DOCSLIB.ORG

Phox Homology Band 4.1/Ezrin/Radixin/Moesin-Like Proteins Function As Molecular Scaffolds That Interact with Cargo Receptors and Ras Gtpases

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Phox Homology Band 4.1/Ezrin/Radixin/Moesin-Like Proteins Function As Molecular Scaffolds That Interact with Cargo Receptors and Ras Gtpases Phox homology band 4.1/ezrin/radixin/moesin-like proteins function as molecular scaffolds that interact with cargo receptors and Ras GTPases Rajesh Ghai, Mehdi Mobli, Suzanne J. Norwood, Andrea Bugarcic, Rohan D. Teasdale, Glenn F. King, and Brett M. Collins1 Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia Edited by Frances M. Brodsky, University of California, San Francisco, CA, and accepted by the Editorial Board March 15, 2011 (received for review November 29, 2010) Following endocytosis, the fates of receptors, channels, and other the disease. The homology of SNX31 to SNX17 (approximately transmembrane proteins are decided via specific endosomal sort- 40% identity) suggests an involvement in similar endosomal ing pathways, including recycling to the cell surface for continued transport pathways. activity. Two distinct phox-homology (PX)-domain-containing pro- SNX27 is unique among the PX proteins, containing an teins, sorting nexin (SNX) 17 and SNX27, are critical regulators of N-terminal PDZ domain upstream of the PX domain. SNX27 recycling from endosomes to the cell surface. In this study we de- has also been annotated to possess a Ras-association domain monstrate that SNX17, SNX27, and SNX31 all possess a novel 4.1/ and extended C-terminal region (1, 2, 13). SNX27 was first iden- ezrin/radixin/moesin (FERM)-like domain. SNX17 has been shown tified as a binding partner for the 5-hydroxytryptamine type-4 to bind to Asn-Pro-Xaa-Tyr (NPxY) sequences in the cytoplasmic receptor (5-HT4R) (13), and overexpression of SNX27 directs tails of cargo such as LDL receptors and the amyloid precursor pro- localization of 5-HT4R and Kir3 potassium channels to early tein, and we find that both SNX17 and SNX27 display similar affi- endosomal autoantigen 1 (EEA1)-positive early endosomes nities for NPxY sorting motifs, suggesting conserved functions in (13, 14). There is accumulating evidence for a role for SNX27 endosomal recycling. Furthermore, we show for the first time that in coupling protein sorting to cell signaling. It can direct the BIOCHEMISTRY all three proteins are able to bind the Ras GTPase through their endosome-to-cell surface recycling of the β2 adrenergic receptor FERM-like domains. These interactions place the PX-FERM-like (15), and SNX27 may also scaffold signaling and lipid modulating proteins at a hub of endosomal sorting and signaling processes. complexes by interacting with proteins such as diacylglycerolki- Studies of the SNX17 PX domain coupled with cellular localization nase ζ (16), NMDA receptors (17), and cytohesin associated experiments reveal the mechanistic basis for endosomal localiza- scaffolding protein (CASP) (18). All of these molecules bind tion of the PX-FERM-like proteins, and structures of SNX17 and to SNX27 via type-I PDZ-domain binding motifs. SNX27 determined by small angle X-ray scattering show that they Recent studies suggest that some PX proteins may play dual adopt non-self-assembling, modular structures in solution. In roles in membrane trafficking and cell signaling (19, 20), and summary, this work defines a novel family of proteins that parti- there is mounting evidence that endosomal sorting of receptors cipate in a network of interactions that will impact on both endo- is a key factor in determining differential signaling outcomes somal protein trafficking and compartment specific Ras signaling (21, 22). For example, signaling by the Ras oncogene has for cascades. many years been thought to occur primarily at the plasma mem- brane. More recent assessments of the spatiotemporal control of hox-homology (PX) domain-containing proteins are a diverse Ras signaling have demonstrated