diffuse Intrinsic Pontine Glioma right ventricle of the heart (Eddahibi et al. Activating mutations of ACVR1/ALK2 have 2002), and involves loss-of-function mutations also been found in about 20% of diffuse intrin- in the gene encoding the BMPRII (Machado sic pontine gliomas (DIPGs) (Buczkowicz et al. et al. 2001; Thomson et al. 2001). Mutations 2014; Taylor et al. 2014). Such mutations were have been observed in the part of the gene en- linked to increased phosphorylation of Smad1, coding the extracellular domain, the kinase do- 5, and 8, suggesting that, in this type of tumor, main, as well as the carboxy-terminal extension activation of BMP Smads has a protumorigenic that is characteristic for this receptor. The mu- effect. tations in the carboxy-terminal tail may perturb interaction with Trb3; because Trb3 promotes proteasomal degradation of the ubiquitin ligase Smurf1 and thus stabilizes the receptor and pro- INHIBITION OF SIGNALING VIA PHARMACOLOGICAL TARGETING motes signaling, loss of this interaction sup- OF TGF-b RECEPTORS presses signaling via this receptor (Chan et al. 2007). Trb3 can be down-regulated by the ac- The fact that increased activity of TGF-b signal- tion of miR-24, whose expression is induced by ing is associated with tumor progression, fibro- PDGF signaling in vascular smooth muscle cells sis, immunosuppression, and other diseases, (Chan et al. 2010). This mechanism explains has prompted the development of TGF-b sig- how PDGF can antagonize BMP signaling and naling inhibitors (Akhurst and Hata 2012). thus promote smooth muscle–cell proliferation Such inhibitors include inhibitory antibodies bypassing the quiescence induced by BMPs. against TGF-b or TGF-b receptors (Zhong et al. 2010) or ligand traps consisting of soluble extracellular domains of TGF-b receptors. A Fibrodysplasia Ossificans Progressiva soluble TbRII extracellular domain has been Fibrodysplasia ossificans progressive (FOP) is a shown to inhibit tumor progression in animal congenital heterotopic ossification disorder, tumor models (Saunier and Akhurst 2006), and which is characterized by endochondral bone a soluble ALK-1 extracellular domain has been lesions in soft tissues, specifically following in- shown to have antiangiogenic properties and to jury or inflammation (Kaplan et al. 2008). FOP inhibit tumor growth in mouse models (Cunha is caused by activating mutation in the sequence et al. 2010). Moreover, an antibody against of the ACVR1/ALK2 gene that encodes the ALK-1 was found to inhibit endothelial cell

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sprouting and angiogenesis (van Meeteren et al. TbRII functions via a constitutively active ki- 2012). nase mode instead of activating its kinase activ- Low molecular weight inhibitors of the ity after ligand binding may provide deeper TGF-b receptor kinases represent another type understanding of the early signaling events by of TGF-b inhibitor. These compounds often TGF-b family receptors. Signaling via Smad compete with binding of ATP to the ATP-bind- molecules has been explored in some detail, ing site of the kinase, and several of them inhibit but we still do not understand the full repertoire the TbRI kinase selectively, but often also inhib- of non-Smad signaling pathways, or their it the activin type I receptor ALK-4 and the no- mechanisms of activation or function. dal type I receptor ALK-7 (Yingling et al. 2004). With the aim of treating diseases in which TbRI kinase inhibitors have been shown, in an- TGF-b signaling is overactive, including ad- imal models, to inhibit invasion and metastasis vanced cancers, TGF-b signaling receptors of, for example, breast cancer cells (Bandyopad- have been targeted with some encouraging re- hyay et al. 2006; Ge et al. 2006; Ehata et al. 2007; sults. Future studies will be aimed at exploring Liu et al. 2012), melanoma cells (Mohammad the efficacy of such inhibitors for treatment of et al. 2011), glioma cells (Uhl et al. 2004; Zhang various tumors and tumor subtypes. et al. 2011), and mesothelioma cells (Suzuki et al. 2007). The effect of the inhibitors include inhibition of mesenchymal transition of the tu- ACKNOWLEDGMENTS mor cells, activation of the immune system, in- ¨ hibition of angiogenesis, inhibition of osteolysis We thank Ingegard Schiller for secretarial assis- preventing bone metastasis, and normalization tance, and all past and present members of the TGF-b signaling group for their contributions of tumor stroma. In a recent clinical dose- escalation analysis, the TbRI kinase inhibitor to the scientific work emanating from our lab- LY2157299 monohydrate (also named galuni- oratory. This article summarizes work from a large number of published papers; however, be- sertib) proved to be efficacious against malig- nant glioma (Rodon et al. 2015a,b). Previous cause of space limitations we have been unable animal experiments reported severe cardiac to include all relevant publications in our dis- cussion. We apologize to those authors whose side effects of TbRI kinase inhibitors; however, no cardiotoxicity was recorded in patients treat- relevant work has not been included in this re- ed with galunisertib, providing support for the view article. We acknowledge funding by the Ludwig Institute for Cancer Research, the Swed- possibility that anti-TGF-b drugs can be clini- cally useful (Kovacs et al. 2015). ish Cancer Society, the Swedish Research Coun- cil, the Network of Excellence “ENFIN” under the European Union FP6 program, and the Ini- CONCLUDING REMARKS tial Training Network “IT-Liver” under the Eu- The structural and functional properties of the ropean Union FP7 program. receptors for TGF-b family members have been characterized during the last 20 years. We now have insight into the three-dimensional struc- REFERENCES tures of certain of these receptors, with or with- Abdalla SA, Cymerman U, Rushlow D, Chen N, Stoeber GP, out ligand bound, as well as their specificities Lemire EG, Letarte M. 2005. Novel mutations and poly- for ligand binding and functions during embry- morphisms in genes causing hereditary hemorrhagic tel- angiectasia. Hum Mutat 25: 320–321. onic development and in the adult. Abdollah S, Macı´as-Silva M, Tsukazaki T, Hayashi H, Atti- With regard to TbRI and TbRII, we know sano L, Wrana JL. 1997. TbRI phosphorylation of Smad2 that these receptors are carefully controlled by on Ser465 and Ser467 is required for Smad2–Smad4 com- plex formation and signaling. J Biol Chem 272: 27678– posttranslational modifications, and that their 27685. endocytosis and intracellular sorting are crucial Akhurst RJ, Hata A. 2012. Targeting the TGFb signalling for their signaling. Explaining further why pathway in disease. Nat Rev Drug Discov 11: 790–811.

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Al-Salihi MA, Herhaus L, Macartney T, Sapkota GP. 2012. b co-receptor, CD109, promotes internalization and deg- USP11 augments TGF b signalling by deubiquitylating radation of TGF-b receptors. Biochem Biophys Acta 1813: ALK5. Open Biol 2: 120063. 742–753. Arthur HM, Ure J, Smith AJ, Renforth G, Wilson DI, Tors- Bizet AA, Tran-Khanh N, Saksena A, Liu K, Buschmann ney E, Charlton R, Parums DV, Jowett T, Marchuk DA, MD, Philip A. 2012. CD109-mediated degradation of et al. 2000. Endoglin, an ancillary TGFb receptor, is re- TGF-b receptors and inhibition of TGF-b responses in- quired for extraembryonic angiogenesis and plays a key volve regulation of SMAD7 and Smurf2 localization and role in heart development. Dev Biol 217: 42–53. function. J Cell Biochem 113: 238–246. Aspalter IM, Gordon E, Dubrac A, Ragab A, Narloch J, Bourguignon LY, Singleton PA, Zhu H, Zhou B. 2002. Hya- Vizan P, Geudens I, Collins RT, Franco CA, Abrahams luronan promotes signaling interaction between CD44 CL, et al. 2015. Alk1 and Alk5 inhibition by Nrp1 controls and the transforming growth factor b receptor I in met- vascular sprouting downstream of Notch. Nat Commun astatic breast tumor cells. J Biol Chem 277: 39703–39712. 6: 7264. Brock M, Trenkmann M, Gay RE, Michel BA, Gay S, Fischler Atfi A, Dumont E, Colland F, Bonnier D, L’Helgoualc’h A, M, Ulrich S, Speich R, Huber LC. 2009. Interleukin-6 Prunier C, Ferrand N, Clement B, Wewer UM, Theret N. modulates the expression of the bone morphogenic pro- 2007. The disintegrin and metalloproteinase ADAM12 tein receptor type II through a novel STAT3-microRNA contributes to TGF-b signaling through interaction cluster 17/92 pathway. Circ Res 104: 1184–1191. with the type II receptor. J Cell Biol 178: 201–208. Buczkowicz P,Hoeman C, Rakopoulos P,Pajovic S, Letour- Babitt JL, Huang FW, Wrighting DM, Xia Y, Sidis Y, Samad neau L, Dzamba M, Morrison A, Lewis P, Bouffet E, TA, Campagna JA, Chung RT, Schneyer AL, Woolf CJ, Bartels U, et al. 2014. Genomic analysis of diffuse intrin- et al. 2006. Bone morphogenetic protein signaling by sic pontine gliomas identifies three molecular subgroups hemojuvelin regulates hepcidin expression. Nat Genet and recurrent activating ACVR1 mutations. Nat Genet 38: 531–539. 46: 451–456. Bagarova J, Vonner AJ, Armstrong KA, Borgermann J, Lai Budi EH, Muthusamy BP, Derynck R. 2015. The insulin CSC, Deng DY, Beppu H, Alfano I, Filippakopoulos P, response integrates increased TGF-b signaling through Morrell NW, et al. 2013. Constitutively active ALK2 re- Akt-induced enhancement of cell surface delivery of ceptor mutants require type II receptor cooperation. Mol TGF-b receptors. Sci Signal 8: e80630. Cell Biol 33: 2413–2424. Cao Y,Szabolcs A, Dutta SK, YaqoobU, Jagavelu K, Wang L, Bandyopadhyay A, Agyin JK, Wang L, Tang Y, Lei X, Story Leof EB, Urrutia RA, Shah VH, Mukhopadhyay D. 2010. BM, Cornell JE, Pollock BH, Mundy GR, Sun LZ. 2006. Neuropilin-1 mediates divergent R-Smad signaling and Inhibition of pulmonary and skeletal metastasis by a the myofibroblast phenotype. J Biol Chem 285: 31840– transforming growth factor-b type I receptor kinase in- 31848. hibitor. Cancer Res 66: 6714–6721. Chaikuad A, Alfano I, Kerr G, Sanvitale CE, Boergermann Bandyopadhyay B, Han A, Dai J, Fan J, Li Y,Chen M, Wood- JH, Triffitt JT,von Delft F,Knapp S, Knaus P,Bullock AN. ley DT, Li W. 2011. TbRI/Alk5-independent TbRII sig- 2012. Structure of the bone morphogenetic protein re- naling to ERK1/2 in human skin cells according to dis- ceptor ALK2 and implications for fibrodysplasia ossifi- tinct levels of TbRII expression. J Cell Sci 124: 19–24. cans progressiva. J Biol Chem 287: 36990–36998. Barbara NP, Wrana JL, Letarte M. 1999. Endoglin is an ac- Champion A, Kreis M, Mockaitis K, Picaud A, Henry Y. cessory protein that interacts with the signaling receptor 2004. Arabidopsis kinome: After the casting. Funct Integr complex of multiple members of the transforming Genomics 4: 163–187. growth factor-b superfamily. J Biol Chem 274: 584–594. Chan MC, Nguyen PH, Davis BN, Ohoka N, Hayashi H, Du Barrios-Rodiles M, Brown KR, Ozdamar B, Bose R, Liu Z, K, Lagna G, Hata A. 2007. A novel regulatory mechanism Donovan RS, Shinjo F,Liu Y,Dembowy J, Taylor IW,et al. of the bone morphogenetic protein (BMP) signaling 2005. High-throughput mapping of a dynamic signaling pathway involving the carboxyl-terminal tail domain of network in mammalian cells. Science 307: 1621–1625. BMP type II receptor. Mol Cell Biol 27: 5776–5789. Batut J, Schmierer B, Cao J, Raftery LA, Hill CS, Howell M. Chan MC, Hilyard AC, Wu C, Davis BN, Hill NS, Lal A, 2008. Two highly related regulatory subunits of PP2A Lieberman J, Lagna G, Hata A. 2010. Molecular basis for exert opposite effects on TGF-b/activin/nodal signal- antagonism between PDGF and the TGFb family of sig- ling. Development 135: 2927–2937. nalling pathways by control of miR-24 expression. EMBO Bian Y,Caldes T,Wijnen J, Franken P,VasenH, Kaklamani V, J 29: 559–573. Nafa K, Peterlongo P, Ellis N, Baron JA, et al. 2005. Chang CYY, Chen Y, Lai MT, Chang HW, Cheng J, Chan C, TGFBR16A may contribute to hereditary colorectal can- Chen CM, Lee SC, Lin YJ, Wan L, et al. 2013. BMPR1B cer. J Clin Oncol 23: 3074–3078. up-regulation via a miRNA variation defines Biswas S, Trobridge P,Romero-Gallo J, Billheimer D, Myer- endometriosis susceptibility and CA125 levels. PLoS offs LL, Willson JKV, Markowitz SD, Grady WM. 2008. ONE 8: e80630. Mutational inactivation of TGFBR2 in microsatellite un- Chen RH, Derynck R. 1994. Homomeric interactions be- stable colon cancer arises from the cooperation of geno- tween type II transforming growth factor-b receptors. J mic instability and the clonal outgrowth of transforming Biol Chem 269: 22868–22874. growth factor b resistant cells. Genes Chromos Cancer 47: Chen YG, Liu F, Massague´ J. 1997. Mechanism of TGFb 95–106. receptor inhibition by FKBP12. EMBO J 16: 3866–3876. Bizet AA, Liu K, Tran-Khanh N, Saksena A, Vorstenbosch J, Chen TP,Carter D, Garrigue-Antar L, Reiss M. 1998. Trans- Finnson KW,Buschmann MD, Philip A. 2011. The TGF- forming growth factor-b type I receptor kinase mutant

Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a022053 23 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press

C.-H. Heldin and A. Moustakas

associated with metastatic breast cancer. Cancer Res 58: Eddahibi S, Morrell N, d’Ortho MP,Naeije R, Adnot S. 2002. 4805–4810. Pathobiology of pulmonary arterial hypertension. Eur Chen T, Yan W, Wells RG, Rimm DL, McNiff J, Leffell D, Respir J 20: 1559–1572. Reiss M. 2001. Novel inactivating mutations of trans- Ehata S, Hanyu A, Fujime M, Katsuno Y, Fukunaga E, Goto forming growth factor-b type I receptor gene in head- K, Ishikawa Y,Nomura K, Yokoo H, Shimizu T,et al. 2007. and-neck cancer metastases. Int J Cancer 93: 653–661. Ki26894, a novel transforming growth factor-b type I Chen W, Kirkbride KC, How T, Nelson CD, Mo J, Frederick receptor kinase inhibitor, inhibits in vitro invasion and JP, Wang XF, Lefkowitz RJ, Blobe GC. 2003. b-arrestin 2 in vivo bone metastasis of a human breast cancer cell line. mediates endocytosis of type III TGF-b receptor and Cancer Sci 98: 127–133. down-regulation of its signaling. Science 301: 1394– Ehrlich M, Gutman O, Knaus P,Henis YI. 2012. Oligomeric 1397. interactions of TGF-b and BMP receptors. FEBS Lett 586: Chen XW,Wang HT,Liao HJ, Hu W,Gewin L, Mernaugh G, 1885–1896. Zhang S, Zhang ZY,Vega-Montoto L, Vanacore RM, et al. Eichhorn PJ, Rodon L, Gonzalez-Junca A, Dirac A, Gili M, 2014. Integrin-mediated type II TGF-b receptor tyrosine Martinez-Saez E, Aura C, Barba I, Peg V, Prat A, et al. dephosphorylation controls SWIAD-dependent profi- 2012. USP15 stabilizes TGF-b receptor I and promotes brotic signaling. J Clin Invest 124: 3295–3310. oncogenesis through the activation of TGF-b signaling in Cunha SI, Pardali E, Thorikay M, Anderberg C, Hawinkles glioblastoma. Nat Med 18: 429–435. L, Goumans MJ, Seehra J, Heldin CH, ten Dijke P,Pietras Eickelberg O, Centrella M, Reiss M, Kashgarian M, Wells K. 2010. Genetic and pharmacological targeting of acti- RG. 2002. Betaglycan inhibits TGF-b signaling by pre- vin receptor-like kinase 1 impairs tumor growth and an- venting type I-type II receptor complex formation. Gly- giogenesis. J Exp Med 207: 85–100. cosaminoglycan modifications alter betaglycan function. J Biol Chem 277: 823–829. Daly AC, Randall RA, Hill CS. 2008. Transforming growth factor b-induced Smad1/5 phosphorylation in epithelial Elderbroom JL, Huang JJ, Gatza CE, Chen J, How T,Starr M, cells is mediated by novel receptor complexes and is es- Nixon AB, Blobe GC. 2014. Ectodomain shedding of sential for anchorage-independent growth. Mol Cell Biol TbRIII is required for TbRIII-mediated suppression of 28: 6889–6902. TGF-b signaling and breast cancer migration and inva- sion. Mol Biol Cell 25: 2320–2332. Datta PK, Moses HL. 2000. STRAP and Smad7 synergize in the inhibition of transforming growth factor b signaling. Faherty N, Curran SP, O’Donovan H, Martin F, Godson C, Mol Cell Biol 20: 3157–3167. Brazil DP,Crean JK. 2012. CCN2/CTGF increases expres- sion of miR-302 microRNAs, which target the TGFb type Datta PK, Chytil A, Gorska AE, Moses HL. 1998. Identifi- II receptor with implications for nephropathic cell phe- cation of STRAP, a novel WD domain protein in trans- notypes. J Cell Sci 125: 5621–5629. forming growth factor-b signaling. J Biol Chem 273: 34671–34674. Felici A, Wurthner JU, Parks WT, Giam LR, Reiss M, Kar- pova TS, McNally JG, Roberts AB. 2003. TLP, a novel David L, Mallet C, Mazerbourg S, Feige JJ, Bailly S. 2007. modulator of TGF-b signaling, has opposite effects on Identification of BMP9 and BMP10 as functional activa- Smad2- and Smad3-dependent signaling. EMBO J 22: tors of the orphan activin receptor-like kinase 1 (ALK1) 4465–4477. in endothelial cells. Blood 109: 1953–1961. Feng XH, Derynck R. 1997. A kinase subdomain of trans- De Boeck M, ten Dijke P.2012. Key role for ubiquitin protein forming growth factor-b (TGF-b) type I receptor deter- modification in TGFb signal transduction. Ups J Med Sci mines the TGF-b intracellular signaling specificity. 117: 153–165. EMBO J 16: 3912–3923. Derynck R, Miyazono K, ed. 2008. The TGF-b family. Feng XH, Derynck R. 2005. Specificity and versatility in Cold Spring Harbor Laboratory Press, Cold Spring TGF-b signaling through Smads. Annu Rev Cell Dev Harbor, NY. Biol 21: 659–693. Di Guglielmo GM, Le Roy C, Goodfellow AF, Wrana JL. Feng NH, Xu B, TaoJ, Li PC, Cheng G, Min ZC, Mi YY,Wang 2003. Distinct endocytic pathways regulate TGF-b recep- ML, TongN, TangJL, et al. 2012. A miR-125b binding site tor signalling and turnover. Nat Cell Biol 5: 410–421. polymorphism in bone morphogenetic protein mem- Dong M, How T,Kirkbride KC, Gordon KJ, Lee JD, Hempel brane receptor type IB gene and prostate cancer risk in N, Kelly P, Moeller BJ, Marks JR, Blobe GC. 2007. The China. Mol Biol Rep 39: 369–373. type III TGF-b receptor suppresses breast cancer progres- Ferrand N, Atfi A, Prunier C. 2010. The oncoprotein c-ski sion. J Clin Invest 117: 206–217. functions as a direct antagonist of the transforming Durrington HJ, Upton PD, Hoer S, Boname J, Dunmore BJ, growth factor-b type I receptor. Cancer Res 70: 8457– Yang J, Crilley TK, Butler LM, Blackbourn DJ, Nash GB, 8466. et al. 2010. Identification of a lysosomal pathway regulat- Ferrigno O, Lallemand F,Verrecchia F,L’Hoste S, Camonis J, ing degradation of the bone morphogenetic protein re- Atfi A, Mauviel A. 2002. Yes-associated protein (YAP65) ceptor type II. J Biol Chem 285: 37641–37649. interacts with Smad7 and potentiates its inhibitory activ- Ebisawa T, Fukuchi M, Murakami G, Chiba T, Tanaka K, ity against TGF-b/Smad signaling. 21: 4879– Imamura T, Miyazono K. 2001. Smurf1 interacts with 4884. transforming growth factor-b type I receptor through Finger EC, Lee NY, You HJ, Blobe GC. 2008. Endocytosis of Smad7 and induces receptor degradation. J Biol Chem the type III transforming growth factor-b (TGF-b)re- 276: 12477–12480. ceptor through the clathrin-independent/lipid raft path-

