201
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Goitsuka R, Kanazashi H, Sasanuma H, Fujimura Y, Hidaka Y, Tatsuno A, Ra C, Hayashi K, Kitamura D. A BASH/SLP-76-related adaptor protein MIST/Clnk involved in IgE receptor-mediated mast cell degranulation. Int Immunol 2000; 12:573-80. [PMID: 10744659 DOI: 10.1093/intimm/12.4.573] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cross-linking of the high-affinity IgE receptor (FcepsilonRI) on mast cells by IgE-antigen complex triggers signal transduction cascades leading to the release of inflammatory mediators and production of cytokines, which are critical for the development of allergic reactions. We have identified a novel member of the BASH/SLP-76 immunoreceptor-coupled adaptor family expressed in mast cells, termed MIST (for mast cell immunoreceptor signal transducer), which has later been found to be identical to a recently reported cytokine-dependent hemopoietic cell linker, Clnk. Upon FcepsilonRI cross-linking, MIST/Clnk is tyrosine phosphorylated and associates with signaling proteins, phospholipase Cgamma, Vav, Grb2 and linker for activation of T cells (LAT). Overexpression of a mutant form of MIST/Clnk inhibited FcepsilonRI-mediated degranulation, increase in intracellular Ca(2+), NF-AT activation and phosphorylation of LAT. As a crucial signaling component for FcepsilonRI-induced mast cell degranulation, MIST/Clnk might serve as a target for anti-allergic therapy.
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Affiliation(s)
- R Goitsuka
- Division of Molecular Biology, Research Institute for Biological Sciences, Science University of Tokyo, 2669 Yamazaki, Noda, Chiba 278, Japan
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202
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Hehner SP, Hofmann TG, Ushmorov A, Dienz O, Wing-Lan Leung I, Lassam N, Scheidereit C, Dröge W, Schmitz ML. Mixed-lineage kinase 3 delivers CD3/CD28-derived signals into the IkappaB kinase complex. Mol Cell Biol 2000; 20:2556-68. [PMID: 10713178 PMCID: PMC85472 DOI: 10.1128/mcb.20.7.2556-2568.2000] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/1999] [Accepted: 12/07/1999] [Indexed: 11/20/2022] Open
Abstract
The phosphorylation of IkappaB by the multiprotein IkappaB kinase complex (IKC) precedes the activation of transcription factor NF-kappaB, a key regulator of the inflammatory response. Here we identified the mixed-lineage group kinase 3 (MLK3) as an activator of NF-kappaB. Expression of the wild-type form of this mitogen-activated protein kinase kinase kinase (MAPKKK) induced nuclear immigration, DNA binding, and transcriptional activity of NF-kappaB. MLK3 directly phosphorylated and thus activated IkappaB kinase alpha (IKKalpha) and IKKbeta, revealing its function as an IkappaB kinase kinase (IKKK). MLK3 cooperated with the other two IKKKs, MEKK1 and NF-kappaB-inducing kinase, in the induction of IKK activity. MLK3 bound to components of the IKC in vivo. This protein-protein interaction was dependent on the central leucine zipper region of MLK3. A kinase-deficient version of MLK3 strongly impaired NF-kappaB-dependent transcription induced by T-cell costimulation but not in response to tumor necrosis factor alpha or interleukin-1. Accordingly, endogenous MLK3 was phosphorylated and activated by T-cell costimulation but not by treatment of cells with tumor necrosis factor alpha or interleukin-1. A dominant negative version of MLK3 inhibited NF-kappaB- and CD28RE/AP-dependent transcription elicited by the Rho family GTPases Rac and Cdc42, thereby providing a novel link between these GTPases and the IKC.
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Affiliation(s)
- S P Hehner
- Department of Immunochemistry, German Cancer Research Center, 69120 Heidelberg, Germany
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203
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Affiliation(s)
- X R Bustelo
- Department of Pathology, State University of New York at Stony Brook, Stony Brook, New York 11794, USA.
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204
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Salojin KV, Zhang J, Meagher C, Delovitch TL. ZAP-70 is essential for the T cell antigen receptor-induced plasma membrane targeting of SOS and Vav in T cells. J Biol Chem 2000; 275:5966-75. [PMID: 10681590 DOI: 10.1074/jbc.275.8.5966] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Translocation of the SOS and Vav GDP/GTP exchange factors proximal to Ras and Rac GTPases localized in the plasma membrane glycolipid-enriched microdomains is a pivotal step required for T cell antigen receptor-induced T cell activation. Here we demonstrate that the T cell antigen receptor zeta-chain-associated ZAP-70 kinase and T cell antigen receptor zeta-chain immunoreceptor tyrosine-based activation motifs are essential for the membrane recruitment of SOS and Vav. Plasma membrane targeting of SOS or Vav begins with the assembly of ZAP-70 with Grb-2 and SOS. The subsequent tyrosine phosphorylation of LAT (linker for activation of T cell) by ZAP-70 leads to a shift in equilibrium from the ZAP-70.Grb-2.SOS(Vav) complex to the (Vav)SOS.Grb-2.LAT complex. This shift results in the targeting of SOS and Vav into glycolipid-enriched microdomains and initiation of the Ras and Rac signaling cascades involved in T cell activation, proliferation, and cytokine production.