the existence of Ras-mediated Pfamily of proteins implicated in many protein trafficking pro- signaling events on intracellular membranes including Ras/ cesses, and there is emerging recognition of their importance in MAPK signaling on endosomes (23, 24). cell signaling (1, 2). The PX domain binds phosphatidylinositol Here we show that SNX17, SNX27, and SNX31 define a un- phospholipids (PIPs) to mediate localization to subcellular mem- ique subfamily of PX proteins possessing an unusual band 4.1/ branous compartments for regulation of cargo transport and ezrin/radixin/moesin (FERM)-like structure, which incorporates processing. Most PX proteins also contain a variety of other func- the previously annotated Ras-association domain of SNX27. We tional modules including Ras-association (RA) and PSD-95/discs find that the members of this family share both NPxY peptide- large/zona occludens (PDZ) domains. Thus PX proteins can binding properties and an ability to associate with H-Ras in a function as scaffolds that facilitate spatiotemporal assembly of GTP-dependent manner. Structural studies of the PX-FERM- membrane trafficking and signaling complexes. like proteins reveal the molecular mechanisms for membrane The PX-protein sorting nexin 17 (SNX17) is important for endosomal sorting of transmembrane proteins from endosomes Author contributions: R.G., R.D.T., G.F.K., and B.M.C. designed research; R.G., M.M., S.J.N., to the cell surface. Identified cargo molecules include the low- A.B., and B.M.C. performed research; R.D.T. and G.F.K. contributed new reagents/analytic density lipoprotein receptor (LDLR), and other members of the tools; R.G., M.M., S.J.N., A.B., R.D.T., G.F.K., and B.M.C. analyzed data; and R.G., S.J.N., A.B., LDLR family including LDLR-related protein 1 (LRP1), suggest- and B.M.C. wrote the paper. ing an important role in lipid metabolism (3–5). SNX17 also The authors declare no conflict of interest. regulates the trafficking of P-selectin (6) and FEEL-1 (7) and as- This article is a PNAS Direct Submission. F.M.B. is a guest editor invited by the Editorial sociates with cytosolic factors Krit1 (8) and Kif1B (9). All of these Board. proteins have been found to bind SNX17 via a conserved Asn- Data deposition: Coordinates and structure factors for the SNX17 PX domain have been Pro-Xaa-Tyr (NPxY) sequence motif, but the molecular basis deposited in the RCSB Protein Data Bank, www.pdb.org/pdb/home/home.do (PDB ID of this interaction is unknown. Recent data indicate an important code 3LUI). Raw diffraction images are available on the Diffraction Image Experiment Repository (DIMER) at http://xr-diffraction.imb.uq.edu.au. NMR assignments have role for SNX17 in trafficking of the amyloid precursor protein been deposited in the Biological Magnetic Resonance Bank (http://www.bmrb.wisc.edu/) (APP) central to Alzheimer’s disease (AD) (10). As the LDLR (BMRB accession number 17497). family, in particular LRP1, have also been linked to AD and play 1To whom correspondence should be addressed. E-mail: [email protected]. direct roles in APP trafficking (11, 12), it appears SNX17 func- This article contains supporting information online at www.pnas.org/lookup/suppl/ tions at a nexus of endosomal trafficking pathways important for doi:10.1073/pnas.1017110108/-/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.1017110108 PNAS Early Edition ∣ 1of6 Downloaded by guest on October 1, 2021 recruitment and their overall domain architectures, highlighting a tein APP (Fig. 2A and Table S1). Significant binding was observed 32 Æ 5 μ structural scaffold primed for assembly of endosomal trafficking with a Kd of M. This low micromolar affinity is typical of and signaling complexes. Our work points to a role for PX- coat–cargo interactions in other systems such as clathrin-coated FERM-like proteins as interaction hubs that will have key func- vesicle formation. Titrations using a peptide in which the key tions in endosomal trafficking and Ras-mediated signaling and Tyr side chain