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TGF-b Family Receptors

way regulates TGF-b signaling and receptor down-regu- Grotewold L, Plum M, Dildrop R, Peters T, Ruther U. 2001. lation. J Biol Chem 283: 34808–34818. Bambi is coexpressed with BMP-4 during mouse em- Finnson KW, Tam BY, Liu K, Marcoux A, Lepage P, Roy S, bryogenesis. Mech Dev 100: 327–330. Bizet AA, Philip A. 2006. Identification of CD109 as part Gudey SK, Sundar R, Mu Y, Wallenius A, Zang G, Bergh A, of the TGF-b receptor system in human keratinocytes. Heldin CH, Landstro¨m M. 2014. TRAF6 stimulates the FASEB J 20: 1525–1527. tumor-promoting effects of TGFb type I receptor Foletta VC, Lim MA, Soosairajah J, Kelly AP, Stanley EG, through polyubiquitination and activation of presenilin Shannon M, He W, Das S, Massague´ J, Bernard O. 2003. 1. Sci Signal 7: ra2. Direct signaling by the BMP type II receptor via the cy- Guerrero-Esteo M, Sanchez-Elsner T, Letamendia A, Berna- toskeletal regulator LIMK1. J Cell Biol 162: 1089–1098. beu C. 2002. Extracellular and cytoplasmic domains of Galliher AJ, Schiemann WP.2006. b3 integrin and Src facil- endoglin interact with the transforming growth factor-b itate transforming growth factor-b mediated induction receptors I and II. J Biol Chem 277: 29197–29209. of epithelial–mesenchymal transition in mammary epi- Guo M, Jiang ZF, Zhang XM, Lu DY, Ha AD, Sun JH, Du thelial cells. Breast Cancer Res 8: R42. WZ, Wu ZC, Hu L, Khadarian K, et al. 2014. miR-656 Galliher AJ, Schiemann WP. 2007. Src phosphorylates inhibits glioma tumorigenesis through repression of Tyr284 in TGF-b type II receptor and regulates TGF-b BMPR1A. Carcinogenesis 35: 1698–1706. stimulation of p38 MAPK during breast cancer cell pro- Habashi JP,Judge DP,Holm TM, Cohn RD, Loeys BL, Coo- liferation and invasion. Cancer Res 67: 3752–3758. per TK, Myers L, Klein EC, Liu G, Calvi C, et al. 2006. Galliher-Beckley AJ, Schiemann WP.2008. Grb2 binding to Losartan, an AT1antagonist, prevents aortic aneurysm in Tyr284 in TbR-II is essential for mammary tumor growth a mouse model of Marfan syndrome. Science 312: 117– and metastasis stimulated by TGF-b. Carcinogenesis 29: 121. 244–251. Hart PJ, Deep S, Taylor AB, Shu Z, Hinck CS, Hinck AP. Ge R, Rajeev V, Ray P, Lattime E, Rittling S, Medicherla S, 2002. Crystal structure of the human TbR2 ectodomain– Protter A, Murphy A, Chakravarty J, Dugar S, et al. 2006. TGF-b3 complex. Nat Struct Biol 9: 203–208. Inhibition of growth and metastasis of mouse mammary Hatsell SJ, Idone V, Wolken DMA, Huang L, Kim HJ, Wang carcinoma by selective inhibitor of transforming growth LL, Wen XL, Nannuru KC, Jimenez J, Xie LQ, et al. 2015. factor-b type I receptor kinase in vivo. Clin Cancer Res 12: ACVR1R206H receptor mutation causes fibrodysplasia os- 4315–4330. sificans progressiva by imparting responsiveness to acti- Gilboa L, Wells RG, Lodish HF, Henis YI. 1998. Oligomeric vin A. Sci Transl Med 7: 303ra137. structure of type I and type II transforming growth factor Hayashi H, Abdollah S, Qiu Y, Cai J, Xu YY, Grinnell BW, b receptors: Homodimers form in the ER and persist at Richardson MA, Topper JN, Gimbrone MAJ, Wrana JL, the plasma membrane. J Cell Biol 140: 767–777. et al. 1997. The MAD-related protein Smad7 associates Glinka Y, Prud’homme GJ. 2008. Neuropilin-1 is a receptor with the TGFb receptor and functions as an antagonist of for latent and active TGFb-1and is involved in suppres- TGFb signaling. Cell 89: 1165–1173. sion by regulatory T cells. FASEB J 22: 664.4. Hayes S, Chawla A, Corvera S. 2002. TGF b receptor inter- Glinka Y,Stoilova S, Mohammed N, Prud’homme GJ. 2011. nalization into EEA1-enriched early endosomes: Role in Neuropilin-1 exerts co-receptor function for TGF-b-1 on signaling to Smad2. J Cell Biol 158: 1239–1249. the membrane of cancer cells and enhances responses to He XC, Zhang JW, Tong WG, Tawfik O, Ross J, Scoville DH, both latent and active TGF-b. Carcinogenesis 32: 613– Tian Q, Zeng X, He X, Wiedemann LM, et al. 2004. BMP 621. signaling inhibits intestinal stem cell self-renewal Goto K, Kamiya Y, Imamura T, Miyazono K, Miyazawa K. through suppression of Wnt-b-catenin signaling. Nat 2007. Selective inhibitory effects of Smad6 on bone mor- Genet 36: 1117–1121. phogenetic protein type I receptors. J Biol Chem 282: Heldin CH, Lu B, Evans R, Gutkind S. 2014. Signals and 20603–20611. receptors. In Signal transduction principles, pathways and Goumans MJ, Valdimarsdottir G, Itoh S, Lebrin F,Larsson J, processes (ed. Cantley LC, Hunter T, Sever R, Thorner J), Mummery C, Karlsson S, ten Dijke P. 2003. Activin re- pp. 3–29. Cold Spring Harbor Laboratory, Cold Spring ceptor-like kinase (ALK)1 is an antagonistic mediator of Harbor, NY. lateral TGFb/ALK5 signaling. Mol Cell 12: 817–828. Henis YI, Moustakas A, Lin HY,Lodish HF. 1994. The types Gray PC, Shani G, Aung K, Kelber J, Vale W. 2006. Cripto II and III transforming growth factor-b receptors form binds transforming growth factor b (TGF-b) and inhibits homo-oligomers. J Cell Biol 126: 139–154. TGF-b signaling. Mol Cell Biol 26: 9268–9278. Herhaus L, Sapkota GP. 2014. The emerging roles of de- Griswold-Prenner I, Kamibayashi C, Maruoka EM, Mumby ubiquitylating enzymes (DUBs) in the TGFb and BMP MC, Derynck R. 1998. Physical and functional interac- pathways. Cell Signal 26: 2186–2192. tions between type I transforming growth factor b recep- Herhaus L, Al-Salihi MA, Dingwell KS, Cummins TD, Was- tors and Ba, a WD-40 repeat subunit of phosphatase 2A. mus L, VogtJ, Ewan R, Bruce D, Macartney T,WeidlichS, Mol Cell Biol 18: 6595–6604. et al. 2014. USP15 targets ALK3/BMPR1A for deubiqui- Groppe J, Hinck CS, Samavarchi-Tehrani P, Zubieta C, tylation to enhance bone morphogenetic protein signal- Schuermann JP,Taylor AB, Schwarz PM, Wrana JL, Hinck ling. Open Biol 4: 140065. AP. 2008. Cooperative assembly of TGF-b superfamily Hocevar BA, Smine A, Xu XX, Howe PH. 2001. The adaptor signaling complexes is mediated by two disparate mech- molecule disabled-2 links the transforming growth factor anisms and distinct modes of receptor binding. Mol Cell b receptors to the Smad pathway. EMBO J 20: 2789– 29: 157–168. 2801.

Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a022053 25 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press

