DOCSLIB.ORG

The Ras-Related Gtpase Rac1 Regulates a Proliferative Pathway Selectively Utilized by G-Protein Coupled Receptors

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Ras-Related Gtpase Rac1 Regulates a Proliferative Pathway Selectively Utilized by G-Protein Coupled Receptors Oncogene (1998) 17, 1617 ± 1623 1998 Stockton Press All rights reserved 0950 ± 9232/98 $12.00 http://www.stockton-press.co.uk/onc The ras-related GTPase rac1 regulates a proliferative pathway selectively utilized by G-protein coupled receptors Ethan S Burstein1, Diane J Hesterberg1, J Silvio Gutkind2, Mark R Brann1, Erika A Currier1 and Terri L Messier1 1ACADIA Pharmaceuticals Inc., 3911 Sorrento Valley Blvd., San Diego, California 92121; 2Molecular Signaling Unit, Oral and Pharyngeal Cancer Branch, National Institute of Dental Research, National Institutes of Health, 9000 Rockville Pike, Bethesda, Maryland 20892-4330, USA Ras and rac are each members of the superfamily of GTPases can be constitutively activated by mutations monomeric GTPases and both function as molecular which impair GTPase activity (Bourne et al., 1991; switches to link cell-surface signals to intracellular Lowy and Willumsen, 1993; Barbacid, 1987), while responses. Using a novel assay of cellular proliferation dominant negative alleles can be created by mutations called R-SATTM (Receptor Selection and Ampli®cation that render these proteins unable to bind GTP (Feig Technology), we examined the roles of ras and rac in and Cooper, 1988). The ras proteins regulate a wide mediating the proliferative responses to a variety of cell- variety of cellular processes including growth and surface receptors. Activated, wild-type and dominant- dierentiation, and constitutively activated ras is negative mutants of rac and ras were tested for their oncogenic. The rac proteins control cytoskeletal eects on cellular proliferation either alone or in assembly (Tapon and Hall, 1997) and the exchange combination with receptors. Activated rac (rac Q61L, factors that activate rac are also oncogenic (Hart et al., henceforth rac*) and ras (ras G12V, henceforth ras*) 1994; Horii et al., 1994; Cerione and Zheng 1996) each induced strong proliferative responses. Dominant- implying that like ras, rac also regulates mitogenic negative rac (rac T17N, henceforth rac(7)) dramatically signaling pathways. suppressed proliferative responses to G-protein coupled Three distinct protein phosphorylation cascades receptors (GPCR's) including the m5 muscarinic have been described which mediate intracellular receptor and the a1B adrenergic receptor. In contrast, responses to extracellular signals (Denhardt, 1996), rac(7) had little or no eect upon responses to the including the MAP/ERK kinase cascade (Marshall, tyrosine kinase receptor TrkC, and only partially 1995; Davis, 1993) which is preferentially activated by suppressed responses to the Janus kinase (JAK/STAT) mitogens and growth factors and the SAPK/JNK and/ linked granulocyte macrophage colony stimulating factor or p38 kinase cascades which are preferentially (GM-CSF) receptor. Dominant-negative ras (ras T17N, activated by cytokines and cellular stress (Kyriakis et henceforth ras(7)) blocked the proliferative responses to al., 1994; Derijard et al., 1994). The MAP/ERK kinase all of the tested receptors. Compared to rac(7) and cascade is linked to inputs from cell surface receptors ras(7), wild-type rac and ras had only modest eects on by ras while rac and rac-related GTPases activate the the tested receptors. Overall these results demonstrate SAPK/JNK pathway (Coso et al., 1995; Minden et al., that rac mediates the proliferative eects of G-protein 1995). coupled receptors through a pathway that is distinct from The molecular links between cell surface receptors the proliferative signaling pathway utilized by tyrosine and intracellular kinase cascades is the subject of kinase linked and JAK-linked receptors. intensive