was mutated to Ala showed no significant binding, provides a foundation for future studies of these processes. confirming the specificity of the interaction. Previous reports have indicated that the C terminus of SNX17 is required for Results NPxY binding (6, 8), but the mechanism underpinning this inter- Defining a Unique PX-FERM-Like Protein Family. FERM domains are action is unknown. As we have found that this region contains a found in numerous molecules where they regulate lipid and pro- FERM-like domain with a PTB-related F3 module, it is highly tein interactions. They are approximately 300 residues in length likely that this interaction occurs via binding to this structure, and contain three modules termed F1, F2, and F3 (25). F1 has a as observed in the complex formed between the FE65 PTB ubiquitin-related fold, F2 an α-helical structure, and F3 has struc- domain and APP (27). To investigate if other PX-FERM-like tural similarity to phosphotyrosine-binding (PTB) domains. Both proteins also interact with cargo receptors containing the NPxY SNX17 and SNX31 have been annotated to possess a C-terminal motif, SNX27 was titrated with the APP NPxY peptide (Fig. 2B). sequence similar to the N terminus of FERM domains (1, 2, 6, 8). SNX27 bound the APP peptide with similar affinity to SNX17 ¼ 27 6 Æ 0 1 μ We performed a secondary structure-based comparison of (Kd . M), and the SNX27 FERM-like domain binds SNX17 and SNX31 and found that the C-terminal region of both the APP peptide sequence with almost identical affinity to the ¼ 22 9 Æ 13 4 μ proteins, in fact, contains canonical F1 and F3 structures (Fig. 1). full-length protein (Kd . M). To date, SNX27 has However, unlike classical FERM domains, SNX17 and SNX31 been found to bind cargo only via its PDZ domain; hence we show possess an altered F2 module. Instead of four helices, the F2 that like SNX17, SNX27 is able to associate specifically with modules of SNX17 and SNX31 are predicted to have three and NPxY motif-containing cargo receptors.
Load more

Recommended publications
  • Sorting Nexins in Protein Homeostasis Sara E. Hanley1,And Katrina F
    Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 6 November 2020 doi:10.20944/preprints202011.0241.v1 Sorting nexins in protein homeostasis Sara E. Hanley1,and Katrina F. Cooper2* 1Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University, Stratford, NJ, 08084, USA 1 [email protected] 2 [email protected] * [email protected] Tel: +1 (856)-566-2887 1Department of Molecular Biology, Graduate School of Biomedical Sciences, Rowan University, Stratford, NJ, 08084, USA Abstract: Sorting nexins (SNXs) are a highly conserved membrane-associated protein family that plays a role in regulating protein homeostasis. This family of proteins is unified by their characteristic phox (PX) phosphoinositides binding domain. Along with binding to membranes, this family of SNXs also comprises a diverse array of protein-protein interaction motifs that are required for cellular sorting and protein trafficking. SNXs play a role in maintaining the integrity of the proteome which is essential for regulating multiple fundamental processes such as cell cycle progression, transcription, metabolism, and stress response. To tightly regulate these processes proteins must be expressed and degraded in the correct location and at the correct time. The cell employs several proteolysis mechanisms to ensure that proteins are selectively degraded at the appropriate spatiotemporal conditions. SNXs play a role in ubiquitin-mediated protein homeostasis at multiple levels including cargo localization, recycling, degradation, and function. In this review, we will discuss the role of SNXs in three different protein homeostasis systems: endocytosis lysosomal, the ubiquitin-proteasomal, and the autophagy-lysosomal system. The highly conserved nature of this protein family by beginning with the early research on SNXs and protein trafficking in yeast and lead into their important roles in mammalian systems.