C.-H. Heldin and A. Moustakas

Horbelt D, Guo G, Robinson PN, Knaus P.2010. Quantita- Jin W,Yun C, Kwak MK, Kim TA,Kim SJ. 2007c. TrkC binds tive analysis of TGFBR2 mutations in Marfan-syndrome- to the type II TGF-b receptor to suppress TGF-b signal- related disorders suggests a correlation between pheno- ing. Oncogene 26: 7684–7691. typic severity and Smad signaling activity. J Cell Sci 123: Jin QY, Ding W, Mulder KM. 2012. The TGFb receptor- 4340–4350. interacting protein km23-1/DYNLRB1 plays an adaptor Howe JR, Bair JL, Sayed MG, Anderson ME, Mitros FA, role in TGFb1 autoinduction via its association with Ras. Petersen GM, Velculescu VE, Traverso G, Vogelstein B. J Biol Chem 287: 26453–26463. 2001. Germline mutations of the gene encoding bone Johnson DW, Berg JN, Baldwin MA, Gallione CJ, Marondel morphogenetic protein receptor 1A in juvenile polyposis. I, Yoon SJ, Stenzel TT, Speer M, Pericak-Vance MA, Di- Nat Genet 28: 184–187. amond A, et al. 1996. Mutations in the activin receptor- Howe JR, Sayed MG, Ahmed AF,Ringold J, Larsen-Haidle J, like kinase 1 gene in hereditary haemorrhagic telangiec- Merg A, Mitros FA, Vaccaro CA, Petersen GM, Giardiello tasia type 2. Nat Genet 13: 189–195. FM, et al. 2004. The prevalence of MADH4 and BMPR1A Kamiya Y, Miyazono K, Miyazawa K. 2010. Smad7 inhibits mutations in juvenile polyposis and absence of BMPR2, transforming growth factor-b family type I receptors BMPR1B, and ACVR1 mutations. J Med Genet 41: 484– through two distinct modes of interaction. J Biol Chem 491. 285: 30804–30813. Huang T, David L, Mendoza V, Yang Y, Villarreal M, De K, Kandoth C, McLellan MD, Vandin F,YeK, Niu BF,Lu C, Xie Sun L, Fang X, Lopez-Casillas F, Wrana JL, et al. 2011. MC, Zhang QY, McMichael JF, Wyczalkowski MA, et al. TGF-b signalling is mediated by two autonomously 2013. Mutational landscape and significance across 12 functioning TbRI:TbRII pairs. EMBO J 30: 1263–1276. major cancer types. Nature 502: 333–339. Huang SD, Holzel M, Knijnenburg T,Schlicker A, Roepman Kang JS, Saunier EF,Akhurst RJ, Derynck R. 2008. The type I P, McDermott U, Garnett M, Grernrum W, Sun C, Pra- TGF-b receptor is covalently modified and regulated by hallad A, et al. 2012. MED12 controls the response to sumoylation. Nat Cell Biol 10: 654–664. b multiple cancer drugs through regulation of TGF- re- Kang H, Louie J, Weisman A, Sheu-Gruttadauria J, Davis- ceptor signaling. Cell 151: 937–950. Dusenbery BN, Lagna G, Hata A. 2012. Inhibition of Huminiecki L, Goldovsky L, Freilich S, Moustakas A, Ou- MicroRNA-302 (miR-302) by bone morphogenetic pro- zounis CA, Heldin CH. 2009. Emergence, development tein 4 (BMP4) facilitates the BMP signaling pathway. J and diversification of the TGF-b signalling pathway with- Biol Chem 287: 38656–38664. in the animal kingdom. BMC Evol Biol 9: 28. Kaplan FS, Le Merrer M, Glaser DL, Pignolo RJ, Goldsby RE, Huse M, Chen YG, Massague´ J, Kuriyan J. 1999. Crystal Kitterman JA, Groppe J, Shore EM. 2008. Fibrodysplasia structure of the cytoplasmic domain of the type I TGF ossificans progressiva. Best Pract Res Clin Rheumatol 22: b receptor in complex with FKBP12. Cell 96: 425–436. 191–205. Huse M, Muir TW, Xu L, Chen YG, Kuriyan J, Massague´ J. Kaplan FS, Xu M, Seemann P, Connor JM, Glaser DL, Car- 2001. The TGF b receptor activation process: An inhib- roll L, Delai P, Fastnacht-Urban E, Forman SJ, Gillessen- itor- to substrate-binding switch. Mol Cell 8: 671–682. Kaesbach G, et al. 2009. Classic and atypical fibrodyspla- Inui M, Manfrin A, Mamidi A, Martello G, Morsut L, Soligo sia ossificans progressiva (FOP) phenotypes are caused S, Enzo E, Moro S, Polo S, Dupont S, et al. 2011. USP15 by mutations in the bone morphogenetic protein (BMP) is a deubiquitylating for receptor-activated type I receptor ACVR1. Hum Mutat 30: 379–390. SMADs. Nat Cell Biol 13: 1368–1375. Karbiener M, Neuhold C, Opriessnig P,Prokesch A, Bogner- Ishida W, Hamamoto T, Kusanagi K, Yagi K, Kawabata M, Strauss JG, Scheideler M. 2011. MicroRNA-30c promotes Takehara K, Sampath TK, Kato M, Miyazono K. 2000. human differentiation and co-represses PAI-1 Smad6 is a Smad1/5-induced Smad inhibitor. Charac- and ALK2. RNA Biol 8: 850–860. terization of bone morphogenetic protein-responsive el- Kavsak P, Rasmussen RK, Causing CG, Bonni S, Zhu H, ement in the mouse Smad6 promoter. J Biol Chem 275: Thomsen GH, Wrana JL. 2000. Smad7 binds to Smurf2 6075–6079. to form an E3 ubiquitin ligase that targets the TGFb Jadrich JL, O’Connor MB, Coucouvanis E. 2006. The TGF b receptor for degradation. Mol Cell 6: 1365–1375. activated kinase TAK1 regulates vascular development in Keklikoglou I, Koerner C, Schmidt C, Zhang JD, Heckmann vivo. Development 133: 1529–1541. D, Shavinskaya A, Allgayer H, Guckel B, Fehm T, Schnee- Jin W,Kim BC, TognonC, Lee HJ, Patel S, Lannon CL, Maris weiss A, et al. 2012. MicroRNA-520/373 family functions JM, Triche TJ, Sorensen PH, Kim SJ. 2005. The ETV6- as a tumor suppressor in estrogen receptor negative breast NTRK3 chimeric tyrosine kinase suppresses TGF-b sig- cancer by targeting NF-kB and TGF-b signaling path- naling by inactivating the TGF-b type II receptor. Proc ways. Oncogene 31: 4150–4163. Natl Acad Sci 102: 16239–16244. Kim SI, Kwak JH, Na HJ, Kim JK, Ding Y, Choi ME. 2009. Jin Q, Ding W, Mulder KM. 2007a. Requirement for the Transforming growth factor-b (TGF-b1) activates TAK1 dynein light chain km23-1 in a Smad2-dependent trans- via TAB1-mediated autophosphorylation, independent forming growth factor-b signaling pathway. J Biol Chem of TGF-b receptor kinase activity in mesangial cells. J 282: 19122–19132. Biol Chem 284: 22285–22296. Jin W, Yun C, Kim HS, Kim SJ. 2007b. TrkC binds to the Kirkbride KC, Townsend TA, Bruinsma MW, Barnett JV, bone morphogenetic protein type II receptor to suppress Blobe GC. 2008. Bone morphogenetic proteins signal bone morphogenetic protein signaling. Cancer Res 67: through the transforming growth factor-b type III recep- 9869–9877. tor. J Biol Chem 283: 7628–7637.

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TGF-b Family Receptors

Kirsch T, Sebald W, Dreyer MK. 2000. Crystal structure of associated with a TGFBR2 mutation. Nat Clin Pract Car- the BMP-2-BRIA ectodomain complex. Nat Struct Biol 7: diovasc Med 4: 167–171. 492–496. Lewis KA, Gray PC, Blount AL, MacConell LA, Wiater E, Knelson EH, Gaviglio AL, Tewari AK, Armstrong MB, Bilezikjian LM, Vale W. 2000. Betaglycan binds inhibin Mythreye K, Blobe GC. 2013. Type III TGF-b receptor and can mediate functional antagonism of activin signal- promotes FGF2-mediated neuronal differentiation in ling. Nature 404: 411–414. neuroblastoma. J Clin Invest 123: 4786–4798. Li L, Liu YX, Guo Y, Liu B, Zhao YR, Li P, Song FJ, Zheng Kotzsch A, Nickel J, Seher A, Heinecke K, van Geersdaele L, H, Yu JP, Song TQ, et al. 2015. Regulatory MiR-148a- Herrmann T, Sebald W, Mueller TD. 2008. Structure ACVR1/BMP circuit defines a cancer stem cell-like ag- analysis of bone morphogenetic protein-2 type I receptor gressive subtype of hepatocellular carcinoma. Hepatology complexes reveals a mechanism of receptor inactivation 61: 574–584. in juvenile polyposis syndrome. J Biol Chem 283: 5876– Lin M, Sutherland DR, Horsfall W, Totty N, Yeo E, Nayar R, 5887. Wu XF, Schuh AC. 2002. Cell surface antigen CD109 Kovacs RJ, Maldonado G, Azaro A, Fernandez MS, Romero is a novel member of the a2 macroglobulin/C3, C4, FL, Sepulveda-Sanchez JM, Corretti M, Carducci M, Do- C5 family of thioester-containing proteins. Blood 99: lan M, Gueorguieva I, et al. 2015. Cardiac safety of TGF-b 1683–1691. receptor I kinase inhibitor LY2157299 monohydrate in Lin HK, Bergmann S, Pandolfi PP. 2004. Cytoplasmic PML cancer patients in a first-in-human dose study. Cardio- function in TGF-b signalling. Nature 431: 205–211. vasc Toxicol 15: 309–323. Liu XJ, Yue JB, Frey RS, Zhu QC, Mulder KM. 1998. Trans- Kowanetz M, Valcourt U, Bergstro¨m R, Heldin CH, Mous- forming growth factor b signaling through smad1 in hu- takas A. 2004. Id2 and Id3 define the potency of cell man breast cancer cells. Cancer Res 58: 4752–4757. proliferation and differentiation responses to transform- Liu C, Xu P, Lamouille S, Xu J, Derynck R. 2009a. TACE- ing growth factor b and bone morphogenetic protein. mediated ectodomain shedding of the type I TGF-b re- Mol Cell Biol 24: 4241–4254. ceptor downregulates TGF-b signaling. Mol Cell 35: 26– Kowanetz M, Lo¨nn P,Vanlandewijck M, Kowanetz K, Heldin 36. CH, Moustakas A. 2008. TGFb induces SIK to negatively Liu IM, Schilling SH, Knouse KA, Choy L, Derynck R, Wang regulate type I receptor kinase signaling. J Cell Biol 182: XF. 2009b. TGFb-stimulated Smad1/5 phosphorylation 655–662. requires the ALK5 L45 loop and mediates the pro-migra- Kwak JH, Kim SI, Kim JK, Choi ME. 2008. BAT3 interacts tory TGFb switch. EMBO J 28: 88–98. with transforming growth factor-b (TGF-b) receptors Liu JQ, Liao S, Diop-Frimpong B, Chen W,Goel S, Naxerova and enhances TGF-b1-induced type I collagen expres- K, Ancukiewicz M, Boucher Y,Jain RK, Xu L. 2012. TGF- sion in mesangial cells. J Biol Chem 283: 19816–19825. b blockade improves the distribution and efficacy of ther- Lawler S, Feng XH, Chen RH, Maruoka EM, Turck CW, apeutics in breast carcinoma by normalizing the tumor stroma. Proc Natl Acad Sci 109: 16618–16623. Griswold-Prenner I, Derynck R. 1997. The type II trans- forming growth factor-b receptor autophosphorylates Liu WJ, Li XL, Zhao YS, Meng XM, Wan C, Yang BX, Lan not only on serine and threonine but also on tyrosine HY, Lin HY, Xia Y. 2013. Dragon (repulsive guidance residues. J Biol Chem 272: 14850–14859. molecule RGMb) inhibits E-cadherin expression and in- duces apoptosis in renal tubular epithelial cells. J Biol Lebrin F, Goumans MJ, Jonker L, Carvalho RL, Valdimars- Chem 288: 31528–31539. dottir G, Thorikay M, Mummery C, Arthur HM, ten Dijke P.2004. Endoglin promotes endothelial cell prolif- Liu S, Nheu T, Luwor R, Nicholson SE, Zhu HJ. 2015. eration and TGF-b/ALK1 signal transduction. EMBO J SPSB1, a novel negative regulator of the transforming 23: 4018–4028. growth factor-b signaling pathway targeting the type II receptor. J Biol Chem 290: 17894–17908. Lee MK, Pardoux C, Hall MC, Lee PS, Warburton D, Qing J, ´ Smith SM, Derynck R. 2007. TGF-b activates Erk MAP Lo RS, Chen YG, Shi Y, Pavletich NP,Massague J. 1998. The L3 loop: A structural motif determining specific interac- kinase signalling through direct phosphorylation of tions between SMAD proteins and TGF-b receptors. ShcA. EMBO J 26: 3957–3967. EMBO J 17: 996–1005. Lee NY, Ray B, How T, Blobe GC. 2008. Endoglin promotes Loeys BL, Chen J, Neptune ER, Judge DP, Podowski M, transforming growth factor b-mediated Smad 1/5/8 sig- Holm T, Meyers J, Leitch CC, Katsanis N, Sharifi N, naling and inhibits endothelial cell migration through its et al. 2005. A syndrome of altered cardiovascular, cranio- association with GIPC. J Biol Chem 283: 32527–32533. facial, neurocognitive and skeletal development caused Lee NY,Kirkbride KC, Sheu RD, Blobe GC. 2009. The trans- by mutations in TGFBR1 or TGFBR2. Nat Genet 37: forming growth factor- b type III receptor mediates dis- 275–281. tinct subcellular trafficking and downstream signaling of Loeys BL, Schwarze U, Holm T,Callewaert BL, Thomas GH, activin-like kinase (ALK)3 and ALK6 receptors. Mol Biol Pannu H, De Backer JF,Oswald GL, Symoens S, Manouv- Cell 20: 4362–4370. rier S, et al. 2006. Aneurysm syndromes caused by mu- Lee-Hoeflich ST, Causing CG, Podkowa M, Zhao X, Wrana tations in the TGF-b receptor. N Engl J Med 355: 788– JL, Attisano L. 2004. Activation of LIMK1 by binding to 798. the BMP receptor, BMPRII, regulates BMP-dependent Lo¨nn P,Vanlandewijck M, Raja E, Kowanetz M, Watanabe Y, dendritogenesis. EMBO J 23: 4792–4801. Kowanetz K, Vasilaki E, Heldin CH, Moustakas A. 2012. LeMaire SA, Pannu H, Tran-Fadulu V,Carter SA, Coselli JS, Transcriptional induction of salt-inducible kinase 1 by Milewicz DM. 2007. Severe aortic and arterial aneurysms transforming growth factor b leads to negative regulation

Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a022053 27 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press

C.-H. Heldin and A. Moustakas

of type I receptor signaling in cooperation with the mains required for high affinity TGF-b binding: Proteo- Smurf2 ubiquitin ligase. J Biol Chem 287: 12867–12878. lytic cleavage separates the domains and inactivates the Lo´pez-Casillas F, Cheifetz S, Doody J, Andres JL, Lane WS, neutralizing activity of the soluble receptor. Biochemistry Massague´ J. 1991. Structure and expression of the mem- 48: 11755–11765. brane proteoglycan betaglycan, a component of the TGF- Meng Q, Lux A, Holloschi A, Li J, Hughes JM, Foerg T, b receptor system. Cell 67: 785–795. McCarthy JE, Heagerty AM, Kioschis P, Hafner M, Lo´pez-Casillas F, Wrana JL, Massague´ J. 1993. Betaglycan et al. 2006. Identification of Tctex2b, a novel dynein light presents ligand to the TGF-b signaling receptor. Cell chain family member that interacts with different trans- 73: 1435–1444. forming growth factor-b receptors. J Biol Chem 281: Lo´pez-Casillas F, Payne HM, Andres JL, Massague´ J. 1994. 37069–37080. Betaglycan can act as a dual modulatorof TGF-b access to Mestdagh P,Bostrom AK, Impens F,Fredlund E, VanPeer G, signaling receptors: Mapping of ligand binding and GAG De Antonellis P,von Stedingk K, Ghesquiere B, Schulte S, attachment sites. J Cell Biol 124: 557–568. Dews M, et al. 2010. The miR-17–92 MicroRNA cluster Loveland KL, Bakker M, Meehan T, Christy E, von Schon- regulates multiple components of the TGF-b pathway in feldt V, Drummond A, de Kretser D. 2003. Expression of neuroblastoma. Mol Cell 40: 762–773. Bambi is widespread in juvenile and adult rat tissues and Meyer AE, Gatza CE, How T, Starr M, Nixon AB, Blobe GC. is regulated in male germ cells. Endocrinology 144: 4180– 2014. Role of TGF-b receptor III localization in polarity 4186. and breast cancer progression. Mol Biol Cell 25: 2291– Luo K. 2004. Ski and SnoN: Negative regulators of TGF-b 2304. signaling. Curr Opin Genet Dev 14: 65–70. Mitchell H, Choudhury A, Pagano RE, Leof EB. 2004. Li- Luo KX, Lodish HF.1997. Positive and negative regulation of gand-dependent and -independent transforming growth type II TGFb receptor signal transduction by autophos- factor-b receptor recycling regulated by clathrin-mediat- phorylation on multiple serine residues. EMBO J 16: ed endocytosis and Rab11. Mol Biol Cell 15: 4166–4178. 1970–1981. Miyazono K, Kamiya Y, Morikawa M. 2010. Bone morpho- Luo T,Cui SJ, Bian CJ, Yu XC. 2014. Crosstalk between TGF- genetic protein receptors and signal transduction. J Bio- b/Smad3 and BMP/BMPR2 signaling pathways via chem 147: 35–51. miR-17–92 cluster in carotid artery restenosis. Mol Cell Mizuguchi T, Collod-Beroud G, Akiyama T, Abifadel M, Biochem 389: 169–176. Harada N, Morisaki T, Allard D, Varret M, Claustres M, Machado RD, Pauciulo MW, Thomson JR, Lane KB, Mor- Morisaki H, et al. 2004. Heterozygous TGFBR2 muta- gan NV, Wheeler L, Phillips JA III, Newman J, Williams tions in Marfan syndrome. Nat Genet 36: 855–860. D, Galie N, et al. 2001. BMPR2 haploinsufficiency as the Mohammad KS, Javelaud D, Fournier PGJ, Niewolna M, inherited molecular mechanism for primary pulmonary McKenna CR, Peng XH, Duong V, Dunn LK, Mauviel hypertension. Am J Hum Genet 68: 92–102. A, Guise TA. 2011. TGF-b-RI kinase inhibitor SD-208 Maeda S, Hayashi M, Komiya S, Imamura T, Miyazono K. reduces the development and progression of melanoma 2004. Endogenous TGF-b signaling suppresses matura- bone metastases. Cancer Res 71: 175–184. tion of osteoblastic mesenchymal cells. EMBO J 23: 552– 563. Moustakas A, Heldin CH. 2005. Non-Smad TGF-b signals. J Cell Sci 118: 3573–3584. Manning G, Whyte DB, Martinez R, Hunter T, Sudarsanam S. 2002. The protein kinase complement of the human Moustakas A, Heldin CH. 2009. The regulation of TGFb genome. Science 298: 1912–1934. signal transduction. Development 136: 3699–3714. Mao SS, Li HQ, Sun Q, Zen K, Zhang CY,Li L. 2014. miR-17 Moustakas A, Lin HY, Henis YI, Plamondon J, O’Connor- regulates the proliferation and differentiation of the neu- McCourt MD, Lodish HF. 1993. The transforming ral precursor cells during mouse corticogenesis. FEBS J growth factor b receptors types I, II, and III form het- 281: 1144–1158. ero-oligomeric complexes in the presence of ligand. J Biol Martello G, Zacchigna L, Inui M, Montagner M, Adorno M, Chem 268: 22215–22218. Mamidi A, Morsut L, Soligo S, Tran U, Dupont S, et al. Mu Y, Sundar R, Thakur N, Ekman M, Gudey SK, Yakymo- 2007. MicroRNA control of Nodal signalling. Nature 449: vych M, Hermansson A, Dimitriou H, Bengoechea- 183–188. Alonso MT, Ericsson J, et al. 2011. TRAF6 ubiquitinates Massague´ J. 2012. TGFb signalling in context. Nat Rev Mol TGFb type I receptor to promote its cleavage and nuclear Cell Biol 13: 616–630. translocation in cancer. Nat Commun 2: 330. Massague´ J, Seoane J, Wotton D. 2005. Smad transcription Mura M, Cappato S, Giacopelli F, Ravazzolo R, Bocciardi R. 0 factors. Genes Dev 19: 2783–2810. 2012. The role of the 3 UTR region in the regulation of / McAllister KA, Grogg KM, Johnson DW, Gallione CJ, Bald- the ACVR1 Alk-2 . PLoS ONE 7: e50958. win MA, Jackson CE, Helmbold EA, Markel DS, McKin- Murphy SJ, Dore JJ, Edens M, Coffey RJ, Barnard JA, Mitch- non WC, Murrell J, et al. 1994. Endoglin, a TGF-b bind- ell H, Wilkes M, Leof EB. 2004. Differential trafficking of ing protein of endothelial cells, is the gene for hereditary transforming growth factor-b receptors and ligand in haemorrhagic telangiectasia type 1. Nat Genet 8: 345– polarized epithelial cells. Mol Biol Cell 15: 2853–2862. 351. Murphy SJ, Shapira KE, Henis YI, Leof EB. 2007. A unique Mendoza V,Vilchis-Landeros MM, Mendoza-Hernandez G, element in the cytoplasmic tail of the type II transform- Huang T, Villarreal MM, Hinck AP, Lopez-Casillas F, ing growth factor-b receptor controls basolateral delivery. Montiel JL. 2009. Betaglycan has two independent do- Mol Biol Cell 18: 3788–3799.

28 Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a022053 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press