research. The pathways utilized by growth factor receptors which have tyrosine kinase activity are Keywords: rac; ras; G-protein coupled receptor; currently the best understood (Schlessinger, 1993). tyrosine kinase linked receptor; JAK/STAT linked Upon ligand binding, the tyrosine kinase linked receptor receptors dimerize, become autophosphorylated, and recruit signaling molecules including adaptor proteins such as Grb2 and Shc. This receptor/adaptor complex can then bind ras exchange factors which catalyze the Introduction exchange of GTP for GDP, leading to activation of ras which in turn activates a variety of cellular eectors Rac and ras are each members of the superfamily of including the MAP/ERK kinase cascade. monomeric GTPases (Hall, 1990; 1994). These Cytokine receptors signal using a similar strategy GTPases function as molecular switches which are (Ihle, 1995). Ligand binding causes receptor aggrega- activated upon binding GTP, and become deactivated tion which promotes association of the receptors with by hydrolyzing GTP to GDP. The monomeric intracellular tyrosine kinases called JAKs (Janus kinases). The JAKs can then directly activate a family of transcription factors called STATs (Signal Transdu- cers and Activators of Transcription). Thus, these receptors are also known as JAK/STAT linked Correspondence: ES Burstein receptors. The JAK/STAT receptors induce tyrosine Received 8 December 1997; revised 20 April 1998; accepted 21 April phosphorylation of vav which has high homology to 1998 exchange factors that activate rac-related GTPases. Rac-regulated proliferative pathways ES Burstein et al 1618 The JAK/STAT linked receptors also recruit many of proliferation (Denhardt, 1996). The monomeric the same signaling molecules the tyrosine kinase GTPase ras plays a pivotal role in linking cell surface receptors utilize, and have been shown to activate ras. receptors to intracellular signaling pathways and Compared to the tyrosine-kinase and JAK/STAT recently it has become clear that the ras-related linked receptors, less is known about the signaling GTPase rac performs similar functions. We therefore pathways linking GPCR's to proliferative responses. tested activated, wild-type and dominant negative GPCR's have been shown to stimulate the phosphor- mutants of rac and ras for their eects on cellular ylation of both MAPK's and JNK's (Gardener et al., proliferation either alone or in combination with 1993; Coso et al., 1995b), however it is not apparent receptors. As shown in Figure 1, both rac and which pathways are required by GPCR's to generate constitutively activated rac (rac*, see Materials and mitogenic signals, nor is it clear how they are linked to methods) induced signi®cant proliferative responses, kinase cascades. We have developed a high throughput amplifying cells up to threefold over control values. functional assay called R-SAT (Receptor Selection and The response was dose-dependent, and was greater for Ampli®cation Technology, see Burstein et al., 1995) rac* than rac. For comparison, wild-type and activated which measures proliferative responses of cultured versions of the heterotrimeric G-protein Ga13, which is cells. Using R-SAT, we have found that compared to oncogenic (Dhanasekaran and Dermott, 1996; Voyno- other cell surface receptors, G-protein coupled Yasenetskaya et al., 1994) and is thought to regulate receptors are selectively linked by rac to proliferative rac-dependent signaling pathways (Voyno-Yasenets- signaling pathways. kaya et al., 1996; Vara Prasad et al., 1995), were also tested. Ga13* induced a response very similar in magnitude to rac*. As expected ras* induced very Results strong proliferative responses. We next tested the eects of co-expressing wild-type G-protein coupled receptors (GPCR's), tyrosine and dominant negative versions of rac and ras upon kinase-linked receptors and JAK/STAT-linked recep- the cellular responses induced by m5 muscarinic tors