    [Show full text]
  • Structural and Functional Insights Into Sorting Nexin 5/6 Interaction with Bacterial Effector Ince
    OPEN Citation: Signal Transduction and Targeted Therapy (2017) 2, e17030; doi:10.1038/sigtrans.2017.30 www.nature.com/sigtrans ARTICLE Structural and functional insights into sorting nexin 5/6 interaction with bacterial effector IncE Qingxiang Sun1,5, Xin Yong1,2,5, Xiaodong Sun3,5, Fan Yang1,2,5, Zhonghua Dai4, Yanqiu Gong1, Liming Zhou3, Xia Zhang1, Dawen Niu1, Lunzhi Dai1, Jia-Jia Liu4 and Da Jia1,2 The endosomal trafficking pathways are essential for many cellular activities. They are also important targets by many intracellular pathogens. Key regulators of the endosomal trafficking include the retromer complex and sorting nexins (SNXs). Chlamydia trachomatis effector protein IncE directly targets the retromer components SNX5 and SNX6 and suppresses retromer-mediated transport, but the exact mechanism has remained unclear. We present the crystal structure of the PX domain of SNX5 in complex with IncE, showing that IncE binds to a highly conserved hydrophobic groove of SNX5. The unique helical hairpin of SNX5/6 is essential for binding, explaining the specificity of SNX5/6 for IncE. The SNX5/6–IncE interaction is required for cellular localization of IncE and its inhibitory function. Mechanistically, IncE inhibits the association of CI-MPR cargo with retromer-containing endosomal subdomains. Our study provides new insights into the regulation of retromer-mediated transport and illustrates the intricate competition between host and pathogens in controlling cellular trafficking. Signal Transduction and Targeted Therapy (2017) 2, e17030; doi:10.1038/sigtrans.2017.30;
    [Show full text]
  • Activated Ezrin Controls MISP Levels to Ensure Correct Numa Polarization and Spindle Orientation Yvonne T
    © 2018. Published by The Company of Biologists Ltd | Journal of Cell Science (2018) 131, jcs214544. doi:10.1242/jcs.214544 RESEARCH ARTICLE Activated ezrin controls MISP levels to ensure correct NuMA polarization and spindle orientation Yvonne T. Kschonsak1,2 and Ingrid Hoffmann1,* ABSTRACT misregulation in spindle orientation can result in disorganized tissue Correct spindle orientation is achieved through signaling pathways that morphology due to cell multi-layering, which could be associated provide a molecular link between the cell cortex and spindle with the earliest cancer developments (McCaffrey and Macara, microtubules in an F-actin-dependent manner. A conserved cortical 2011; Pease and Tirnauer, 2011). protein complex, composed of LGN (also known as GPSM2), NuMA The precise spindle position and orientation in the cell is achieved (also known as NUMA1) and dynein–dynactin, plays a key role in by signaling pathways generating pulling and pushing forces on the establishing proper spindle orientation. It has also been shown that the spindle, both externally or internally (Gönczy, 2002; Grill and actin-binding protein MISP and the ERM family, which are activated by Hyman, 2005; Théry et al., 2005; Fink et al., 2011). The longest lymphocyte-oriented kinase (LOK, also known as STK10) and Ste20- established player in spindle orientation is the conserved ternary α like kinase (SLK) (hereafter, SLK/LOK) in mitosis, regulate spindle complex, composed of G i, Leu-Gly-Asn repeat-enriched protein orientation. Here, we report that MISP functions downstream of the (LGN, also known as GPSM2) and nuclear mitotic apparatus ERM family member ezrin and upstream of NuMA to allow optimal (NuMA, also known as NUMA1) (Du et al., 2001; Du and Macara, α spindle positioning.
