1
|
Masi I, Ottavi F, Del Rio D, Caprara V, Vastarelli C, Giannitelli SM, Fianco G, Mozetic P, Buttarelli M, Ferrandina G, Scambia G, Gallo D, Rainer A, Bagnato A, Spadaro F, Rosanò L. The interaction of β-arrestin1 with talin1 driven by endothelin A receptor as a feature of α5β1 integrin activation in high-grade serous ovarian cancer. Cell Death Dis 2023; 14:73. [PMID: 36717550 PMCID: PMC9886921 DOI: 10.1038/s41419-023-05612-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 01/19/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023]
Abstract
Dissemination of high-grade serous ovarian cancer (HG-SOC) in the omentum and intercalation into a mesothelial cell (MC) monolayer depends on functional α5β1 integrin (Intα5β1) activity. Although the binding of Intα5β1 to fibronectin drives these processes, other molecular mechanisms linked to integrin inside-out signaling might support metastatic dissemination. Here, we report a novel interactive signaling that contributes to Intα5β1 activation and accelerates tumor cells toward invasive disease, involving the protein β-arrestin1 (β-arr1) and the activation of the endothelin A receptor (ETAR) by endothelin-1 (ET-1). As demonstrated in primary HG-SOC cells and SOC cell lines, ET-1 increased Intβ1 and downstream FAK/paxillin activation. Mechanistically, β-arr1 directly interacts with talin1 and Intβ1, promoting talin1 phosphorylation and its recruitment to Intβ1, thus fueling integrin inside-out activation. In 3D spheroids and organotypic models mimicking the omentum, ETAR/β-arr1-driven Intα5β1 signaling promotes the survival of cell clusters, with mesothelium-intercalation capacity and invasive behavior. The treatment with the antagonist of ETAR, Ambrisentan (AMB), and of Intα5β1, ATN161, inhibits ET-1-driven Intα5β1 activity in vitro, and tumor cell adhesion and spreading to intraperitoneal organs and Intβ1 activity in vivo. As a prognostic factor, high EDNRA/ITGB1 expression correlates with poor HG-SOC clinical outcomes. These findings highlight a new role of ETAR/β-arr1 operating an inside-out integrin activation to modulate the metastatic process and suggest that in the new integrin-targeting programs might be considered that ETAR/β-arr1 regulates Intα5β1 functional pathway.
Collapse
Affiliation(s)
- Ilenia Masi
- Institute of Molecular Biology and Pathology, CNR, Rome, 00185, Italy
| | - Flavia Ottavi
- Institute of Molecular Biology and Pathology, CNR, Rome, 00185, Italy
| | - Danila Del Rio
- Institute of Molecular Biology and Pathology, CNR, Rome, 00185, Italy
| | - Valentina Caprara
- Unit of Preclinical Models and New Therapeutic Agents, IRCCS-Regina Elena National Cancer Institute, Rome, 00144, Italy
| | | | - Sara Maria Giannitelli
- Department of Engineering, Università Campus Bio-Medico di Roma, via Álvaro del Portillo 21, Rome, 00128, Italy
| | - Giulia Fianco
- Institute of Molecular Biology and Pathology, CNR, Rome, 00185, Italy
| | - Pamela Mozetic
- Institute of Nanotechnology (NANOTEC), National Research Council (CNR), c/o Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
- San Raffaele Hospital, Division of Neuroscience, Institute of Experimental Neurology, San Raffaele Scientific Institute, Via Olgettina, 60, Milan, 20132, Italy
| | - Marianna Buttarelli
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica-Sezione di Ginecologia ed Ostetricia-Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, Rome, 00168, Italy
- Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Largo A. Gemelli 8, Rome, 00168, Italy
| | - Gabriella Ferrandina
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica-Sezione di Ginecologia ed Ostetricia-Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, Rome, 00168, Italy
- Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Largo A. Gemelli 8, Rome, 00168, Italy
| | - Giovanni Scambia
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica-Sezione di Ginecologia ed Ostetricia-Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, Rome, 00168, Italy
- Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Largo A. Gemelli 8, Rome, 00168, Italy
| | - Daniela Gallo
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica-Sezione di Ginecologia ed Ostetricia-Università Cattolica del Sacro Cuore, Largo A. Gemelli 8, Rome, 00168, Italy
- Dipartimento Scienze della Salute della Donna, del Bambino e di Sanità Pubblica, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Largo A. Gemelli 8, Rome, 00168, Italy
| | - Alberto Rainer
- Department of Engineering, Università Campus Bio-Medico di Roma, via Álvaro del Portillo 21, Rome, 00128, Italy
- Institute of Nanotechnology (NANOTEC), National Research Council (CNR), c/o Campus Ecotekne, via Monteroni, Lecce, 73100, Italy
| | - Anna Bagnato
- Unit of Preclinical Models and New Therapeutic Agents, IRCCS-Regina Elena National Cancer Institute, Rome, 00144, Italy
| | - Francesca Spadaro
- Confocal Microscopy Unit, Core Facilities, Istituto Superiore di Sanità, Rome, 00161, Italy
| | - Laura Rosanò
- Institute of Molecular Biology and Pathology, CNR, Rome, 00185, Italy.