each activate intracellular kinase cascades, which receptor. As shown in Figure 2, NIH3T3 cells in turn mediate complex cellular responses such as transfected with the m5 muscarinic receptor (Bonner Figure 1 Stimulation of proliferative responses by G-proteins. NIH3T3 cells were transfected with the indicated amounts of G- Figure 2 Eects of ras and rac on proliferative responses to the protein, 500 ng of b-galactosidase and sucient control vector to m5 muscarinic receptor. NIH3T3 cells were transfected with 40 bring the total pool to 1 mg DNA. Transfected cells were cultured nanograms of receptor. 500 ng of b-galactosidase, 800 ng of G- and assayed by R-SATTM as described in the Materials and protein and sucient control vector to bring the total pool to methods. Rac*, ras* and Ga13* are constitutively activated by 1.5 mg DNA. Transfected cells were cultured with the indicated mutations (to rac Q61L, ras G12V and Ga13 Q226L respectively) concentrations of carbachol and assayed by R-SATTM as which impair their intrinsic GTPase activities (see Bourne et al., described in Materials and methods. Rac(7) and ras(7) are 1991). Fold stimulation was calculated as the ratio of G-protein each dominant negative mutants which contain the mutation response to control response. Control transfections consisted of b- T17N, rendering these proteins unable to bind GTP (see Feig and gal and control vector Cooper, 1988) Rac-regulated proliferative pathways ES Burstein et al 1619 Figure 3 Eects of ras and rac on proliferative responses to receptors. NIH3T3 cells were transfected with 40 nanograms of receptor, 500 ng of b-galactosidase, 800 ng of G-protein and sucient control vector to bring the total pool to 1.5 mg DNA. Transfected cells were cultured in the presence of the indicated concentrations of ligand and assayed by R-SATTM as described in the Materials and methods. Open circles, receptor; open squares, receptor + rac; ®lled squares, receptor
Load more

Recommended publications
  • The Rac Gtpase in Cancer: from Old Concepts to New Paradigms Marcelo G
    Published OnlineFirst August 14, 2017; DOI: 10.1158/0008-5472.CAN-17-1456 Cancer Review Research The Rac GTPase in Cancer: From Old Concepts to New Paradigms Marcelo G. Kazanietz1 and Maria J. Caloca2 Abstract Rho family GTPases are critical regulators of cellular func- mislocalization of Rac signaling components. The unexpected tions that play important roles in cancer progression. Aberrant pro-oncogenic functions of Rac GTPase-activating proteins also activity of Rho small G-proteins, particularly Rac1 and their challenged the dogma that these negative Rac regulators solely regulators, is a hallmark of cancer and contributes to the act as tumor suppressors. The potential contribution of Rac tumorigenic and metastatic phenotypes of cancer cells. This hyperactivation to resistance to anticancer agents, including review examines the multiple mechanisms leading to Rac1 targeted therapies, as well as to the suppression of antitumor hyperactivation, particularly focusing on emerging paradigms immune response, highlights the critical need to develop ther- that involve gain-of-function mutations in Rac and guanine apeutic strategies to target the Rac pathway in a clinical setting. nucleotide exchange factors, defects in Rac1 degradation, and Cancer Res; 77(20); 5445–51. Ó2017 AACR. Introduction directed toward targeting Rho-regulated pathways for battling cancer. Exactly 25 years ago, two seminal papers by Alan Hall and Nearly all Rho GTPases act as molecular switches that cycle colleagues illuminated us with one of the most influential dis- between GDP-bound (inactive) and GTP-bound (active) forms. coveries in cancer signaling: the association of Ras-related small Activation is promoted by guanine nucleotide exchange factors GTPases of the Rho family with actin cytoskeleton reorganization (GEF) responsible for GDP dissociation, a process that normally (1, 2).
