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Pawlik A, Malinowski D, Paradowska-Gorycka A, Safranow K, Dziedziejko V. VAV1 Gene Polymorphisms in Patients with Rheumatoid Arthritis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17093214. [PMID: 32380774 PMCID: PMC7246862 DOI: 10.3390/ijerph17093214] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/30/2020] [Accepted: 05/02/2020] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Rheumatoid arthritis (RA) is an important public health problem because this disease often causes disability. RA is a chronic, destructive autoimmune disease that leads to joint destruction and the development of extraarticular manifestations. VAV1 is an intracellular signal transduction protein that plays a significant role in signal transduction in T cells and affects T cell development, proliferation and activation. The VAV1 gene contains 27 exons and is located on chromosome 19. In this study, we examined the association between VAV1 rs2546133 and rs2617822 polymorphisms and RA. METHODS We examined 422 patients with RA and 338 healthy subjects as the control group. RESULTS Among RA patients, there was a statistically significant increase in the frequency of VAV1 rs2546133 polymorphism in T allele carriers (TT + CT versus CC, odds ratio: 1.69, 95% confidence interval 1.05-2.73, p = 0.035). There was no statistically significant difference in the distribution of the rs2617822 genotypes and alleles between RA patients and the control group. Additionally, patients who carried the VAV1 rs2546133 T and rs2617822 G allele presented an increased frequency of extraarticular manifestations: vasculitis, amyloidosis and Sjogren syndrome. CONCLUSIONS The results suggest an association between VAV1 gene rs2617822 polymorphism and RA.
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Affiliation(s)
- Andrzej Pawlik
- Department of Physiology, Pomeranian Medical University, 70-111 Szczecin, Poland
- Correspondence:
| | - Damian Malinowski
- Department of Experimental and Clinical Pharmacology, Pomeranian Medical University, 70-111 Szczecin, Poland;
| | - Agnieszka Paradowska-Gorycka
- Department of Molecular Biology, National Institute of Geriatrics, Rheumatology and Rehabilitation, 02-637 Warsaw, Poland;
| | - Krzysztof Safranow
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, 70-111 Szczecin, Poland; (K.S.); (V.D.)
| | - Violetta Dziedziejko
- Department of Biochemistry and Medical Chemistry, Pomeranian Medical University, 70-111 Szczecin, Poland; (K.S.); (V.D.)
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2
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Fray MA, Charpentier JC, Sylvain NR, Seminario MC, Bunnell SC. Vav2 lacks Ca 2+ entry-promoting scaffolding functions unique to Vav1 and inhibits T cell activation via Cdc42. J Cell Sci 2020; 133:jcs238337. [PMID: 31974114 PMCID: PMC7075049 DOI: 10.1242/jcs.238337] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/06/2020] [Indexed: 12/16/2022] Open
Abstract
Vav family guanine nucleotide exchange factors (GEFs) are essential regulators of immune function. Despite their structural similarity, Vav1 promotes and Vav2 opposes T cell receptor (TCR)-induced Ca2+ entry. By using a Vav1-deficient Jurkat T cell line, we find that Vav1 facilitates Ca2+ entry via non-catalytic scaffolding functions that are encoded by the catalytic core of Vav1 and flanking linker regions. We implicate, in this scaffolding function, a previously undescribed polybasic motif that is strictly conserved in Vav1 and absent from Vav2 in tetrapods. Conversely, the catalytic activity of Vav2 contributes to the suppression of TCR-mediated Ca2+ entry. By performing an in vivo 'GEF trapping' assay in intact cells, we demonstrate that Cdc42 interacts with the catalytic surface of Vav2 but not Vav1, and that Vav1 discriminates Cdc42 from Rac1 via F56 (W56 in Rac1). Finally, the Cdc42-specific inhibitor ZCL278 and the shRNA-mediated suppression of Cdc42 each prevent the inhibition of TCR-induced Ca2+ entry by Vav2. These findings define stark differences in the functions of Vav1 and Vav2, and provide an explanation for the differential usage of these Vav isoforms by immune subpopulations.
