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Miletic AV, Graham DB, Sakata-Sogawa K, Hiroshima M, Hamann MJ, Cemerski S, Kloeppel T, Billadeau DD, Kanagawa O, Tokunaga M, Swat W. Vav links the T cell antigen receptor to the actin cytoskeleton and T cell activation independently of intrinsic Guanine nucleotide exchange activity. PLoS One 2009; 4:e6599. [PMID: 19672294 PMCID: PMC2719804 DOI: 10.1371/journal.pone.0006599] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2009] [Accepted: 07/09/2009] [Indexed: 12/19/2022] Open
Abstract
Background T cell receptor (TCR) engagement leads to formation of signaling microclusters and induction of rapid and dynamic changes in the actin cytoskeleton, although the exact mechanism by which the TCR initiates actin polymerization is incompletely understood. The Vav family of guanine nucleotide exchange factors (GEF) has been implicated in generation of TCR signals and immune synapse formation, however, it is currently not known if Vav's GEF activity is required in T cell activation by the TCR in general, and in actin polymerization downstream of the TCR in particular. Methodology/Principal Findings Here, we report that Vav1 assembles into signaling microclusters at TCR contact sites and is critical for TCR-initiated actin polymerization. Surprisingly, Vav1 functions in TCR signaling and Ca++ mobilization via a mechanism that does not appear to strictly depend on the intrinsic GEF activity. Conclusions/Significance We propose here a model in which Vav functions primarily as a tyrosine phosphorylated linker-protein for TCR activation of T cells. Our results indicate that, contrary to expectations based on previously published studies including from our own laboratory, pharmacological inhibition of Vav1's intrinsic GEF activity may not be an effective strategy for T cell-directed immunosuppressive therapy.
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Affiliation(s)
- Ana V. Miletic
- Department of Pathology and Immunology, Washington University School of Medicine and Siteman Cancer Center, St. Louis, Missouri, United States of America
| | - Daniel B. Graham
- Department of Pathology and Immunology, Washington University School of Medicine and Siteman Cancer Center, St. Louis, Missouri, United States of America
| | - Kumiko Sakata-Sogawa
- Research Unit for Single Molecule Immunoimaging, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa, Japan
| | - Michio Hiroshima
- Research Unit for Single Molecule Immunoimaging, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa, Japan
| | - Michael J. Hamann
- Department of Immunology and Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Saso Cemerski
- Department of Pathology and Immunology, Washington University School of Medicine and Siteman Cancer Center, St. Louis, Missouri, United States of America
| | - Tracie Kloeppel
- Department of Pathology and Immunology, Washington University School of Medicine and Siteman Cancer Center, St. Louis, Missouri, United States of America
| | - Daniel D. Billadeau
- Department of Immunology and Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, Minnesota, United States of America
| | - Osami Kanagawa
- Laboratory for Autoimmune Regulation, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa, Japan
| | - Makio Tokunaga
- Research Unit for Single Molecule Immunoimaging, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa, Japan
- Structural Biology Center, National Institute of Genetics, The Graduate University for Advanced Studies, Mishima, Shizuoka, Japan
- Department of Genetics, The Graduate University for Advanced Studies, Mishima, Shizuoka, Japan
| | - Wojciech Swat
- Department of Pathology and Immunology, Washington University School of Medicine and Siteman Cancer Center, St. Louis, Missouri, United States of America
- * E-mail:
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Stephenson LM, Sammut B, Graham DB, Chan-Wang J, Brim KL, Huett AS, Miletic AV, Kloeppel T, Landry A, Xavier R, Swat W. DLGH1 is a negative regulator of T-lymphocyte proliferation. Mol Cell Biol 2007; 27:7574-81. [PMID: 17724087 PMCID: PMC2169038 DOI: 10.1128/mcb.00439-07] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Discs large homolog 1 (DLGH1), a founding member of the membrane-associated guanylate kinase family of proteins containing PostSynaptic Density-95/Discs large/Zona Occludens-1 domains, is an ortholog of the Drosophila tumor suppressor gene Discs large. In the mammalian embryo, DLGH1 is essential for normal urogenital morphogenesis and the development of skeletal and epithelial structures. Recent reports also indicate that DLGH1 may be a critical mediator of signals triggered by the antigen receptor complex in T lymphocytes by functioning as a scaffold coordinating the activities of T-cell receptor (TCR) signaling proteins at the immune synapse. However, it remains unclear if DLGH1 functions to enhance or attenuate signals emanating from the TCR. Here, we used Dlgh1 gene-targeted mice to determine the requirement for DLGH1 in T-cell development and activation. Strikingly, while all major subsets of T cells appear to undergo normal thymic development in the absence of DLGH1, peripheral lymph node Dlgh1(-/-) T cells show a hyper-proliferative response to TCR-induced stimulation. These data indicate that, consistent with the known function of Discs large proteins as tumor suppressors and attenuators of cell division, in T lymphocytes, DLGH1 functions as a negative regulator of TCR-induced proliferative responses.