TGF-b Family Receptors

Mythreye K, Blobe GC. 2009. The type III TGF-b receptor glycan processing and endocytosis. Science 306: 120– regulates epithelial and cancer cell migration through b- 124. arrestin2-mediated activation of Cdc42. Proc Natl Acad Penheiter SG, Mitchell H, Garamszegi N, Edens M, Dore JJ Sci 106: 8221–8226. Jr, Leof EB. 2002. Internalization-dependent and -inde- Nagaoka T, Karasawa H, Castro NP, Rangel MC, Salomon pendent requirements for transforming growth factor b DS, Bianco C. 2012. An evolving web of signaling net- receptor signaling via the Smad pathway. Mol Cell Biol 22: works regulated by Cripto-1. Growth Factors 30: 13–21. 4750–4759. Nakao A, Afrakhte M, More´n A, Nakayama T, Christian JL, Penheiter SG, Singh RD, Repellin CE, Wilkes MC, Edens M, Heuchel R, Itoh S, Kawabata M, Heldin NE, Heldin CH, Howe PH, Pagano RE, Leof EB. 2010. Type II transform- et al. 1997. Identification of Smad7, a TGFb-inducible ing growth factor-b receptor recycling is dependent upon antagonist of TGF-b signalling. Nature 389: 631–635. the clathrin adaptor protein Dab2. Mol Biol Cell 21: Neil JR, Tian M, Schiemann WP.2009. X-linked inhibitor of 4009–4019. apoptosis protein and its E3 ligase activity promote Peterson RS, Andhare RA, Rousche KT, Knudson W, Wang transforming growth factor-b-mediated nuclear factor- W, Grossfield JB, Thomas RO, Hollingsworth RE, Knud- kB activation during breast cancer progression. J Biol son CB. 2004. CD44 modulates Smad1 activation in the Chem 284: 21209–21217. BMP-7 signaling pathway. J Cell Biol 166: 1081–1091. Neptune ER, Frischmeyer PA, Arking DE, Myers L, Bunton Petritsch C, Beug H, Balmain A, Oft M. 2000. TGF-b inhib- TE, Gayraud B, Ramirez F, Sakai LY, Dietz HC. 2003. its p70 S6 kinase via protein phosphatase 2A to induce G1 Dysregulation of TGF-b activation contributes to path- arrest. Genes Dev 14: 3093–3101. ogenesis in Marfan syndrome. Nat Genet 33: 407–411. Porsch H, Mehic M, Olofsson B, Heldin P,Heldin CH. 2014. Nieminen TT, Abdel-Rahman WM, Ristimaki A, Lappalai- Platelet-derived growth factor b-receptor, transforming nen M, Lahermo P,Mecklin JP,Jarvinen HJ, Peltomaki P. growth factor b type I receptor, and CD44 protein mod- 2011. BMPR1A mutations in hereditary nonpolyposis ulate each other’s signaling and stability. J Biol Chem 289: colorectal cancer without mismatch repair deficiency. 19747–19757. Gastroenterology 141: E23–E26. Qiu T, Wu X, Zhang F, Clemens TL, Wan M, Cao X. 2010. b Nohe A, Hassel S, Ehrlich M, Neubauer F, Sebald W, Henis TGF- type II receptor phosphorylates PTH receptor to YI, Knaus P. 2002. The mode of bone morphogenetic integrate bone remodelling signalling. Nat Cell Biol 12: 224–234. protein (BMP) receptor oligomerization determines dif- ferent BMP-2 signaling pathways. J Biol Chem 277: 5330– Radaev S, Zou ZC, Huang T, Lafer EM, Hinck AP, Sun PD. 5338. 2010. Ternary complex of transforming growth factor-b 1 reveals isoform-specific ligand recognition and receptor Onichtchouk D, Chen YG, Dosch R, Gawantka V,Dellus H, recruitment in the superfamily. J Biol Chem 285: 14806– Massague´ J, Niehrs C. 1999. Silencing of TGF-b signal- 14814. ling by the pseudoreceptor BAMBI. Nature 401: 480– 485. Ray BN, Lee NY, How T, Blobe GC. 2010. ALK5 phosphor- ylation of the endoglin cytoplasmic domain regulates Oved S, Mosesson Y, Zwang Y, Santonico E, Shtiegman K, Smad1/5/8 signaling and endothelial cell migration. Marmor MD, Kochupurakkal BS, Katz M, Lavi S, Cesar- Carcinogenesis 31: 435–441. eni G, et al. 2006. Conjugation to Nedd8 instigates ubiq- uitylation and down-regulation of activated receptor ty- Razani B, Zhang XL, Bitzer M, von Gersdorff G, Bo¨ttinger rosine kinases. J Biol Chem 281: 21640–21651. EP, Lisanti MP. 2001. Caveolin-1 regulates transforming growth factor (TGF)-b/SMAD signaling through an in- Ozdamar B, Bose R, Barrios-Rodiles M, Wang HR, Zhang Y, teraction with the TGF-b type I receptor. J Biol Chem 276: Wrana JL. 2005. Regulation of the polarity protein Par6 6727–6738. by TGFb receptors controls epithelial cell plasticity. Sci- Rechtman MM, Nakaryakov A, Shapira KE, Ehrlich M, He- ence 307: 1603–1609. nis YI. 2009. Different domains regulate homomeric and Pannu H, Fadulu VT,Chang J, Lafont A, Hasham SN, Sparks heteromeric complex formation among type I and type II E, Giampietro PF, Zaleski C, Estrera AL, Safi HJ, et al. transforming growth factor-b receptors. J Biol Chem 284: 2005. Mutations in transforming growth factor-b recep- 7843–7852. tor type II cause familial thoracic aortic aneurysms and Rodon J, Carducci M, Sepulveda-Sanchez JM, Azaro A, dissections. Circulation 112: 513–520. Calvo E, Seoane J, Brana I, Sicart E, Gueorguieva I, Clev- Parikh VN, Jin RC, Rabello S, Gulbahce N, White K, Hale A, erly A, et al. 2015a. Pharmacokinetic, pharmacodynamic Cottrill KA, Shaik RS, WaxmanAB, Zhang YY,et al. 2012. and biomarker evaluation of transforming growth factor- MicroRNA-21 integrates pathogenic signaling to control b receptor I kinase inhibitor, galunisertib, in phase 1 results of a network bioinfor- study in patients with advanced cancer. Invest New Drugs matics approach. Circulation 125: 1520–1531. 33: 357–370. Park SO, Lee YJ, Seki T, Hong KH, Fliess N, Jiang Z, Park A, Rodon J, Carducci MA, Sepulveda-Sanchez JM, Azaro A, Wu X, Kaartinen V, Roman BL, et al. 2008. ALK5- and Calvo E, Seoane J, Brana I, Sicart E, Gueorguieva I, Clev- TGFBR2-independent role of ALK1 in the pathogenesis erly AL, et al. 2015b. First-in-human dose study of the of hereditary hemorrhagic telangiectasia type 2. Blood novel transforming growth factor-b receptor I kinase in- 111: 633–642. hibitor LY2157299 monohydrate in patients with ad- Partridge EA, Le Roy C, Di Guglielmo GM, Pawling J, vanced cancer and glioma. Clin Cancer Res 21: 553–560. Cheung P, Granovsky M, Nabi IR, Wrana JL, Dennis Rudini N, Felici A, Giampietro C, Lampugnani M, Corada JW. 2004. Regulation of cytokine receptors by Golgi N- M, Swirsding K, Garre M, Liebner S, Letarte M, ten Dijke

Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a022053 29 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press

C.-H. Heldin and A. Moustakas

P, et al. 2008. VE-cadherin is a critical endothelial regu- Seong HA, Jung H, Ha H. 2007. NM23-H1 tumor suppres- lator of TGF-b signalling. EMBO J 27: 993–1004. sor physically interacts with serine-threonine kinase re- Saetrom P,Biesinger J, Li SM, Smith D, Thomas LF,Majzoub ceptor-associated protein, a transforming growth factor- K, Rivas GE, Alluin J, Rossi JJ, Krontiris TG, et al. 2009. A b (TGF-b) receptor-interacting protein, and negatively risk variant in an miR-125b binding site in BMPR1B is regulates TGF-b signaling. J Biol Chem 282: 12075– associated with breast cancer pathogenesis. Cancer Res 12096. 69: 7459–7465. Shi W, Sun C, He B, Xiong W, Shi X, Yao D, Cao X. 2004. Samad TA, Rebbapragada A, Bell E, Zhang Y, Sidis Y, Jeong GADD34-PP1c recruited by Smad7 dephosphorylates SJ, Campagna JA, Perusini S, Fabrizio DA, Schneyer AL, TGFb type I receptor. J Cell Biol 164: 291–300. et al. 2005. DRAGON, a bone morphogenetic protein co- Shi W,Chang C, Nie S, Xie S, Wan M, Cao X. 2007. Endofin receptor. J Biol Chem 280: 14122–14129. acts as a Smad anchor for receptor activation in BMP Sammar M, Stricker S, Schwabe GC, Sieber C, Hartung A, signaling. J Cell Sci 120: 1216–1224. Hanke M, Oishi I, Pohl J, Minami Y,Sebald W,et al. 2004. Shibuya H, Iwata H, Masuyama N, Gotoh Y, Yamaguchi K, Modulation of GDF5/BRI-b signalling through interac- Irie K, Matsumoto K, Nishida E, Ueno N. 1998. Role of tion with the tyrosine kinase receptor Ror2. Genes Cells 9: TAK1 and TAB1 in BMP signaling in early Xenopus de- 1227–1238. velopment. EMBO J 17: 1019–1028. Satow R, Kurisaki A, Chan TC, Hamazaki TS, Asashima M. Shim JH, Greenblatt MB, Xie M, Schneider MD, Zou W, 2006. Dullard promotes degradation and dephosphory- Zhai B, Gygi S, Glimcher LH. 2009. TAK1 is an essential lation of BMP receptors and is required for neural induc- regulator of BMP signalling in cartilage. EMBO J 28: tion. Dev Cell 11: 763–774. 2028–2041. Saunier EF, Akhurst RJ. 2006. TGF b inhibition for cancer Shore EM, Xu M, Feldman GJ, Fenstermacher DA, Cho TJ, therapy. Curr Cancer Drug Targets 6: 565–578. Choi IH, Connor JM, Delai P, Glaser DL, LeMerrer M, et al. 2006. A recurrent mutation in the BMP type I re- Scaffidi AK, Petrovic N, Moodley YP, Fogel-Petrovic M, ceptor ACVR1 causes inherited and sporadic fibrodyspla- Kroeger KM, Seeber RM, Eidne KA, Thompson PJ, sia ossificans progressiva. Nat Genet 38: 525–527. Knight DA. 2004. avb3 Integrin interacts with the trans- forming growth factor b (TGFb) type II receptor to po- Singh KK, Rommel K, Mishra A, Karck M, Haverich A, tentiate the proliferative effects of TGFb1 in living hu- Schmidtke J, Arslan-Kirchner M. 2006. TGFBR1 and TGFBR2 mutations in patients with features of Marfan man lung fibroblasts. J Biol Chem 279: 37726–37733. syndrome and Loeys–Dietz syndrome. Hum Mutat 27: Scherner O, Meurer SK, Tihaa L, Gressner AM, Weiskirchen 770–777. R. 2007. Endoglin differentially modulates antagonistic Siragam V,Rutnam ZJ, Yang WN, Fang L, Luo LL, Yang XL, transforming growth factor-b1 and BMP-7 signaling. J Li MH, Deng ZQ, Qian J, Peng C, et al. 2012. MicroRNA Biol Chem 282: 13934–13943. miR-98 inhibits tumor angiogenesis and invasion by tar- Schiemann WP, Rotzer D, Pfeifer WM, Levi E, Rai KR, geting activin receptor-like kinase-4 and matrix metal- Knaus P, Kadin ME. 2004. Transforming growth factor- loproteinase-11. Oncotarget 3: 1370–1385. b b (TGF- )-resistant B cells from chronic lymphocytic Sorensen LK, Brooke BS, Li DY, Urness LD. 2003. Loss of leukemia patients contain recurrent mutations in the sig- distinct arterial and venous boundaries in mice lacking nal sequence of the type I TGF-b receptor. Cancer Detect endoglin, a vascular-specific TGFb coreceptor. Dev Biol Prev 28: 57–64. 261: 235–250. Schwappacher R, Weiske J, Heining E, Ezerski V, Marom B, Sorrentino A, Thakur N, Grimsby S, Marcusson A, von Henis YI, Huber O, Knaus P. 2009. Novel crosstalk to Bulow V, Schuster N, Zhang S, Heldin CH, Landstro¨m BMP signalling: cGMP-dependent kinase I modulates M. 2008. The type I TGF-b receptor engages TRAF6 to BMP receptor and Smad activity. EMBO J 28: 1537– activate TAK1 in a receptor kinase-independent manner. 1550. Nat Cell Biol 10: 1199–1207. Sebald W, Nickel J, Zhang JL, Mueller TD. 2004. Molecular Souchelnytskyi S, ten Dijke P, Miyazono K, Heldin CH. recognition in bone morphogenetic protein (BMP)/re- 1996. Phosphorylation of Ser165 in TGF- b type I re- ceptor interaction. Biol Chem 385: 697–710. ceptor modulates TGF-b1-induced cellular responses. Sekiya T, Oda T, Matsuura K, Akiyama T. 2004. Transcrip- EMBO J 15: 6231–6240. tional regulation of the TGF-b pseudoreceptor BAMBI Souchelnytskyi S, Tamaki K, Engstro¨m U, Wernstedt C, ten by TGF-b signaling. Biochem Biophys Res Commun 320: Dijke P,Heldin CH. 1997. Phosphorylation of Ser465 and 680–684. Ser467 in the C terminus of Smad2 mediates interaction Senanayake U, Das S, Vesely P, Alzoughbi W, Frohlich LF, with Smad4 and is required for transforming growth fac- Chowdhury P, Leuschner I, Hoefler G, Guertl B. 2012. tor-b signaling. J Biol Chem 272: 28107–28115. miR-192, miR-194, miR-215, miR-200c and miR-141 are Spiekerkoetter E, Tian XF,Cai J, Hopper RK, Sudheendra D, downregulated and their common target ACVR2B is Li CYG, El-Bizri N, Sawada H, Haghighat R, Chan R, et al. strongly expressed in renal childhood neoplasms. Car- 2013. FK506 activates BMPR2 rescues endothelial dys- cinogenesis 33: 1014–1021. function, and reverses pulmonary hypertension. J Clin Seong HA, Jung H, Choi HS, Kim KT, Ha H. 2005. Regula- Invest 123: 3600–3613. tion of transforming growth factor-b signaling and Stenvers KL, Tursky ML, Harder KW, Kountouri N, Ama- PDK1 kinase activity by physical interaction between tayakul-Chantler S, Grail D, Small C, Weinberg RA, Size- PDK1 and serine-threonine kinase receptor-associated land AM, Zhu HJ. 2003. Heart and liver defects and re- protein. J Biol Chem 280: 42897–42908. duced transforming growth factor b2 sensitivity in