    [Show full text]
  • 1 Metabolic Dysfunction Is Restricted to the Sciatic Nerve in Experimental
    Page 1 of 255 Diabetes Metabolic dysfunction is restricted to the sciatic nerve in experimental diabetic neuropathy Oliver J. Freeman1,2, Richard D. Unwin2,3, Andrew W. Dowsey2,3, Paul Begley2,3, Sumia Ali1, Katherine A. Hollywood2,3, Nitin Rustogi2,3, Rasmus S. Petersen1, Warwick B. Dunn2,3†, Garth J.S. Cooper2,3,4,5* & Natalie J. Gardiner1* 1 Faculty of Life Sciences, University of Manchester, UK 2 Centre for Advanced Discovery and Experimental Therapeutics (CADET), Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK 3 Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, UK 4 School of Biological Sciences, University of Auckland, New Zealand 5 Department of Pharmacology, Medical Sciences Division, University of Oxford, UK † Present address: School of Biosciences, University of Birmingham, UK *Joint corresponding authors: Natalie J. Gardiner and Garth J.S. Cooper Email: [email protected]; [email protected] Address: University of Manchester, AV Hill Building, Oxford Road, Manchester, M13 9PT, United Kingdom Telephone: +44 161 275 5768; +44 161 701 0240 Word count: 4,490 Number of tables: 1, Number of figures: 6 Running title: Metabolic dysfunction in diabetic neuropathy 1 Diabetes Publish Ahead of Print, published online October 15, 2015 Diabetes Page 2 of 255 Abstract High glucose levels in the peripheral nervous system (PNS) have been implicated in the pathogenesis of diabetic neuropathy (DN). However our understanding of the molecular mechanisms which cause the marked distal pathology is incomplete. Here we performed a comprehensive, system-wide analysis of the PNS of a rodent model of DN.
    [Show full text]
  • P2Y Purinergic Receptors, Endothelial Dysfunction, and Cardiovascular Diseases
    International Journal of Molecular Sciences Review P2Y Purinergic Receptors, Endothelial Dysfunction, and Cardiovascular Diseases Derek Strassheim 1, Alexander Verin 2, Robert Batori 2 , Hala Nijmeh 3, Nana Burns 1, Anita Kovacs-Kasa 2, Nagavedi S. Umapathy 4, Janavi Kotamarthi 5, Yash S. Gokhale 5, Vijaya Karoor 1, Kurt R. Stenmark 1,3 and Evgenia Gerasimovskaya 1,3,* 1 The Department of Medicine Cardiovascular and Pulmonary Research Laboratory, University of Colorado Denver, Aurora, CO 80045, USA; [email protected] (D.S.); [email protected] (N.B.); [email protected] (V.K.); [email protected] (K.R.S.) 2 Vascular Biology Center, Augusta University, Augusta, GA 30912, USA; [email protected] (A.V.); [email protected] (R.B.); [email protected] (A.K.-K.) 3 The Department of Pediatrics, Division of Critical Care Medicine, University of Colorado Denver, Aurora, CO 80045, USA; [email protected] 4 Center for Blood Disorders, Augusta University, Augusta, GA 30912, USA; [email protected] 5 The Department of BioMedical Engineering, University of Wisconsin, Madison, WI 53706, USA; [email protected] (J.K.); [email protected] (Y.S.G.) * Correspondence: [email protected]; Tel.: +1-303-724-5614 Received: 25 August 2020; Accepted: 15 September 2020; Published: 18 September 2020 Abstract: Purinergic G-protein-coupled receptors are ancient and the most abundant group of G-protein-coupled receptors (GPCRs). The wide distribution of purinergic receptors in the cardiovascular system, together with the expression of multiple receptor subtypes in endothelial cells (ECs) and other vascular cells demonstrates the physiological importance of the purinergic signaling system in the regulation of the cardiovascular system.