    [Show full text]
  • Expression of Ezrin, CD44, and VEGF in Giant Cell Tumor of Bone and Its
    Zhang et al. World Journal of Surgical Oncology (2015) 13:168 DOI 10.1186/s12957-015-0579-5 WORLD JOURNAL OF SURGICAL ONCOLOGY RESEARCH Open Access Expression of ezrin, CD44, and VEGF in giant cell tumor of bone and its significance Jing Zhang1†, Jian Dong1†, Zuozhang Yang1*†, Xiang Ma1†, Jinlei Zhang1†, Mei Li2, Yun Chen2, Yingying Ding3, Kun Li3 and Zhiping Zhang3 Abstract Background: This research aimed to study the role of ezrin, CD44, and VEGF in invasion, metastasis, recurrence, and prognosis of giant cell tumor of bone (GCTB) and its association with the clinical and pathological features of GCTB. Methods: Expression status of ezrin, CD44, and VEGF in 80 GCTB tissues and its adjacent noncancerous tissue samples were measured with immunohistochemical and Elivison staining. Their correlation with the clinical and pathologic factors was statistically analyzed by chi-square test. Results: The expression status of ezrin, CD44, and VEGF were significantly higher in GCTB tissue samples than in its adjacent noncancerous tissue samples and in GCTB at Campanacci stage III than in Campanacci stages I and II (P < 0.05). No significant difference was found in age and sex of the patients and locations of the tumor (P > 0.05). Survival analysis showed that the expression status of ezrin, CD44, VEGF, and Campanacci clinical stages of GCTB were positively associated with the survival rate of GCTB patients and negatively associated with ezrin and Campanacci stages of GCTB, indicating that ezrin, CD44, VEGF, and Campanacci clinical stages of GCTB are the independent factors for GCTB. Conclusions: Ezrin, CD44, and VEGF are over-expressed in GCTB tissue and its adjacent noncancerous tissue samples and may play an important role in the occurrence, invasion, metastasis, and recurrence of GCTB.
    [Show full text]
  • Sorting Nexin 27 Regulates the Lysosomal Degradation of Aquaporin-2 Protein in the Kidney Collecting Duct
    cells Article Sorting Nexin 27 Regulates the Lysosomal Degradation of Aquaporin-2 Protein in the Kidney Collecting Duct Hyo-Jung Choi 1,2, Hyo-Ju Jang 1,3, Euijung Park 1,3, Stine Julie Tingskov 4, Rikke Nørregaard 4, Hyun Jun Jung 5 and Tae-Hwan Kwon 1,3,* 1 Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu 41944, Korea; [email protected] (H.-J.C.); [email protected] (H.-J.J.); [email protected] (E.P.) 2 New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Taegu 41061, Korea 3 BK21 Plus KNU Biomedical Convergence Program, Department of Biomedical Science, School of Medicine, Kyungpook National University, Taegu 41944, Korea 4 Department of Clinical Medicine, Aarhus University, Aarhus 8200, Denmark; [email protected] (S.J.T.); [email protected] (R.N.) 5 Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; [email protected] * Correspondence: [email protected]; Tel.: +82-53-420-4825; Fax: +82-53-422-1466 Received: 30 March 2020; Accepted: 11 May 2020; Published: 13 May 2020 Abstract: Sorting nexin 27 (SNX27), a PDZ (Postsynaptic density-95/Discs large/Zonula occludens 1) domain-containing protein, cooperates with a retromer complex, which regulates intracellular trafficking and the abundance of membrane proteins. Since the carboxyl terminus of aquaporin-2 (AQP2c) has a class I PDZ-interacting motif (X-T/S-X-F), the role of SNX27 in the regulation of AQP2 was studied. Co-immunoprecipitation assay of the rat kidney demonstrated an interaction of SNX27 with AQP2.