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Affiliation(s)
- K V Salojin
- Autoimmunity/Diabetes Group, The John P. Robarts Research Institute, Department of Microbiology, University of Western Ontario, London, Ontario N6G 2V4, Canada
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205
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Hofmann TG, Hehner SP, Dröge W, Schmitz ML. Caspase-dependent cleavage and inactivation of the Vav1 proto-oncogene product during apoptosis prevents IL-2 transcription. Oncogene 2000; 19:1153-63. [PMID: 10713703 DOI: 10.1038/sj.onc.1203406] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Here we identify the hematopoietic proto-oncogene Vav1 as a caspase substrate during apoptosis in lymphoid cells. Cleavage of Vav1 is prevented by the caspase inhibitors zDEVD and zVAD as well as by expression of CrmA. Vav1 is cleaved in vivo at the evolutionary conserved caspase consensus cleavage site DLYD161C, generating the carboxy-terminal cleavage product Vav1p76 of intermediate stability. In vitro caspase assays reveal cleavage of Vav1 at position 161 either by apoptotic cell lysates or by recombinant caspase-3. Mutation of Asp 161 to Ala leads to the usage of the adjacent alternative cleavage sequence DQID150D. Mutation of both cleavage sites at position 150 and 161 protects Vav1 from caspase-mediated proteolysis in vitro and in vivo. The cleavage product Vav1p76 is capable of activating JNK in T-cells, but fails to induce the phosphorylation of p38/HOG1. Vav1p76 displays a diminished capacity to activate the transcription factors NF-AT, AP-1 and NF-kappaB, and thus completely fails to activate IL-2 transcription. Since Vav1 is essential for IL-2 production and plays a central role for cytoskeletal reorganization, its proteolytic inactivation during apoptosis affects multiple downstream targets.
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Affiliation(s)
- T G Hofmann
- German Cancer Research Center (DKFZ), Department of Immunochemistry, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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206
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Sharie N, Arpaia E, Roifman CM. CD8 LYMPHOCYTOPENIA CAUSED BY ZAP-70 DEFICIENCY. Radiol Clin North Am 2000. [DOI: 10.1016/s0033-8389(22)00180-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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207
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Sharfe N, Arpaia E, Roifman CM. CD8 LYMPHOCYTOPENIA CAUSED BY ZAP-70 DEFICIENCY. Immunol Allergy Clin North Am 2000. [DOI: 10.1016/s0889-8561(05)70135-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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208
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Villalba M, Coudronniere N, Deckert M, Teixeiro E, Mas P, Altman A. A novel functional interaction between Vav and PKCtheta is required for TCR-induced T cell activation. Immunity 2000; 12:151-60. [PMID: 10714681 DOI: 10.1016/s1074-7613(00)80168-5] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Vav and PKCtheta play an early and important role in the TCR/CD28-induced stimulation of MAP kinases and activation of the IL-2 gene. Vav is also essential for actin cytoskeleton reorganization and TCR capping. Here, we report that PKCtheta function was selectively required in a Vav signaling pathway that mediates the TCR/CD28-induced activation of JNK and the IL-2 gene and the upregulation of CD69 expression. Vav also promoted PKCtheta translocation from the cytosol to the membrane and cytoskeleton and induced its enzymatic activation in a CD3/CD28-initiated pathway that was dependent on Rac and on actin cytoskeleton reorganization. These findings reveal that the Vav/Rac pathway promotes the recruitment of PKCtheta to the T cell synapse and its activation, essential processes for T cell activation and IL-2 production.
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Affiliation(s)
- M Villalba
- Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San Diego, California 92121, USA
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209
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Kuhne MR, Ku G, Weiss A. A guanine nucleotide exchange factor-independent function of Vav1 in transcriptional activation. J Biol Chem 2000; 275:2185-90. [PMID: 10636924 DOI: 10.1074/jbc.275.3.2185] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
T cell antigen receptor (TCR) stimulation induces the tyrosine phosphorylation of several intracellular proteins including the protooncogene Vav1. Vav1 expression is necessary for normal T cell development and activation. We previously showed that overexpression of Vav1 in Jurkat T cells potentiates the activity of the transcription factor nuclear factor of activated T cells (NF-AT). The mechanism by which Vav1 participates in TCR signaling events is not clear. Vav1 contains a guanine nucleotide exchange factor (GEF) domain that has specificity for Rac and other Rho GTPases that have been recently implicated in T cell activation events. Significantly, in vitro tyrosine phosphoryation of Vav1 by Lck activates its exchange activity. This Lck-mediated phosphorylation of Vav1 has been reported to depend upon Tyr-174 in Vav1, a site implicated in Vav1 function by other studies as well. In this report, we demonstrated that Tyr-174 is not required for the TCR-induced phosphorylation of Vav1 in vivo. Moreover, mutation of Tyr-174 augmented the ability of Vav1 to up-regulate NF-AT activation as well as the Vav1 GEF function leading to Rac activation. However, we also showed that the GEF activity of Vav1 was neither sufficient nor necessary for potentiation of NF-AT, and thereby we identify a GEF-independent role of Vav1 in potentiating NF-AT-driven transcription. Oncogenic Vav1 in which the amino-terminal 67 amino acids were deleted had elevated GEF activity but did not potentiate NF-AT when overexpressed in Jurkat cells. We also showed that a GEF mutant form of Vav1 that had impaired GEF function could still potentiate NF-AT. These studies reveal a previously unrecognized negative regulatory function of Tyr-174 in Vav1 and suggest that domains other than the Vav1 GEF domain contribute to TCR signals leading to NF-AT activation.