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Affiliation(s)
- Linda M Stephenson
- Department of Pathology and Immunology, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110, USA.
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Miletic AV, Graham DB, Montgrain V, Fujikawa K, Kloeppel T, Brim K, Weaver B, Schreiber R, Xavier R, Swat W. Vav proteins control MyD88-dependent oxidative burst. Blood 2007; 109:3360-8. [PMID: 17158234 PMCID: PMC1852252 DOI: 10.1182/blood-2006-07-033662] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 11/30/2006] [Indexed: 12/20/2022] Open
Abstract
The importance of reactive oxygen intermediate (ROI) production in antimicrobial responses is demonstrated in human patients who suffer from chronic granulomatous disease (CGD) due to defective NADPH oxidase function. Exactly how bacterial products activating Toll-like receptors (TLRs) induce oxidative burst is unknown. Here, we identify the Vav family of Rho guanine nucleotide exchange factors (GEFs) as critical mediators of LPS-induced MyD88-dependent activation of Rac2, NADPH oxidase, and ROI production using mice deficient in Vav1, Vav2, and Vav3. Vav proteins are also required for p38 MAPK activation and for normal regulation of proinflammatory cytokine production, but not for other MyD88-controlled effector pathways such as those involving JNK, COX2, or iNOS and the production of reactive nitrogen intermediates (RNIs). Thus, our data indicate that Vav specifically transduces a subset of signals emanating from MyD88.
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Affiliation(s)
- Ana V Miletic
- Department of Pathology and Immunology, Washington University School of Medicine and Siteman Cancer Center, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
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Abstract
Plasma cell (PC) development is initiated following B cell activation and controlled by a B lymphocyte-induced maturation protein (Blimp)-1-dependent program involving the concerted action of several proplasma transcriptional regulators. However, the factors that control Blimp-1 expression remain largely unknown. In this context, mice deficient for all three of the Vav family of proteins (Vav(null)) develop substantial B cell populations, including marginal zone B cells, yet have a virtual absence of serum Igs, indicating that Vav may be specifically required in PC development and Ig production. We show in this study that mature marginal zone B cells from Vav(null) mice proliferate following stimulation with TLR ligands but exhibit severe defects in PC differentiation and Ig secretion. Under conditions inducing PC differentiation, Vav(null) B cells fail to efficiently induce Blimp-1, X box-binding protein-1, J chain, or secretory Ig mu transcripts but express IFN-regulatory factor-4 at levels similar to wild-type cells. These data indicate a previously unknown role for Vav as an upstream regulator of Blimp-1.
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Affiliation(s)
- Linda M Stephenson
- Department of Pathology and Immunology, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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Miletic AV, Sakata-Sogawa K, Hiroshima M, Hamann MJ, Gomez TS, Ota N, Kloeppel T, Kanagawa O, Tokunaga M, Billadeau DD, Swat W. Vav1 acidic region tyrosine 174 is required for the formation of T cell receptor-induced microclusters and is essential in T cell development and activation. J Biol Chem 2006; 281:38257-65. [PMID: 17050525 PMCID: PMC1876972 DOI: 10.1074/jbc.m608913200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vav proteins are multidomain signaling molecules critical for mediating signals downstream of several surface receptors, including the antigen receptors of T and B lymphocytes. The catalytic guanine nucleotide exchange factor (GEF) activity of the Vav Dbl homology (DH) domain is thought to be controlled by an intramolecular autoinhibitory mechanism involving an N-terminal extension and phosphorylation of tyrosine residues in the acidic region (AC). Here, we report that the sequences surrounding the Vav1 AC: Tyr(142), Tyr(160), and Tyr(174) are evolutionarily conserved, conform to consensus SH2 domain binding motifs, and bind several proteins implicated in TCR signaling, including Lck, PI3K p85alpha, and PLCgamma1, through direct interactions with their SH2 domains. In addition, the AC tyrosines regulate tyrosine phosphorylation of Vav1. We also show that Tyr(174) is required for the maintenance of TCR-signaling microclusters and for normal T cell development and activation. In this regard, our data demonstrate that while Vav1 Tyr(174) is essential for maintaining the inhibitory constraint of the DH domain in both developing and mature T cells, constitutively activated Vav GEF disrupts TCR-signaling microclusters and leads to defective T cell development and proliferation.