    [Show full text]
  • Molecular Mechanism of Membrane Targeting by the GRP1 PH Domain
    Supplemental Material can be found at: http://www.jlr.org/cgi/content/full/M800150-JLR200/DC1 Molecular mechanism of membrane targeting by the GRP1 PH domain † † † Ju He,* Rachel M. Haney, ,§ Mohsin Vora, Vladislav V. Verkhusha,** Robert V. Stahelin, ,§ and Tatiana G. Kutateladze1,* Department of Pharmacology,* University of Colorado Health Sciences Center, Aurora, CO; † Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, South Bend, IN; Department of Chemistry and Biochemistry and The Walther Center for Cancer Research,§ University of Notre Dame, South Bend, IN; and Department of Anatomy and Structural Biology,** Downloaded from Albert Einstein College of Medicine, Bronx, NY Abstract The general receptor for phosphoinositides iso- Supplementary key words general receptor for phosphoinositides iso- • • • form 1 (GRP1) is recruited to the plasma membrane in re- form 1 pleckstrin homology domain phosphoinositide phosphati- dylinositol 3,4,5-trisphosphate sponse to activation of phosphoinositide 3-kinases and www.jlr.org accumulation of phosphatidylinositol 3,4,5-trisphosphate ʼ [PtdIns(3,4,5)P3]. GRP1 s pleckstrin homology (PH) do- main recognizes PtdIns(3,4,5)P3 with high specificity and af- The signaling lipid phosphatidylinositol 3,4,5-trisphos- finity, however, the precise mechanism of its association phate [PtdIns(3,4,5)P3] is produced in plasma membranes at Albert Einstein College of Medicine Library on July 14, 2008 with membranes remains unclear. Here, we detail the mo- in response to stimulation of cell surface receptors by lecular basis of membrane anchoring by the GRP1 PH do- growth factors and hormones (1). Class I phosphoinositide main. Our data reveal a multivalent membrane docking (PI) 3-kinases phosphorylate the inositol headgroup of the involving PtdIns(3,4,5)P binding, regulated by pH and fa- 3 relatively abundant phosphatidylinositol 4,5-bisphosphate cilitated by electrostatic interactions with other anionic lip- [Ptdns(4,5)P2], transiently elevating the level of PtdIns ids.
    [Show full text]
  • The PX Domain Protein Interaction Network in Yeast
    The PX domain protein interaction network in yeast Zur Erlangung des akademischen Grades eines DOKTORS DER NATURWISSENSCHAFTEN (Dr. rer. nat.) der Fakultät für Chemie und Biowissenschaften der Universität Karlsruhe (TH) vorgelegte DISSERTATION von Dipl. Biol. Carolina S. Müller aus Buenos Aires Dekan: Prof. Dr. Manfred Kappes Referent: Dr. Nils Johnsson Korreferent: HD. Dr. Adam Bertl Tag der mündlichen Prüfung: 17.02.2005 I dedicate this work to my Parents and Alex TABLE OF CONTENTS Table of contents Introduction 1 Yeast as a model organism in proteome analysis 1 Protein-protein interactions 2 Protein Domains in Yeast 3 Classification of protein interaction domains 3 Phosphoinositides 5 Function 5 Structure 5 Biochemistry 6 Localization 7 Lipid Binding Domains 8 The PX domain 10 Function of PX domain containing proteins 10 PX domain structure and PI binding affinities 10 Yeast PX domain containing proteins 13 PX domain and protein-protein interactions 13 Lipid binding domains and protein-protein interactions 14 The PX-only proteins Grd19p and Ypt35p and their phenotypes 15 Aim of my PhD work 16 Project outline 16 Searching for interacting partners 16 Confirmation of obtained interactions via a 16 second independent method Mapping the interacting region 16 The Two-Hybrid System 17 Definition 17 Basic Principle of the classical Yeast-Two Hybrid System 17 Peptide Synthesis 18 SPOT synthesis technique 18 Analysis of protein- peptide contact sites based on SPOT synthesis 19 TABLE OF CONTENTS Experimental procedures 21 Yeast two-hybrid assay
    [Show full text]
  • Adhesion Transendothelial Migration Without Affecting VCAM-1 Inhibits
    An Antibody to the Sixth Ig-like Domain of VCAM-1 Inhibits Leukocyte Transendothelial Migration without Affecting Adhesion This information is current as of September 28, 2021. Sukmook Lee, Il-Hee Yoon, Aerin Yoon, Joan M. Cook-Mills, Chung-Gyu Park and Junho Chung J Immunol published online 1 October 2012 http://www.jimmunol.org/content/early/2012/10/01/jimmun ol.1103803 Downloaded from Why The JI? Submit online. http://www.jimmunol.org/ • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average by guest on September 28, 2021 Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2012 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. Published October 1, 2012, doi:10.4049/jimmunol.1103803 The Journal of Immunology An Antibody to the Sixth Ig-like Domain of VCAM-1 Inhibits Leukocyte Transendothelial Migration without Affecting Adhesion Sukmook Lee,*,1,2 Il-Hee Yoon,*,†,1 Aerin Yoon,‡ Joan M. Cook-Mills,x Chung-Gyu Park,†,3 and Junho Chung‡,3 VCAM-1 plays a key role in leukocyte trafficking during inflammatory responses.