    [Show full text]
  • ERK Interaction Induces Proliferative Activities of Cementifying Fibroma
    Laboratory Investigation (2011) 91, 379–391 & 2011 USCAP, Inc All rights reserved 0023-6837/11 $32.00 RHAMM/ERK interaction induces proliferative activities of cementifying fibroma cells through a mechanism based on the CD44–EGFR Hiroko Hatano1, Hideo Shigeishi1, Yasusei Kudo2, Koichiro Higashikawa1, Kei Tobiume1, Takashi Takata2 and Nobuyuki Kamata1 We have previously established immortalized cells (HCF) from cementifying fibroma of the jaw bone. Here, we found that the receptor for hyaluronan (HA)-mediated motility (RHAMM) and epiregulin, a ligand for the epidermal growth factor receptor (EGFR), were highly expressed in HCF cells in comparison with osteoblasts by conducting a microarray analysis. The cell growth of HCF cells was significantly decreased by the knockdown of RHAMM using small interfering RNA (siRNA). RHAMM was associated with extracellular signal-regulated kinase (ERK) and essential for ERK phosphorylation. HCF cells had characteristic growth mechanisms in which epiregulin functions in an extracellular autocrine loop. Inter- estingly, exogenous HA induced the phosphorylation of EGFR, which was mainly dependent on CD44. The results raise the novel idea that the EGFR may activate Raf–MEK–ERK signaling in response to the binding of HA to CD44. Moreover, RHAMM was able to associate with TPX2 in the nucleus and was required for HA-induced activation of the Aurora A kinase. The results suggest that RHAMM has a predominant role in the cell cycle in HCF. Here, we report the new machinery by which RHAMM/ERK interaction induces
    [Show full text]
  • Human Induced Pluripotent Stem Cell–Derived Podocytes Mature Into Vascularized Glomeruli Upon Experimental Transplantation
    BASIC RESEARCH www.jasn.org Human Induced Pluripotent Stem Cell–Derived Podocytes Mature into Vascularized Glomeruli upon Experimental Transplantation † Sazia Sharmin,* Atsuhiro Taguchi,* Yusuke Kaku,* Yasuhiro Yoshimura,* Tomoko Ohmori,* ‡ † ‡ Tetsushi Sakuma, Masashi Mukoyama, Takashi Yamamoto, Hidetake Kurihara,§ and | Ryuichi Nishinakamura* *Department of Kidney Development, Institute of Molecular Embryology and Genetics, and †Department of Nephrology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan; ‡Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Hiroshima, Japan; §Division of Anatomy, Juntendo University School of Medicine, Tokyo, Japan; and |Japan Science and Technology Agency, CREST, Kumamoto, Japan ABSTRACT Glomerular podocytes express proteins, such as nephrin, that constitute the slit diaphragm, thereby contributing to the filtration process in the kidney. Glomerular development has been analyzed mainly in mice, whereas analysis of human kidney development has been minimal because of limited access to embryonic kidneys. We previously reported the induction of three-dimensional primordial glomeruli from human induced pluripotent stem (iPS) cells. Here, using transcription activator–like effector nuclease-mediated homologous recombination, we generated human iPS cell lines that express green fluorescent protein (GFP) in the NPHS1 locus, which encodes nephrin, and we show that GFP expression facilitated accurate visualization of nephrin-positive podocyte formation in
    [Show full text]
  • Supplementary Information
    Supplementary information (a) (b) Figure S1. Resistant (a) and sensitive (b) gene scores plotted against subsystems involved in cell regulation. The small circles represent the individual hits and the large circles represent the mean of each subsystem. Each individual score signifies the mean of 12 trials – three biological and four technical. The p-value was calculated as a two-tailed t-test and significance was determined using the Benjamini-Hochberg procedure; false discovery rate was selected to be 0.1. Plots constructed using Pathway Tools, Omics Dashboard. Figure S2. Connectivity map displaying the predicted functional associations between the silver-resistant gene hits; disconnected gene hits not shown. The thicknesses of the lines indicate the degree of confidence prediction for the given interaction, based on fusion, co-occurrence, experimental and co-expression data. Figure produced using STRING (version 10.5) and a medium confidence score (approximate probability) of 0.4. Figure S3. Connectivity map displaying the predicted functional associations between the silver-sensitive gene hits; disconnected gene hits not shown. The thicknesses of the lines indicate the degree of confidence prediction for the given interaction, based on fusion, co-occurrence, experimental and co-expression data. Figure produced using STRING (version 10.5) and a medium confidence score (approximate probability) of 0.4. Figure S4. Metabolic overview of the pathways in Escherichia coli. The pathways involved in silver-resistance are coloured according to respective normalized score. Each individual score represents the mean of 12 trials – three biological and four technical. Amino acid – upward pointing triangle, carbohydrate – square, proteins – diamond, purines – vertical ellipse, cofactor – downward pointing triangle, tRNA – tee, and other – circle.