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Affiliation(s)
- Michael A Fray
- Program in Immunology, Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - John C Charpentier
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Nicholas R Sylvain
- Program in Immunology, Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Maria-Cristina Seminario
- Program in Immunology, Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Stephen C Bunnell
- Program in Immunology, Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA
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3
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Rodríguez-Fdez S, Fernández-Nevado L, Lorenzo-Martín LF, Bustelo XR. Lysine Acetylation Reshapes the Downstream Signaling Landscape of Vav1 in Lymphocytes. Cells 2020; 9:cells9030609. [PMID: 32143292 PMCID: PMC7140538 DOI: 10.3390/cells9030609] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/27/2020] [Accepted: 03/02/2020] [Indexed: 12/16/2022] Open
Abstract
Vav1 works both as a catalytic Rho GTPase activator and an adaptor molecule. These functions, which are critical for T cell development and antigenic responses, are tyrosine phosphorylation-dependent. However, it is not known whether other posttranslational modifications can contribute to the regulation of the biological activity of this protein. Here, we show that Vav1 becomes acetylated on lysine residues in a stimulation- and SH2 domain-dependent manner. Using a collection of both acetylation- and deacetylation-mimicking mutants, we show that the acetylation of four lysine residues (Lys222, Lys252, Lys587, and Lys716) leads to the downmodulation of the adaptor function of Vav1 that triggers the stimulation of the nuclear factor of activated T cells (NFAT). These sites belong to two functional subclasses according to mechanistic criteria. We have also unveiled additional acetylation sites potentially involved in either the stimulation (Lys782) or the downmodulation (Lys335, Lys374) of specific Vav1-dependent downstream responses. Collectively, these results indicate that Nε-lysine acetylation can play variegated roles in the regulation of Vav1 signaling. Unlike the case of the tyrosine phosphorylation step, this new regulatory layer is not conserved in other Vav family paralogs.
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Affiliation(s)
- Sonia Rodríguez-Fdez
- Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (L.F.-N.); (L.F.L.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC-University of Salamanca, 37007 Salamanca, Spain
| | - Lucía Fernández-Nevado
- Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (L.F.-N.); (L.F.L.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
| | - L. Francisco Lorenzo-Martín
- Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (L.F.-N.); (L.F.L.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC-University of Salamanca, 37007 Salamanca, Spain
| | - Xosé R. Bustelo
- Centro de Investigación del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (L.F.-N.); (L.F.L.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC-University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC-University of Salamanca, 37007 Salamanca, Spain
- Correspondence: ; Tel.: +34-663194634
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4
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Rodríguez-Fdez S, Citterio C, Lorenzo-Martín LF, Baltanás-Copado J, Llorente-González C, Corbalán-García S, Vicente-Manzanares M, Bustelo XR. Phosphatidylinositol Monophosphates Regulate Optimal Vav1 Signaling Output. Cells 2019; 8:cells8121649. [PMID: 31888228 PMCID: PMC6952945 DOI: 10.3390/cells8121649] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/12/2019] [Accepted: 12/13/2019] [Indexed: 01/13/2023] Open
Abstract
Phosphatidylinositol–5 phosphate (PI5P) and other mono-phosphoinositides (mono-PIs) play second messenger roles in both physiological and pathological conditions. Despite this, their intracellular targets and mechanisms of action remain poorly characterized. Here, we show that Vav1, a protein that exhibits both Rac1 GDP/GTP exchange and adaptor activities, is positively modulated by PI5P and, possibly, other mono-PIs. Unlike other phospholipid–protein complexes, the affinity and specificity of the Vav1–lipid interaction entail a new structural solution that involves the synergistic action of the Vav1 C1 domain and an adjacent polybasic tail. This new regulatory layer, which is not conserved in the Vav family paralogs, favors the engagement of optimal Vav1 signaling outputs in lymphocytes.
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Affiliation(s)
- Sonia Rodríguez-Fdez
- Centro de Investigación del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (C.C.); (L.F.L.-M.); (C.L.-G.); (M.V.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC–University of Salamanca, 37007 Salamanca, Spain
| | - Carmen Citterio
- Centro de Investigación del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (C.C.); (L.F.L.-M.); (C.L.-G.); (M.V.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain
| | - L. Francisco Lorenzo-Martín
- Centro de Investigación del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (C.C.); (L.F.L.-M.); (C.L.-G.); (M.V.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC–University of Salamanca, 37007 Salamanca, Spain
| | - Jesús Baltanás-Copado
- Department of Biochemistry and Molecular Biology, University of Murcia, 30100 Murcia, Spain; (J.B.-C.); (S.C.-G.)