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TGF-b Family Receptors

transforming growth factor b type III receptor-deficient Valdimarsdo´ttir G, Goumans MJ, Itoh F,Itoh S, Heldin CH, embryos. Mol Cell Biol 23: 4371–4385. ten Dijke P.2006. Smad7 and protein phosphatase 1a are Su Y,Zhang L, Gao X, Meng F,WenJ, Zhou H, Meng A, Chen critical determinants in the duration of TGFb/ALK1 sig- YG. 2007. The evolutionally conserved activity of Dap- naling in endothelial cells. BMC Cell Biol 7: 16. per2 in antagonizing TGF-b signaling. FASEB J 21: 682– van Dinther M, Visser N, de Gorter DJJ, Doorn J, Goumans 690. MJ, de Boer J, ten Dijke P. 2010. ALK2 R206H mutation Subramanyam D, Lamouille S, Judson RL, Liu JY, Bucay N, linked to fibrodysplasia ossificans progressiva confers Derynck R, Blelloch R. 2011. Multiple targets of miR-302 constitutive activity to the BMP type I receptor and sen- and miR-372 promote reprogramming of human fibro- sitizes mesenchymal cells to BMP-induced dif- blasts to induced pluripotent stem cells. Nat Biotechnol ferentiation and bone formation. J Bone Miner Res 25: 29: 443–448. 1208–1215. Sun Q, Mao SS, Li HQ, Zen K, Zhang CY,Li L. 2013. Role of van Meeteren LA, Thorikay M, Bergqvist S, Pardali E, Gal- miR-17 family in the negative feedback loop of bone lo Stampino C, Hu-Lowe D, Goumans MJ, Ten Dijke morphogenetic protein signaling in neuron. PLoS ONE P. 2012. Anti-human activin receptor-like kinase 1 8: e83067. (ALK1) antibody attenuates bone morphogenetic pro- tein 9 (BMP9)-induced ALK1 signaling and inter- Suzuki E, Kim S, Cheung HK, Corbley MJ, Zhang X, Sun L, Shan F, Singh J, Lee WC, Albelda SM, et al. 2007. A novel feres with endothelial cell sprouting. J Biol Chem 287: 18551–18561. small-molecule inhibitor of transforming growth factor b type I receptor kinase (SM16) inhibits murine meso- Velasco S, Alvarez-Munoz P, Pericacho M, Dijke PT, Berna- thelioma tumor growth in vivo and prevents tumor re- beu C, Lopez-Novoa JM, Rodriguez-Barbero A. 2008. L- currence after surgical resection. Cancer Res 67: 2351– and S-endoglin differentially modulate TGFb1 signaling 2359. mediated by ALK1 and ALK5 in L6E9 myoblasts. J Cell Sci Tam BYY, Germain L, Philip A. 1998. TGF-b receptor ex- 121: 913–919. pression on human keratinocytes: A 150 kDa GPI-an- Wakefield LM, Hill CS. 2013. Beyond TGFb: Roles of other chored TGF-b1 binding protein forms a heteromeric TGFb superfamily members in cancer. Nat Rev Cancer complex with type I and type II receptors. J Cell Biochem 13: 328–341. 70: 573–586. Wang T, Li B-Y, Danielson PD, Shah PC, Rockwell S, Lech- Tang Q, Staub CM, Gao G, Jin Q, Wang Z, Ding W, Auri- leider RJ, Martin J, Manganaro T,Donahoe PK. 1996. The gemma RE, Mulder KM. 2002. A novel transforming immunophilin FKBP12 functions as a common inhibitor growth factor-b receptor-interacting protein that is also of the TGFb family type I receptors. Cell 86: 435–444. a light chain of the motor protein dynein. Mol Biol Cell Wang Q, Huang Z, Xue H, Jin C, Ju XL, Han JD, Chen Y-G. 13: 4484–4496. 2008. MicroRNA miR-24 inhibits erythropoiesis by tar- Taylor KR, Mackay A, Truffaux N, Butterfield YS, Morozova geting activin type I receptor ALK4. Blood 111: 588–595. O, Philippe C, Castel D, Grasso CS, Vinci M, Carvalho D, Wang B, Jha JC, Hagiwara S, McClelland AD, Jandeleit- et al. 2014. Recurrent activating ACVR1 mutations in Dahm K, Thomas MC, Cooper ME, Kantharidis P. diffuse intrinsic pontine glioma. Nat Genet 46: 457–461. 2014. Transforming growth factor-b 1-mediated renal Tazat K, Hector-Greene M, Blobe GC, Henis YI. 2015. fibrosis is dependent on the regulation of transforming TbRIII independently binds type I and type II TGF-b 1 expression by let-7b. Kidney Int receptors to inhibit TGF-b signaling. Mol Biol Cell 26: 85: 352–361. 3535–3545. Weis-Garcia F,Massague´ J. 1996. Complementation between ten Dijke P,Arthur HM. 2007. Extracellular control of TGFb kinase-defective and activation-defective TGF-b recep- signalling in vascular development and disease. Nat Rev tors reveals a novel form of receptor essen- Mol Cell Biol 8: 857–869. tial for signaling. EMBO J 15: 276–289. Thomson J, Machado R, Pauciulo M, Morgan N, Yacoub M, Wells RG, Gilboa L, Sun Y, Liu XD, Henis YI, Lodish HF. Corris P,McNeil K, Loyd J, Nichols W,Trembath R. 2001. 1999. Transforming growth factor-b induces formation Familial and sporadic primary pulmonary hypertension of a dithiothreitol-resistant type I/type II receptor com- is caused by BMPR2 gene mutations resulting in hap- plex in live cells. J Biol Chem 274: 5716–5722. loinsufficiency of the bone morphogenetic protein type Wiater E, Harrison CA, Lewis KA, Gray PC, Vale WW.2006. II receptor. J Heart Lung Transplant 20: 149. Identification of distinct inhibin and transforming Tsang M, Kim R, de Caestecker MP, Kudoh T, Roberts AB, growth factor b-binding sites on betaglycan: Functional Dawid IB. 2000. Zebrafish nma is involved in TGFb fam- separation of betaglycan co-receptor actions. J Biol Chem ily signaling. Genesis 28: 47–57. 281: 17011–17022. Tsukazaki T, Chiang TA, Davison AF, Attisano L, Wrana JL. Wong WK, Knowles JA, Morse JH. 2005. Bone morphoge- 1998. SARA, a FYVE domain protein that recruits Smad2 netic protein receptor type II C-terminus interacts with to the TGFb receptor. Cell 95: 779–791. c-Src: Implication for a role in pulmonary arterial hyper- Uhl M, Aulwurm S, Wischhusen J, WeilerM, Ma JY,Almirez tension. Am J Respir Cell Mol Biol 33: 438–446. R, Mangadu R, Liu YW, Platten M, Herrlinger U, et al. Wrana JL, Attisano L, Wieser R, Ventura F,Massague´ J. 1994. 2004. SD-208, a novel transforming growth factor b re- Mechanism of activation of the TGF-b receptor. Nature ceptor I kinase inhibitor, inhibits growth and invasive- 370: 341–347. ness and enhances immunogenicity of murine and hu- Wrighton KH, Lin X, Feng X-H. 2008. Critical regulation of man glioma cells in vitro and in vivo. Cancer Res 64: TGFb signaling by Hsp90. Proc Natl Acad Sci 105: 9244– 7954–7961. 9249.