- Unit of Preclinical Models and New Therapeutic Agents, IRCCS-Regina Elena National Cancer Institute, Rome, 00144, Italy.
| |
Collapse
|
2
|
Mastrogiovanni M, Juzans M, Alcover A, Di Bartolo V. Coordinating Cytoskeleton and Molecular Traffic in T Cell Migration, Activation, and Effector Functions. Front Cell Dev Biol 2020; 8:591348. [PMID: 33195256 PMCID: PMC7609836 DOI: 10.3389/fcell.2020.591348] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 09/24/2020] [Indexed: 12/28/2022] Open
Abstract
Dynamic localization of receptors and signaling molecules at the plasma membrane and within intracellular vesicular compartments is crucial for T lymphocyte sensing environmental cues, triggering membrane receptors, recruiting signaling molecules, and fine-tuning of intracellular signals. The orchestrated action of actin and microtubule cytoskeleton and intracellular vesicle traffic plays a key role in all these events that together ensure important steps in T cell physiology. These include extravasation and migration through lymphoid and peripheral tissues, T cell interactions with antigen-presenting cells, T cell receptor (TCR) triggering by cognate antigen–major histocompatibility complex (MHC) complexes, immunological synapse formation, cell activation, and effector functions. Cytoskeletal and vesicle traffic dynamics and their interplay are coordinated by a variety of regulatory molecules. Among them, polarity regulators and membrane–cytoskeleton linkers are master controllers of this interplay. Here, we review the various ways the T cell plasma membrane, receptors, and their signaling machinery interplay with the actin and microtubule cytoskeleton and with intracellular vesicular compartments. We highlight the importance of this fine-tuned crosstalk in three key stages of T cell biology involving cell polarization: T cell migration in response to chemokines, immunological synapse formation in response to antigen cues, and effector functions. Finally, we discuss two examples of perturbation of this interplay in pathological settings, such as HIV-1 infection and mutation of the polarity regulator and tumor suppressor adenomatous polyposis coli (Apc) that leads to familial polyposis and colorectal cancer.
Collapse
Affiliation(s)
- Marta Mastrogiovanni
- Ligue Nationale Contre le Cancer - Equipe Labellisée LIGUE 2018, Lymphocyte Cell Biology Unit, INSERM-U1221, Department of Immunology, Institut Pasteur, Paris, France.,Collège Doctoral, Sorbonne Université, Paris, France
| | - Marie Juzans
- Ligue Nationale Contre le Cancer - Equipe Labellisée LIGUE 2018, Lymphocyte Cell Biology Unit, INSERM-U1221, Department of Immunology, Institut Pasteur, Paris, France
| | - Andrés Alcover
- Ligue Nationale Contre le Cancer - Equipe Labellisée LIGUE 2018, Lymphocyte Cell Biology Unit, INSERM-U1221, Department of Immunology, Institut Pasteur, Paris, France
| | - Vincenzo Di Bartolo
- Ligue Nationale Contre le Cancer - Equipe Labellisée LIGUE 2018, Lymphocyte Cell Biology Unit, INSERM-U1221, Department of Immunology, Institut Pasteur, Paris, France
| |
Collapse
|
3
|
Kuropka B, Schraven B, Kliche S, Krause E, Freund C. Tyrosine-phosphorylation of the scaffold protein ADAP and its role in T cell signaling. Expert Rev Proteomics 2017; 13:545-54. [PMID: 27258783 DOI: 10.1080/14789450.2016.1187565] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION The Adhesion and Degranulation promoting Adaptor Protein (ADAP) is phosphorylated upon T cell activation and acts as a scaffold for the formation of a signaling complex that integrates molecular interactions between T cell or chemokine receptors, the actin cytoskeleton, and integrin-mediated cellular adhesion and migration. AREAS COVERED This article reviews current knowledge of the functions of the adapter protein ADAP in T cell signaling with a focus on the role of individual phosphotyrosine (pY) motifs for SH2 domain mediated interactions. The data presented was obtained from literature searches (PubMed) as well as the authors own research on the topic. Expert commentary: ADAP can be regarded as a paradigmatic example of how tyrosine phosphorylation sites serve as dynamic interaction hubs. Molecular crowding at unstructured and redundant sites (pY595, pY651) is contrasted by more specific interactions enabled by the three-dimensional environment of a particular phosphotyrosine motif (pY571).