    [Show full text]
  • Minichromosome Maintenance Helicase Activity Is Controlled by N- and C-Terminal Motifs and Requires the Atpase Domain Helix-2 Insert
    Minichromosome maintenance helicase activity is controlled by N- and C-terminal motifs and requires the ATPase domain helix-2 insert Elizabeth R. Jenkinson and James P. J. Chong* Department of Biology, University of York, P.O. Box 373, York YO10 5YW, United Kingdom Edited by Bruce W. Stillman, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, and approved March 23, 2006 (received for review October 25, 2005) The minichromosome maintenance (MCM) proteins are essential improved by posttranslational modifications (e.g., ref. 16) or the conserved proteins required for DNA replication in archaea and presence of additional processivity factors. eukaryotes. MCM proteins are believed to provide the replicative The complexity of the eukaryotic MCM system means that helicase activity that unwinds template DNA ahead of the replica- addressing the molecular mechanisms required for unwinding has tion fork. Consistent with this hypothesis, MCM proteins can form been difficult. The archaea also possess MCM proteins but in a hexameric complexes that possess ATP-dependent DNA unwinding simplified form. Almost all archaeal species possess a single MCM activity. The molecular mechanism by which the energy of ATP that forms homohexameric complexes. Archaeal MCMs are useful hydrolysis is harnessed to DNA unwinding is unknown, although models for understanding some of the molecular mechanisms the ATPase activity has been attributed to a highly conserved underlying the eukaryotic heterohexameric MCM complex (17). -AAA؉ family ATPase domain. Here we show that changes to N- Biochemical studies of the Methanothermobacter thermautotrophi and C-terminal motifs in the single MCM protein from the archaeon cus MCM (MthMCM) demonstrated that this protein forms Methanothermobacter thermautotrophicus (MthMCM) can modu- double-hexamer complexes that bind ssDNA and dsDNA.
    [Show full text]
  • Novel Targets of Apparently Idiopathic Male Infertility
    International Journal of Molecular Sciences Review Molecular Biology of Spermatogenesis: Novel Targets of Apparently Idiopathic Male Infertility Rossella Cannarella * , Rosita A. Condorelli , Laura M. Mongioì, Sandro La Vignera * and Aldo E. Calogero Department of Clinical and Experimental Medicine, University of Catania, 95123 Catania, Italy; [email protected] (R.A.C.); [email protected] (L.M.M.); [email protected] (A.E.C.) * Correspondence: [email protected] (R.C.); [email protected] (S.L.V.) Received: 8 February 2020; Accepted: 2 March 2020; Published: 3 March 2020 Abstract: Male infertility affects half of infertile couples and, currently, a relevant percentage of cases of male infertility is considered as idiopathic. Although the male contribution to human fertilization has traditionally been restricted to sperm DNA, current evidence suggest that a relevant number of sperm transcripts and proteins are involved in acrosome reactions, sperm-oocyte fusion and, once released into the oocyte, embryo growth and development. The aim of this review is to provide updated and comprehensive insight into the molecular biology of spermatogenesis, including evidence on spermatogenetic failure and underlining the role of the sperm-carried molecular factors involved in oocyte fertilization and embryo growth. This represents the first step in the identification of new possible diagnostic and, possibly, therapeutic markers in the field of apparently idiopathic male infertility. Keywords: spermatogenetic failure; embryo growth; male infertility; spermatogenesis; recurrent pregnancy loss; sperm proteome; DNA fragmentation; sperm transcriptome 1. Introduction Infertility is a widespread condition in industrialized countries, affecting up to 15% of couples of childbearing age [1]. It is defined as the inability to achieve conception after 1–2 years of unprotected sexual intercourse [2].