- Biomedical Research Institute of Murcia, University of Murcia, 30100 Murcia, Spain
| | - Clara Llorente-González
- Centro de Investigación del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (C.C.); (L.F.L.-M.); (C.L.-G.); (M.V.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain
| | - Senena Corbalán-García
- Department of Biochemistry and Molecular Biology, University of Murcia, 30100 Murcia, Spain; (J.B.-C.); (S.C.-G.)
- Biomedical Research Institute of Murcia, University of Murcia, 30100 Murcia, Spain
| | - Miguel Vicente-Manzanares
- Centro de Investigación del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (C.C.); (L.F.L.-M.); (C.L.-G.); (M.V.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain
| | - Xosé R. Bustelo
- Centro de Investigación del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain; (S.R.-F.); (C.C.); (L.F.L.-M.); (C.L.-G.); (M.V.-M.)
- Instituto de Biología Molecular y Celular del Cáncer, CSIC–University of Salamanca, 37007 Salamanca, Spain
- Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), CSIC–University of Salamanca, 37007 Salamanca, Spain
- Correspondence:
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5
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The Vav GEF Family: An Evolutionary and Functional Perspective. Cells 2019; 8:cells8050465. [PMID: 31100928 PMCID: PMC6562523 DOI: 10.3390/cells8050465] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 05/10/2019] [Accepted: 05/15/2019] [Indexed: 02/07/2023] Open
Abstract
Vav proteins play roles as guanosine nucleotide exchange factors for Rho GTPases and signaling adaptors downstream of protein tyrosine kinases. The recent sequencing of the genomes of many species has revealed that this protein family originated in choanozoans, a group of unicellular organisms from which animal metazoans are believed to have originated from. Since then, the Vav family underwent expansions and reductions in its members during the evolutionary transitions that originated the agnates, chondrichthyes, some teleost fish, and some neoaves. Exotic members of the family harboring atypical structural domains can be also found in some invertebrate species. In this review, we will provide a phylogenetic perspective of the evolution of the Vav family. We will also pay attention to the structure, signaling properties, regulatory layers, and functions of Vav proteins in both invertebrate and vertebrate species.
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6
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Wang R, Wang J, Zhang N, Wan Y, Liu Y, Zhang L, Pan S, Zhang C, Zhang H, Cao Y. The interaction between Vav1 and EBNA1 promotes survival of Burkitt's lymphoma cells by down-regulating the expression of Bim. Biochem Biophys Res Commun 2019; 511:787-793. [PMID: 30833082 DOI: 10.1016/j.bbrc.2019.02.108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 02/16/2019] [Accepted: 02/20/2019] [Indexed: 01/11/2023]
Abstract
Vav1 is a guanine nucleotide exchange factor (GEF) predominantly expressed in hematopoietic cells, and functions in the development and antigen-stimulated response of lymphocytes. Burkitt's lymphoma (BL) is characterized as transformed B cell lymphoma, and is highly associated with Epstein-Barr virus (EBV). EBV nuclear antigen 1 (EBNA1) is the only viral protein expressed across all three types of latency and essential for the persistence of EBV genome. It is not clear yet how EBNA1 contributes to the growth advantage of latently infected cells such as in EBV+ lymphoma B cells. Here, we reported that Vav1 interacts with EBNA1 via its C-terminal SH3 domain. This interaction suppresses the expression of a pro-apoptotic Bcl-2 family member, Bim, resulting in the resistance of the BL cells to apoptotic inductions. Our data uncovered Vav1 as a novel target for EBNA1, and suggested a pro-survival role of Vav1 in the pathogenesis of EBV associated BLs.
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Affiliation(s)
- Ruikun Wang
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Jiyan Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Nianchao Zhang
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yajuan Wan
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yaohui Liu
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Liming Zhang
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Shuang Pan
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Cuizhu Zhang
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Hongkai Zhang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China.
| | - Youjia Cao
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China; Tianjin Key Laboratory of Protein Sciences, College of Life Sciences, Nankai University, Tianjin, China.