Collapse
Affiliation(s)
- Benno Kuropka
- a Freie Universität Berlin, Institut für Chemie und Biochemie, Protein Biochemistry Group , Berlin , Germany.,b Mass Spectrometry Group, Leibniz-Institut für Molekulare Pharmakologie , Berlin , Germany
| | - Burkhart Schraven
- c Institute of Molecular and Clinical Immunology , Otto-von-Guericke-University , Magdeburg , Germany.,d Department of Immune Control , Helmholtz Center for Infection Research (HZI) , Braunschweig , Germany
| | - Stefanie Kliche
- c Institute of Molecular and Clinical Immunology , Otto-von-Guericke-University , Magdeburg , Germany
| | - Eberhard Krause
- b Mass Spectrometry Group, Leibniz-Institut für Molekulare Pharmakologie , Berlin , Germany
| | - Christian Freund
- a Freie Universität Berlin, Institut für Chemie und Biochemie, Protein Biochemistry Group , Berlin , Germany
| |
Collapse
|
4
|
Anderson LR, Owens TW, Naylor MJ. Structural and mechanical functions of integrins. Biophys Rev 2014; 6:203-213. [PMID: 28510180 PMCID: PMC5418412 DOI: 10.1007/s12551-013-0124-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/28/2013] [Indexed: 01/09/2023] Open
Abstract
Integrins are ubiquitously expressed cell surface receptors that play a critical role in regulating the interaction between a cell and its microenvironment to control cell fate. These molecules are regulated either via their expression on the cell surface or through a unique bidirectional signalling mechanism. However, integrins are just the tip of the adhesome iceberg, initiating the assembly of a large range of adaptor and signalling proteins that mediate the structural and signalling functions of integrin. In this review, we summarise the structure of integrins and mechanisms by which integrin activation is controlled. The different adhesion structures formed by integrins are discussed, as well as the mechanical and structural roles integrins play during cell migration. As the function of integrin signalling can be quite varied based on cell type and context, an in depth understanding of these processes will aid our understanding of aberrant adhesion and migration, which is often associated with human pathologies such as cancer.
Collapse
Affiliation(s)
- Luke R Anderson
- Discipline of Physiology & Bosch Institute, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Thomas W Owens
- Discipline of Physiology & Bosch Institute, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Matthew J Naylor
- Discipline of Physiology & Bosch Institute, School of Medical Sciences, The University of Sydney, Sydney, NSW, Australia.
- The University of Sydney, Room E212, Anderson Stuart Building (F13), Sydney, NSW, 2006, Australia.
| |
Collapse
|
5
|
Liu J, Fu T, Peng B, Sun H, Chu H, Li G, Chen J. The hydrophobic contacts between the center of the βI domain and the α1/α7 helices are crucial for the low-affinity state of integrin α4 β7. FEBS J 2014; 281:2915-26. [PMID: 24802248 DOI: 10.1111/febs.12829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 04/21/2014] [Accepted: 05/01/2014] [Indexed: 11/28/2022]
Abstract
Integrin α4 β7 mediates both rolling and firm adhesion of lymphocytes by modulating its affinity to the ligand: mucosal addressin cell adhesion molecule-1 (MAdCAM-1). Integrin activation is associated with allosteric reshaping in the β subunit I (βI) domain. A prominently conformational change comprises displacement of the α1 and α7 helices in the βI domain, suggesting that the location of these helices is important for the change in integrin affinity. In the present study, we report that the hydrophobic contacts between the center of the β7 I domain and the α1/α7 helices play critical roles in keeping α4 β7 in a low-affinity state. Using molecular dynamics simulation, we identified nine hydrophobic residues that might be involved in the critical hydrophobic contacts maintaining integrin in a low-affinity state. Integrin β7 I domain exhibited a lower binding free energy for ligand after disrupting these hydrophobic contacts by substituting the hydrophobic residues with Ala. Moreover, these α4 β7 mutants not only showed high-affinity binding to soluble MAdCAM-1, but also demonstrated firm cell adhesion to immobilized MAdCAM-1 in shear flow and enhanced the strength of the α4 β7 -MAdCAM-1 interaction. Disruption of the hydrophobic contacts also induced the active conformation of α4 β7 . Thus, the findings obtained in the present study reveal an important structural basis for the low-affinity state of integrin.