    [Show full text]
  • Small Gtpases of the Ras and Rho Families Switch On/Off Signaling
    International Journal of Molecular Sciences Review Small GTPases of the Ras and Rho Families Switch on/off Signaling Pathways in Neurodegenerative Diseases Alazne Arrazola Sastre 1,2, Miriam Luque Montoro 1, Patricia Gálvez-Martín 3,4 , Hadriano M Lacerda 5, Alejandro Lucia 6,7, Francisco Llavero 1,6,* and José Luis Zugaza 1,2,8,* 1 Achucarro Basque Center for Neuroscience, Science Park of the Universidad del País Vasco/Euskal Herriko Unibertsitatea (UPV/EHU), 48940 Leioa, Spain; [email protected] (A.A.S.); [email protected] (M.L.M.) 2 Department of Genetics, Physical Anthropology, and Animal Physiology, Faculty of Science and Technology, UPV/EHU, 48940 Leioa, Spain 3 Department of Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Granada, 180041 Granada, Spain; [email protected] 4 R&D Human Health, Bioibérica S.A.U., 08950 Barcelona, Spain 5 Three R Labs, Science Park of the UPV/EHU, 48940 Leioa, Spain; [email protected] 6 Faculty of Sport Science, European University of Madrid, 28670 Madrid, Spain; [email protected] 7 Research Institute of the Hospital 12 de Octubre (i+12), 28041 Madrid, Spain 8 IKERBASQUE, Basque Foundation for Science, 48013 Bilbao, Spain * Correspondence: [email protected] (F.L.); [email protected] (J.L.Z.) Received: 25 July 2020; Accepted: 29 August 2020; Published: 31 August 2020 Abstract: Small guanosine triphosphatases (GTPases) of the Ras superfamily are key regulators of many key cellular events such as proliferation, differentiation, cell cycle regulation, migration, or apoptosis. To control these biological responses, GTPases activity is regulated by guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs), and in some small GTPases also guanine nucleotide dissociation inhibitors (GDIs).
    [Show full text]
  • G Protein Coupled Receptor Signaling Through the Src and Stat3 Pathway: Role in Proliferation and Transformation
    Oncogene (2001) 20, 1601 ± 1606 ã 2001 Nature Publishing Group All rights reserved 0950 ± 9232/01 $15.00 www.nature.com/onc G protein coupled receptor signaling through the Src and Stat3 pathway: role in proliferation and transformation Prahlad T Ram*,1 and Ravi Iyengar1 1Department of Pharmacology, Mount Sinai School of Medicine, New York, NY 10029, USA Extracellular signals when routed through signaling transducin; the Gai family which includes Gai, Gao pathways that use heterotrimeric G proteins can and Gaz; the Gaq/Ga11 family; and the Ga12/13 engage multiple signaling pathways leading to diverse family. As these new Ga subunits were identi®ed the biological consequences. One locus at which signal eectors pathways for these subunits were sought out, sorting occurs is at the level of G proteins. G protein and over the years a number of eector pathways such a-subunits appear to be capable of interacting with as the PLC, Rho/Cdc42 pathways, and the Ca2+ dierent eectors leading to engagement of distinct channels have been identi®ed (Buhl et al., 1995; signaling pathways. Regulation of dierent pathways Diverse-Pierluissi, 1995; rench-Mullen et al., 1994; in turn leads to dierent biological outcomes. The Taylor et al., 1990). In addition to activation of process of neoplastic transformation is controlled to a second messenger molecules, Ga subunits can also large extent through the activation and inhibition of modulate the activity of transcription factors, thereby signaling pathways. Signaling pathways such as the regulating gene expression (Corre et al., 1999; Fan et Ras-MAPK, v-Src-Stat3 pathways are activated in the al., 2000; Montminy, 1997; Ram et al., 2000).