    [Show full text]
  • Polarity: Merlin and Ezrin Get Organized
    RESEARCH HIGHLIGHTS Nature Reviews Cancer | AOP, published online 10 January 2013; doi:10.1038/nrc3453 POLARITY Merlin and ezrin get organized The ezrin, radixin and moesin (ERM) proteins and the closely related tumour suppressor neuro­ fibromatosis type 2 (NF2; also known as merlin) function as scaffolds to organize the cell cortex localization and to help regulate cell polarity of ezrin all during epithelial morphogenesis, around the cell cortex. a process that is often disrupted in Therefore, NF2 seems to tumorigenesis. However, how NF2 be involved in restricting the and the ERM proteins achieve this localization of ezrin, a process organization, and the functional that the authors found requires relationship among these proteins, is α-catenin; this is interesting as it not completely clear. indicates a junction-independent Andrea McClatchey and col­ function for α-catenin. leagues followed the localization of Given the connections of the ezrin and NF2 during the establish­ ezrin cap to the cell cycle, the authors ment of apical–basal polarity in also examined the centrosomes and Lara Crow/NPG single Caco2 intestinal epithelial cells mitotic spindle position in single embedded in Matrigel. They noted Caco2 cells; they found that their (these mice eventually develop renal that ezrin became restricted into localization was tightly correlated carcinomas), and ectopic ezrin a cap-like structure at the plasma with the ezrin cap. Supporting this, localization and multi-layering in the membrane prior to the first cell centrosomes in cells expressing NF2 colon. In addition, cancer cells often division. The cells were uniformly shRNA were found near areas of have extra centrosomes; these can surrounded by extracellular matrix the cortex with ectopic ezrin, and be clustered to allow the cell to form and the cap lacked markers of apical spindles were aberrantly oriented in bipolar spindles, but loss of clustering polarity, indicating that intrinsic these cells.
    [Show full text]
  • Proteomic Analysis of Uterine Fluid During the Pre-Implantation Period of Pregnancy in Cattle
    REPRODUCTIONRESEARCH Proteomic analysis of uterine fluid during the pre-implantation period of pregnancy in cattle Niamh Forde, Paul A McGettigan, Jai P Mehta, Lydia O’Hara, Solomon Mamo, Fuller W Bazer1, Thomas E Spencer2 and Pat Lonergan School of Agriculture and Food Science, University College Dublin, Belfield, Dublin 4, Ireland, 1Department of Animal Science, Texas A&M University, College Station, Texas 77843-2471, USA and 2Department of Animal Sciences, Washington State University, Pullman, Washington 99164-6353, USA Correspondence should be addressed to N Forde; Email: [email protected] Abstract The aims of this study were i) to characterize the global changes in the composition of the uterine luminal fluid (ULF) from pregnant heifers during pregnancy recognition (day 16) using nano-LC MS/MS; ii) to describe quantitative changes in selected proteins in the ULF from days 10, 13, 16 and 19 by Isobaric tags for Relative and Absolute Quantification (iTRAQ) analysis; and iii) to determine whether these proteins are of endometrial or conceptus origin, by examining the expression profiles of the associated transcripts by RNA sequencing. On day 16, 1652 peptides were identified in the ULF by nano-LC MS/MS. Of the most abundant proteins present, iTRAQ analysis revealed that RPB4, TIMP2 and GC had the same expression pattern as IFNT, while the abundance of IDH1, CST6 and GDI2 decreased on either day 16 or 19. ALDOA, CO3, GSN, HSP90A1, SERPINA31 and VCN proteins decreased on day 13 compared with day 10 but subsequently increased on day 16 (P!0.05). Purine nucleoside phosphorylase (PNP) and HSPA8 decreased on day 13, increased on day 16 and decreased and increased on day 19 (P!0.05).