Advanced Online Article. Cite this article as Cold Spring Harb Perspect Biol doi: 10.1101/cshperspect.a022053 31 Downloaded from http://cshperspectives.cshlp.org/ on September 28, 2021 - Published by Cold Spring Harbor Laboratory Press

C.-H. Heldin and A. Moustakas

Wrighton KH, Lin X, Feng XH. 2009a. Phospho-control of Yao DY, Ehrlich M, Henis YI, Leof EB. 2002. Transforming TGF-b superfamily signaling. Cell Res 19: 8–20. growth factor-b receptors interact with AP2 by direct Wrighton KH, Lin X, Yu PB, Feng XH. 2009b. Transforming binding to b2 subunit. Mol Biol Cell 13: 4001–4012. growth factor b can stimulate Smad1 phosphorylation Ye G, Fu GD, Cui SY, Zhao SF, Bernaudo S, Bai Y, Ding YF, independently of bone morphogenic protein receptors. Zhang YO, Yang BB, Peng C. 2011. MicroRNA 376c en- J Biol Chem 284: 9755–9763. hances ovarian cancer cell survival by targeting activin Wu LY,Derynck R. 2009. Essential role of TGF-b signaling in receptor-like kinase 7: Implications for chemoresistance. glucose-induced cell hypertrophy. Dev Cell 17: 35–48. J Cell Sci 124: 359–368. Yi JY, Shin I, Arteaga CL. 2005. Type I transforming growth Wu S, Lin Y, Xu D, Chen J, Shu M, Zhou Y, Zhu W, Su X, factor b receptor binds to and activates phosphatidylino- Zhou Y, Qiu P, et al. 2012. MiR-135a functions as a se- sitol 3-kinase. J Biol Chem 280: 10870–10876. lective killer of malignant glioma. Oncogene 31: 3866– 3874. Yin XQ, Murphy SJ, Wilkes MC, Ji Y, Leof EB. 2013. Retro- mer maintains basolateral distribution of the type II Xi Q, He W, Zhang XH, Le HV,Massague J. 2008. Genome- TGF-b receptor via the recycling endosome. Mol Biol wide impact of the BRG1 SWI/SNF chromatin remod- Cell 24: 2285–2298. eler on the transforming growth factor b transcriptional Yingling JM, Blanchard KL, Sawyer JS. 2004. Development program. J Biol Chem 283: 1146–1155. of TGF-b signalling inhibitors for cancer therapy. Nat Xia Y, Yu PB, Sidis Y, Beppu H, Bloch KD, Schneyer AL, Lin Rev Drug Discov 3: 1011–1022. HY.2007. Repulsive guidance molecule RGMa alters uti- You HJ, Bruinsma MW, How T, Ostrander JH, Blobe GC. lization of bone morphogenetic protein (BMP) type II 2007. The type III TGF-b receptor signals through both receptors by BMP2 and BMP4. J Biol Chem 282: 18129– Smad3 and the p38 MAP kinase pathways to contribute 18140. to inhibition of cell proliferation. Carcinogenesis 28: Xu J, Wang AHJ, Oses-Prieto J, Makhijani K, Katsuno Y, Pei 2491–2500. M, Yan LL, Zheng YG, Burlingame A, Bru¨ckner K, et al. Yumoto K, Thomas PS, Lane J, Matsuzaki K, Inagaki M, 2013. Arginine methylation initiates BMP-induced Smad Ninomiya-Tsuji J, Scott GJ, Ray MK, Ishii M, Maxson signaling. Mol Cell 51: 5–19. R, et al. 2013. TGF-b-activated kinase 1 (Tak1) mediates Yakymovych I, Yakymovych M, Zang G, Mu Y, Bergh A, agonist-induced Smad activation and linker region phos- Landstro¨m M, Heldin CH. 2015. CIN85 modulates phorylation in embryonic craniofacial neural crest-de- TGFb signaling by promoting the presentation of rived cells. J Biol Chem 288: 13467–13480. TGFb receptors on the cell surface. J Cell Biol 210: Zeng Y, Qu XB, Li HL, Huang S, Wang SH, Xu QL, Lin RZ, 319–332. Han Q, Li J, Zhao RC. 2012. MicroRNA-100 regulates Yamashita H, ten Dijke P, Franze´n P, Miyazono K, Heldin osteogenic differentiation of human adipose-derived CH. 1994. Formation of hetero-oligomeric complexes of mesenchymal stem cells by targeting BMPR2. FEBS Lett type I and type II receptors for transforming growth fac- 586: 2375–2381. tor-b. J Biol Chem 269: 20172–20178. Zhang W, Jiang Y, Wang Q, Ma X, Xiao Z, Zuo W, Fang X, Yamashita M, Fatyol K, Jin C, Wang X, Liu Z, Zhang YE. Chen YG. 2009a. Single-molecule imaging reveals trans- 2008. TRAF6 mediates Smad-independent activation of forming growth factor-b-induced type II receptor dime- JNK and p38 by TGF-b. Mol Cell 31: 918–924. rization. Proc Natl Acad Sci 106: 15679–15683. Yan YT, Liu JJ, Luo Y, E C, Haltiwanger RS, Abate-Shen C, Zhang Y,Li X, Qi J, WangJ, Liu X, Zhang H, Lin SC, Meng A. Shen MM. 2002. Dual roles of Cripto as a ligand and 2009b. Rock2 controls TGFb signaling and inhibits me- coreceptor in the nodal signaling pathway. Mol Cell Biol soderm induction in zebrafish embryos. J Cell Sci 122: 2197–2207. 22: 4439–4449. Zhang M, Kleber S, Rohrich M, Timke C, Han N, Tuetten- Yan X, Lin Z, Chen F, Zhao X, Chen H, Ning Y, Chen YG. berg J, Martin-Villalba A, Debus J, Peschke P,Wirkner U, 2009. Human BAMBI cooperates with Smad7 to inhibit et al. 2011. Blockade of TGF-b signaling by the TGFb R-I transforming growth factor-b signaling. J Biol Chem 284: kinase inhibitor LY2109761 enhances radiation response 30097–30104. and prolongs survival in glioblastoma. Cancer Res 71: YanX, Zhang J, Pan L, WangP,Xue H, Zhang L, Gao X, Zhao 7155–7167. X, Ning Y, Chen YG. 2011. TSC-22 promotes transform- Zhang L, Zhou F, Drabsch Y, Gao R, Snaar-Jagalska BE, ing growth factor b-mediated cardiac myofibroblast dif- Mickanin C, Huang H, Sheppard KA, Porter JA, Lu ferentiation by antagonizing Smad7 activity. Mol Cell Biol CX, et al. 2012. USP4 is regulated by AKT phosphoryla- 31: 3700–3709. tion and directly deubiquitylates TGF-b type I receptor. Yan GJ, Zhang LX, Fang T, Zhang Q, Wu SG, Jiang Y, Sun Nat Cell Biol 14: 717–726. HX, Hu YL. 2012. MicroRNA-145 suppresses mouse Zhang L, Zhou FF, de Vinuesa AG, de Kruijf EM, Mesker granulosa cell proliferation by targeting activin receptor WE, Hui L, Drabsch Y,Li YH, Bauer A, Rousseau A, et al. IB. FEBS Lett 586: 3263–3270. 2013a. TRAF4 promotes TGF-b receptor signaling and YangH, Fang F,Chang RM, YangLY.2013. MicroRNA-140– drives breast cancer metastasis. Mol Cell 51: 559–572. 5p suppresses tumor growth and metastasis by targeting Zhang Q, Sun HX, Jiang Y,Ding LJ, Wu SG, Fang T, Yan GJ, transforming growth factor b receptor 1 and fibroblast Hu YL. 2013b. MicroRNA-181a suppresses mouse gran- growth factor 9 in hepatocellular carcinoma. Hepatology ulosa cell proliferation by targeting activin receptor IIA. 58: 205–217. PLoS ONE 8: 59667.

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TGF-b Family Receptors

Zhong ZJ, Carroll KD, Policarpio D, Osborn C, Gregory M, Zumbrennen-Bullough KB, Wu QF, Core AB, Canali S, Bassi R, Jimenez X, Prewett M, Liebisch G, Persaud K, Chen WJ, Theurl I, Meynard D, Babitt JL. 2014. Micro- et al. 2010. Anti-transforming growth factor b receptor II RNA-130a is up-regulated in mouse liver by iron defi- antibody has therapeutic efficacy against primary tumor ciency and targets the bone morphogenetic protein growth and metastasis through multieffects on cancer, (BMP) receptor ALK2 to attenuate BMP signaling stroma, and immune cells. Clin Cancer Res 16: 1191– and hepcidin transcription. J Biol Chem 289: 23796– 1205. 23808. ZhouJ,Lee PL, Lee CI, WeiSY,LimSH, Lin TE, Chien S, Chiu Zuo W,Huang F,Chiang YJ, Li M, Du J, Ding Y,Zhang T,Lee JJ. 2013. BMP receptor-integrin interaction mediates re- HW, Jeong LS, Chen YL, et al. 2013. c-Cbl-Mediated sponses of vascular endothelial Smad1/5 and prolifera- neddylation antagonizes ubiquitination and degradation tion to disturbed flow. J Thromb Haemost 11: 741–755. of the TGF-b type II receptor. Mol Cell 49: 499–510.

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Signaling Receptors for TGF-β Family Members

Carl-Henrik Heldin and Aristidis Moustakas

Cold Spring Harb Perspect Biol 2016; doi: 10.1101/cshperspect.a022053

Subject Collection The Biology of the TGF-β Family

TGF-β Family Signaling in Early Vertebrate TGF-β Family Signaling in Mesenchymal Development Differentiation Joseph Zinski, Benjamin Tajer and Mary C. Mullins Ingo Grafe, Stefanie Alexander, Jonathan R. Peterson, et al. Bone Morphogenetic Protein−Based Therapeutic TGF-β1 Signaling and Tissue Fibrosis Approaches Kevin K. Kim, Dean Sheppard and Harold A. Jonathan W. Lowery and Vicki Rosen Chapman TGF-β Family Signaling in Ductal Differentiation Bone Morphogenetic Proteins in Vascular and Branching Morphogenesis Homeostasis and Disease Kaoru Kahata, Varun Maturi and Aristidis Marie-José Goumans, An Zwijsen, Peter ten Dijke, Moustakas et al. TGF-β Signaling in Control of Cardiovascular TGF-β Family Signaling in Epithelial Function Differentiation and Epithelial−Mesenchymal Marie-José Goumans and Peter ten Dijke Transition Kaoru Kahata, Mahsa Shahidi Dadras and Aristidis Moustakas TGF-β Family Signaling in Tumor Suppression TGF-β Family Signaling in Connective Tissue and and Cancer Progression Skeletal Diseases Joan Seoane and Roger R. Gomis Elena Gallo MacFarlane, Julia Haupt, Harry C. Dietz, et al. Targeting TGF-β Signaling for Therapeutic Gain The TGF-β Family in the Reproductive Tract Rosemary J. Akhurst Diana Monsivais, Martin M. Matzuk and Stephanie A. Pangas Regulation of Hematopoiesis and Hematological TGF-β Family Signaling in Drosophila Disease by TGF- β Family Signaling Molecules Ambuj Upadhyay, Lindsay Moss-Taylor, Myung-Jun Kazuhito Naka and Atsushi Hirao Kim, et al. TGF-β Family Signaling in Neural and Neuronal Signaling Cross Talk between TGF-β/Smad and Differentiation, Development, and Function Other Signaling Pathways Emily A. Meyers and John A. Kessler Kunxin Luo For additional articles in this collection, see http://cshperspectives.cshlp.org/cgi/collection/

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