    [Show full text]
  • Cdk5 Regulation of the GRAB-Mediated Rab8-Rab11 Cascade in Axon Outgrowth
    790 • The Journal of Neuroscience, January 25, 2017 • 37(4):790–806 Cellular/Molecular Cdk5 Regulation of the GRAB-Mediated Rab8-Rab11 Cascade in Axon Outgrowth Kotaro Furusawa,1 Akiko Asada,1 Pamela Urrutia,2,3 Christian Gonzalez-Billault,2,3,4 XMitsunori Fukuda,5 and X Shin-ichi Hisanaga1 1Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, Minami-Osawa, Hachioji, Tokyo 192-0397, Japan, 2Department of Biology, Faculty of Sciences, Universidad de Chile, 7800024 Nunoa, Chile, 3FONDAP Geroscience Center for Brain Health and Metabolism, 7500922 Santiago, Chile, 4Buck Institute for Research on Aging, Novato, California 94945, and 5Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aoba-ku, Sendai, Miyagi 980-8578, Japan Neurons communicate with each other through their axons and dendrites. However, a full characterization of the molecular mechanisms involved in axon and dendrite formation is still incomplete. Neurite outgrowth requires the supply of membrane components for surface expansion. Two membrane sources for axon outgrowth are suggested: Golgi secretary vesicles and endocytic recycling endosomes. In non-neuronal cells, trafficking of secretary vesicles from Golgi is regulated by Rab8, a member of Rab small GTPases, and that of recycling endosomes is by Rab11, another member of Rabs. However, whether these vesicles are coordinately or independently transported in growing axons is unknown. Herein, we find that GRAB, a guanine nucleotide exchange factor for Rab8, is a novel regulator of axon outgrowth. Knockdown of GRAB suppressed axon outgrowth of cultured mouse brain cortical neurons. GRAB mediates the interaction between Rab11A and Rab8A, and this activity is regulated by phosphorylation at Ser169 and Ser180 by Cdk5-p35.
    [Show full text]
  • Regulation, Activation and Function of Caspase-11 During Health and Disease
    International Journal of Molecular Sciences Review Regulation, Activation and Function of Caspase-11 during Health and Disease Aidan Agnew †, Ciara Nulty † and Emma M. Creagh * School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, D02R590 Dublin, Ireland; [email protected] (A.A.); [email protected] (C.N.) * Correspondence: [email protected] † These authors contributed equally to this work. Abstract: Caspase-11 is a pro-inflammatory enzyme that is stringently regulated during its expression and activation. As caspase-11 is not constitutively expressed in cells, it requires a priming step for its upregulation, which occurs following the stimulation of pathogen and cytokine receptors. Once expressed, caspase-11 activation is triggered by its interaction with lipopolysaccharide (LPS) from Gram-negative bacteria. Being an initiator caspase, activated caspase-11 functions primarily through its cleavage of key substrates. Gasdermin D (GSDMD) is the primary substrate of caspase-11, and the GSDMD cleavage fragment generated is responsible for the inflammatory form of cell death, pyroptosis, via its formation of pores in the plasma membrane. Thus, caspase-11 functions as an intracellular sensor for LPS and an immune effector. This review provides an overview of caspase-11— describing its structure and the transcriptional mechanisms that govern its expression, in addition to its activation, which is reported to be regulated by factors such as guanylate-binding proteins (GBPs), high mobility group box 1 (HMGB1) protein, and oxidized phospholipids. We also discuss the functional outcomes of caspase-11 activation, which include the non-canonical inflammasome, modulation of actin dynamics, and the initiation of blood coagulation, highlighting the importance Citation: Agnew, A.; Nulty, C.; of inflammatory caspase-11 during infection and disease.
    [Show full text]