Collapse
Affiliation(s)
- Jie Liu
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, China
| | | | | | | | | | | | | |
Collapse
|
6
|
Shulman Z, Cohen SJ, Roediger B, Kalchenko V, Jain R, Grabovsky V, Klein E, Shinder V, Stoler-Barak L, Feigelson SW, Meshel T, Nurmi SM, Goldstein I, Hartley O, Gahmberg CG, Etzioni A, Weninger W, Ben-Baruch A, Alon R. Transendothelial migration of lymphocytes mediated by intraendothelial vesicle stores rather than by extracellular chemokine depots. Nat Immunol 2011; 13:67-76. [PMID: 22138716 DOI: 10.1038/ni.2173] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Accepted: 10/25/2011] [Indexed: 12/11/2022]
Abstract
Chemokines presented by the endothelium are critical for integrin-dependent adhesion and transendothelial migration of naive and memory lymphocytes. Here we found that effector lymphocytes of the type 1 helper T cell (T(H)1 cell) and type 1 cytotoxic T cell (T(C)1 cell) subtypes expressed adhesive integrins that bypassed chemokine signals and established firm arrests on variably inflamed endothelial barriers. Nevertheless, the transendothelial migration of these lymphocytes strictly depended on signals from guanine nucleotide-binding proteins of the G(i) type and was promoted by multiple endothelium-derived inflammatory chemokines, even without outer endothelial surface exposure. Instead, transendothelial migration-promoting endothelial chemokines were stored in vesicles docked on actin fibers beneath the plasma membranes and were locally released within tight lymphocyte-endothelial synapses. Thus, effector T lymphocytes can cross inflamed barriers through contact-guided consumption of intraendothelial chemokines without surface-deposited chemokines or extraendothelial chemokine gradients.
Collapse
Affiliation(s)
- Ziv Shulman
- Department of Immunology, Weizmann Institute of Science, Rehovot, Israel
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
Carrard A, Salzmann A, Perroud N, Gafner J, Malafosse A, Karege F. Genetic association of the Phosphoinositide-3 kinase in schizophrenia and bipolar disorder and interaction with a BDNF gene polymorphism. Brain Behav 2011; 1:119-24. [PMID: 22399091 PMCID: PMC3236546 DOI: 10.1002/brb3.23] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Revised: 08/08/2011] [Accepted: 09/10/2011] [Indexed: 01/14/2023] Open
Abstract
Phosphoinositide-3-kinase, class III (PIK3C3) is a member of the phosphoinosite-3-kinases family, involved in cell signaling, membrane trafficking, and neurodevelopment. Previous studies have indeed shown an association between PIK3C3 gene variants and both bipolar disorder (BD) and schizophrenia (SZ). Brain-derived neurotrophic factor (BDNF) is a neurodevelopmental factor, which can regulate the PI3K signaling pathway. Associations have been reported between BDNF gene polymorphisms and affective and psychotic disorders. The aim of the present study was to replicate an association between PIK3C3 and BDNF gene variants in SZ and BD and a putative epistasis between the two genes. Patients meeting the DSM-IV criteria of BD and SZ were included in this study (98 BD and 79 SZ) as well as 158 healthy controls. Blood DNA was extracted and genotyping was performed either by the polymerase chain reaction (PCR) technique followed by enzymatic digestion or by the high-resolution melt (HRM) method. Genotype and haplotype association was assessed with the UNPHASED statistical program.The results showed one nominal association with BD (P < 0.02) and two risk haplotypes in both SZ (P < 0.001) and BP (P < 0.0005), which survived multiple testing correction. A modest interaction between a BDNF variant and PI3KC3 polymorphism was observed (P < 0.04).These preliminary results confirm the genetic association of PI3K gene variants with both SZ and BD, and support the hypothesis that SZ and BD share a genetic background.