    [Show full text]
  • Sorting Nexin-27 Regulates AMPA Receptor Trafficking Through The
    RESEARCH ARTICLE Sorting nexin-27 regulates AMPA receptor trafficking through the synaptic adhesion protein LRFN2 Kirsty J McMillan1†*, Paul J Banks2†, Francesca LN Hellel1, Ruth E Carmichael1, Thomas Clairfeuille3, Ashley J Evans1, Kate J Heesom4, Philip Lewis4, Brett M Collins3, Zafar I Bashir2, Jeremy M Henley1, Kevin A Wilkinson1*, Peter J Cullen1* 1School of Biochemistry, University of Bristol, Bristol, United Kingdom; 2School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom; 3Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia; 4Proteomics facility, School of Biochemistry, University of Bristol, Bristol, United Kingdom Abstract The endosome-associated cargo adaptor sorting nexin-27 (SNX27) is linked to various neuropathologies through sorting of integral proteins to the synaptic surface, most notably AMPA receptors. To provide a broader view of SNX27-associated pathologies, we performed proteomics in rat primary neurons to identify SNX27-dependent cargoes, and identified proteins linked to excitotoxicity, epilepsy, intellectual disabilities, and working memory deficits. Focusing on the *For correspondence: synaptic adhesion molecule LRFN2, we established that SNX27 binds to LRFN2 and regulates its [email protected] endosomal sorting. Furthermore, LRFN2 associates with AMPA receptors and knockdown of (KJMM); LRFN2 results in decreased surface AMPA receptor expression, reduced synaptic activity, and [email protected] attenuated hippocampal long-term potentiation. Overall, our study provides an additional (KAW); mechanism by which SNX27 can control AMPA receptor-mediated synaptic transmission and [email protected] (PJC) plasticity indirectly through the sorting of LRFN2 and offers molecular insight into the perturbed †These authors contributed function of SNX27 and LRFN2 in a range of neurological conditions.
    [Show full text]
  • Endothelial Cells Transcription in Rhoa and Fos Stimulates C- but Not ICAM
    Intercellular Adhesion Molecule (ICAM)-1, But Not ICAM-2, Activates RhoA and Stimulates c-fos and rhoA Transcription in Endothelial Cells This information is current as of September 25, 2021. Paul W. Thompson, Anna M. Randi and Anne J. Ridley J Immunol 2002; 169:1007-1013; ; doi: 10.4049/jimmunol.169.2.1007 http://www.jimmunol.org/content/169/2/1007 Downloaded from References This article cites 38 articles, 19 of which you can access for free at: http://www.jimmunol.org/content/169/2/1007.full#ref-list-1 http://www.jimmunol.org/ Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication by guest on September 25, 2021 *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2002 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Intercellular Adhesion Molecule (ICAM)-1, But Not ICAM-2, Activates RhoA and Stimulates c-fos and rhoA Transcription in Endothelial Cells1 Paul W. Thompson,*† Anna M. Randi,‡ and Anne J. Ridley2*† ICAM-1 and -2 are integrin-binding Ig superfamily adhesion molecules that are important for leukocyte transmigration across endothelial monolayers.
    [Show full text]