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Affiliation(s)
- Ana V. Miletic
- From the Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, the
| | - Kumiko Sakata-Sogawa
- Research Unit for Single Molecule Immunoimaging, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045, Japan, the
| | - Michio Hiroshima
- Research Unit for Single Molecule Immunoimaging, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045, Japan, the
| | - Michael J. Hamann
- Department of Immunology and Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, the
| | - Timothy S. Gomez
- Department of Immunology and Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, the
| | - Naruhisa Ota
- Laboratory for Autoimmune Regulation, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045, Japan, and the
| | - Tracie Kloeppel
- From the Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, the
| | - Osami Kanagawa
- Laboratory for Autoimmune Regulation, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045, Japan, and the
| | - Makio Tokunaga
- Research Unit for Single Molecule Immunoimaging, RIKEN Center for Allergy and Immunology, Yokohama, Kanagawa 230-0045, Japan, the
- Structural Biology Center, National Institute of Genetics, and Department of Genetics, Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan
| | - Daniel D. Billadeau
- Department of Immunology and Division of Oncology Research, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, the
| | - Wojciech Swat
- From the Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri 63110, the
- To whom correspondence should be addressed: Dept. of Pathology and Immunology, WA University School of Medicine, 660 S. Euclid Ave., St. Louis, MO 63110. Tel.: 314-747-8886; Fax: 314-362-4096; E-mail:
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Graham DB, Cella M, Giurisato E, Fujikawa K, Miletic AV, Kloeppel T, Brim K, Takai T, Shaw AS, Colonna M, Swat W. Vav1 controls DAP10-mediated natural cytotoxicity by regulating actin and microtubule dynamics. J Immunol 2006; 177:2349-55. [PMID: 16887996 DOI: 10.4049/jimmunol.177.4.2349] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The NK cell-activating receptor NKG2D recognizes several MHC class I-related molecules expressed on virally infected and tumor cells. Human NKG2D transduces activation signals exclusively via an associated DAP10 adaptor containing a YxNM motif, whereas murine NKG2D can signal through either DAP10 or the DAP12 adaptor, which contains an ITAM sequence. DAP10 signaling is thought to be mediated, at least in part, by PI3K and is independent of Syk/Zap-70 kinases; however, the exact mechanism by which DAP10 induces natural cytotoxicity is incompletely understood. Herein, we identify Vav1, a Rho GTPase guanine nucleotide exchange factor, as a critical signaling mediator downstream of DAP10 in NK cells. Specifically, using mice deficient in Vav1 and DAP12, we demonstrate an essential role for Vav1 in DAP10-induced NK cell cytoskeletal polarization involving both actin and microtubule networks, maturation of the cytolytic synapse, and target cell lysis. Mechanistically, we show that Vav1 interacts with DAP10 YxNM motifs through the adaptor protein Grb2 and is required for activation of PI3K-dependent Akt signaling. Based on these findings, we propose a novel model of ITAM-independent signaling by Vav downstream of DAP10 in NK cells.
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MESH Headings
- Actins/metabolism
- Animals
- Cells, Cultured
- Cytotoxicity, Immunologic/genetics
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Membrane Proteins/deficiency
- Membrane Proteins/genetics
- Membrane Proteins/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microtubules/metabolism
- NK Cell Lectin-Like Receptor Subfamily K
- Proto-Oncogene Proteins c-vav/deficiency
- Proto-Oncogene Proteins c-vav/genetics
- Proto-Oncogene Proteins c-vav/physiology
- Receptors, Immunologic/deficiency
- Receptors, Immunologic/genetics
- Receptors, Immunologic/physiology
- Receptors, Natural Killer Cell
- Signal Transduction/immunology
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Affiliation(s)
- Daniel B Graham
- Department of Pathology and Immunology, Washington University School of Medicine and Siteman Cancer Center, 660 South Euclid Avenue, St. Louis, MO 63110, USA
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