Collapse
Affiliation(s)
- Anthony Carrard
- Department of Psychiatry, University of Geneva, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
| | - Annick Salzmann
- Department of Psychiatry, University of Geneva, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
| | - Nader Perroud
- Department of Medical Genetics and Laboratory, Geneva University Hospitals, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
| | - Jérémie Gafner
- Department of Psychiatry, University of Geneva, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
| | - Alain Malafosse
- Department of Psychiatry, University of Geneva, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
- Department of Medical Genetics and Laboratory, Geneva University Hospitals, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
| | - Félicien Karege
- Department of Psychiatry, University of Geneva, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
- Department of Medical Genetics and Laboratory, Geneva University Hospitals, 2 ch Petit Bel‐Air, CH‐1225 Chêne‐Bourg, Geneva, Switzerland
| |
Collapse
|
8
|
Anthis NJ, Campbell ID. The tail of integrin activation. Trends Biochem Sci 2011; 36:191-8. [PMID: 21216149 DOI: 10.1016/j.tibs.2010.11.002] [Citation(s) in RCA: 132] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/29/2010] [Accepted: 11/30/2010] [Indexed: 12/13/2022]
Abstract
Integrins are essential adhesion receptors found on the surfaces of all metazoan cells. As regulators of cell migration and extracellular matrix assembly, these membrane-spanning heterodimers are critical for embryonic development, tissue repair and immune responses. Signals transmitted by integrins from outside to inside the cell promote cell survival and proliferation, but integrin affinity for extracellular ligands can also be controlled by intracellular cues. This bidirectional signaling is mediated by the short cytoplasmic tails of the two integrin subunits. Recent structural and functional studies of various integrin fragments and complexes between the cytoplasmic tails and intracellular proteins, such as talin, have provided new insight into the signaling processes centered around the tails, particularly inside-out integrin activation.
Collapse
Affiliation(s)
- Nicholas J Anthis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA
| | | |
Collapse
|
9
|
Alexandropoulos K, Regelmann AG. Regulation of T-lymphocyte physiology by the Chat-H/CasL adapter complex. Immunol Rev 2010; 232:160-74. [PMID: 19909363 DOI: 10.1111/j.1600-065x.2009.00831.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The Cas family of proteins consists of at least four members implicated in the regulation of diverse cellular processes such as cell proliferation, adhesion, motility, and cancer cell metastasis. Cas family members have conserved C-termini that mediate constitutive heterotypic interactions with members of a different group of proteins, the NSP family. Both the Cas and NSP proteins have conserved domains that mediate protein-protein interactions with other cytoplasmic intermediates. Signaling modules assembled by these proteins in turn regulate signal transduction downstream of a variety of receptors including integrin, chemokine, and antigen receptors. T lymphocytes express the NSP protein NSP3/Chat-H and the Cas protein Hef1/CasL, which are found in a constitutive complex in naive T cells. We recently showed that Chat-H and Hef1/CasL regulate integrin-mediated adhesion and promote T-cell migration and trafficking downstream of activated chemokine receptors. It is currently unclear if the Chat-H/CasL module also plays a role in antigen receptor signaling. Here we review our current knowledge of how Chat-H and Hef1/CasL regulate T-cell physiology and whether this protein complex plays a functional role downstream of T-cell receptor activation.
Collapse
Affiliation(s)
- Konstantina Alexandropoulos
- Department of Medicine, Division of Clinical Immunology, The Immunology Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.
| | | |
Collapse
|
10
|
The adapter protein SLP-76 mediates "outside-in" integrin signaling and function in T cells. Mol Cell Biol 2009; 29:5578-89. [PMID: 19667077 DOI: 10.1128/mcb.00283-09] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The adapter protein SH2 domain-containing leukocyte protein of 76 kDa (SLP-76) is an essential mediator of signaling from the T-cell antigen receptor (TCR). We report here that SLP-76 also mediates signaling downstream of integrins in T cells and that SLP-76-deficient T cells fail to support adhesion to integrin ligands. In response to both TCR and integrin stimulation, SLP-76 relocalizes to surface microclusters that colocalize with phosphorylated signaling proteins. Disruption of SLP-76 recruitment to the protein named LAT (linker for activation of T cells) inhibits SLP-76 clustering downstream of the TCR but not downstream of integrins. Conversely, an SLP-76 mutant unable to bind ADAP (adhesion and degranulation-promoting adapter protein) forms clusters following TCR but not integrin engagement and fails to support T-cell adhesion to integrin ligands. These findings demonstrate that SLP-76 relocalizes to integrin-initiated signaling complexes by a mechanism different from that employed during TCR signaling and that SLP-76 relocalization corresponds to SLP-76-dependent integrin function in T cells.
Collapse
|