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Affiliation(s)
- M R Kuhne
- Departments of Medicine and of Microbiology and Immunology, Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94143, USA
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210
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Arudchandran R, Brown MJ, Peirce MJ, Song JS, Zhang J, Siraganian RP, Blank U, Rivera J. The Src homology 2 domain of Vav is required for its compartmentation to the plasma membrane and activation of c-Jun NH(2)-terminal kinase 1. J Exp Med 2000; 191:47-60. [PMID: 10620604 PMCID: PMC2195799 DOI: 10.1084/jem.191.1.47] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Vav is a hematopoietic cell-specific guanine nucleotide exchange factor (GEF) whose activation is mediated by receptor engagement. The relationship of Vav localization to its function is presently unclear. We found that Vav redistributes to the plasma membrane in response to Fcin receptor I (FcinRI) engagement. The redistribution of Vav was mediated by its Src homology 2 (SH2) domain and required Syk activity. The FcinRI and Vav were found to colocalize and were recruited to glycosphingolipid-enriched microdomains (GEMs). The scaffold protein, linker for activation of T cells (LAT), and Rac1 (a target of Vav activity) were constitutively present in GEMs. Expression of an SH2 domain-containing COOH-terminal fragment of Vav inhibited Vav phosphorylation and movement to the GEMs but had no effect on the tyrosine phosphorylation of the adaptor protein, SLP-76 (SH2 domain-containing leukocyte protein of 76 kD), and LAT. However, assembly of the multiprotein complex containing these proteins was inhibited. In addition, FcinRI-dependent activation of c-Jun NH(2)-terminal kinase 1 (JNK1) was also inhibited. Thus, Vav localization to the plasma membrane is mediated by its SH2 domain and may serve to regulate downstream effectors like JNK1.
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Affiliation(s)
- Ramachandran Arudchandran
- Section on Chemical Immunology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, the
| | | | - Matthew J. Peirce
- Section on Chemical Immunology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, the
| | - James S. Song
- Section on Chemical Immunology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, the
| | - Juan Zhang
- Laboratory of Immunology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892
| | - Reuben P. Siraganian
- Laboratory of Immunology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892
| | | | - Juan Rivera
- Section on Chemical Immunology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, the
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211
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Ouellet M, Barbeau B, Tremblay MJ. p56(lck), ZAP-70, SLP-76, and calcium-regulated effectors are involved in NF-kappaB activation by bisperoxovanadium phosphotyrosyl phosphatase inhibitors in human T cells. J Biol Chem 1999; 274:35029-36. [PMID: 10574981 DOI: 10.1074/jbc.274.49.35029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study investigates the second messengers involved in NF-kappaB activation by the bisperoxovanadium (bpV) phosphotyrosyl phosphatase inhibitors. We first initiated a time course analysis of bpV-mediated activation of the human immunodeficiency virus type-1 long terminal repeat- and NF-kappaB-driven reporter gene. Our results showed a slower and more transient activation of both kappaB-regulated luciferase-encoding vectors by bpV compounds when compared with the action of tumor necrosis factor-alpha (TNF). Time course analyses of NF-kappaB translocation by shift assay experiments further confirmed these results, hence implying distinct pathways of NF-kappaB activation for bpV compounds and TNF. Attempts to characterize the bpV-dependent signaling cascade revealed that the src family protein tyrosine kinase p56(lck) was critical for NF-kappaB induction by bpV. Furthermore, p56(lck) interaction with the intracytoplasmic tail of CD4 markedly enhanced such induction. Optimal activation of NF-kappaB following bpV treatment necessitated downstream effectors of p56(lck) such as the syk family protein tyrosine kinase ZAP-70 and the molecular adaptor SLP-76. Importantly, reduced NF-kappaB activation was observed when capacitative calcium entry was deficient but also upon pharmacological inhibition of calmodulin and calcineurin. Altogether, these results suggest that induction of NF-kappaB by phosphotyrosyl phosphatase bpV inhibitors necessitates both proximal and distal effectors of T cell activation.
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Affiliation(s)
- M Ouellet
- Centre de Recherche en Infectiologie, Centre Hospitalier Universitaire du Québec, Pavillon CHUL and Département de Biologie Médicale, Faculté de Médecine, Université Laval, Sainte-Foy Québec G1V 4G2, Canada
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