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7
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Barreira M, Rodríguez-Fdez S, Bustelo XR. New insights into the Vav1 activation cycle in lymphocytes. Cell Signal 2018; 45:132-144. [PMID: 29410283 PMCID: PMC7615736 DOI: 10.1016/j.cellsig.2018.01.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 01/28/2018] [Accepted: 01/30/2018] [Indexed: 10/18/2022]
Abstract
Vav1 is a hematopoietic-specific Rho GDP/GTP exchange factor and signaling adaptor. Although these activities are known to be stimulated by direct Vav1 phosphorylation, little information still exists regarding the regulatory layers that influence the overall Vav1 activation cycle. Using a collection of cell models and activation-mimetic Vav1 mutants, we show here that the dephosphorylated state of Vav1 in nonstimulated T cells requires the presence of a noncatalytic, phospholipase Cγ1-Slp76-mediated inhibitory pathway. Upon T cell stimulation, Vav1 becomes rapidly phosphorylated via the engagement of Lck and, to a much lesser extent, other Src family kinases and Zap70. In this process, Lck, Zap70 and the adaptor protein Lat contribute differently to the dynamics and amplitude of the Vav1 phosphorylated pool. Consistent with a multiphosphosite activation mechanism, the optimal stimulation of Vav1 can only be recapitulated by the combination of several activation-mimetic phosphosite mutants. The analysis of these mutants has also unveiled the presence of different Vav1 signaling competent states that are influenced by phosphosites present in the N- and C-terminal domains of the protein.
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Affiliation(s)
- María Barreira
- Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain; Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain
| | - Sonia Rodríguez-Fdez
- Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain; Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain
| | - Xosé R Bustelo
- Centro de Investigación del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain; Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain; Centro de Investigación Biomédica en Red de Cáncer (CIBERONC), Consejo Superior de Investigaciones Científicas (CSIC), University of Salamanca, 37007 Salamanca, Spain.
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8
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The Calcium-Dependent Switch Helix of L-Plastin Regulates Actin Bundling. Sci Rep 2017; 7:40662. [PMID: 28145401 PMCID: PMC5286426 DOI: 10.1038/srep40662] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/09/2016] [Indexed: 01/14/2023] Open
Abstract
L-plastin is a calcium-regulated actin-bundling protein that is expressed in cells of hematopoietic origin and in most metastatic cancer cells. These cell types are mobile and require the constant remodeling of their actin cytoskeleton, where L-plastin bundles filamentous actin. The calcium-dependent regulation of the actin-bundling activity of L-plastin is not well understood. We have used NMR spectroscopy to determine the solution structure of the EF-hand calcium-sensor headpiece domain. Unexpectedly, this domain does not bind directly to the four CH-domains of L-plastin. A novel switch helix is present immediately after the calcium-binding region and it binds tightly to the EF-hand motifs in the presence of calcium. We demonstrate that this switch helix plays a major role during actin-bundling. Moreover a peptide that competitively inhibits the association between the EF-hand motifs and the switch helix was shown to deregulate the actin-bundling activity of L-plastin. Overall, these findings may help to develop new drugs that target the L-plastin headpiece and interfere in the metastatic activity of cancer cells.
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Activating mutations and translocations in the guanine exchange factor VAV1 in peripheral T-cell lymphomas. Proc Natl Acad Sci U S A 2017; 114:764-769. [PMID: 28062691 DOI: 10.1073/pnas.1608839114] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Peripheral T-cell lymphomas (PTCLs) are a heterogeneous group of non-Hodgkin lymphomas frequently associated with poor prognosis and for which genetic mechanisms of transformation remain incompletely understood. Using RNA sequencing and targeted sequencing, here we identify a recurrent in-frame deletion (VAV1 Δ778-786) generated by a focal deletion-driven alternative splicing mechanism as well as novel VAV1 gene fusions (VAV1-THAP4, VAV1-MYO1F, and VAV1-S100A7) in PTCL. Mechanistically these genetic lesions result in increased activation of VAV1 catalytic-dependent (MAPK, JNK) and non-catalytic-dependent (nuclear factor of activated T cells, NFAT) VAV1 effector pathways. These results support a driver oncogenic role for VAV1 signaling in the pathogenesis of PTCL.
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Liu J, Kurella VB, LeCour L, Vanagunas T, Worthylake DK. The IQGAP1 N-Terminus Forms Dimers, and the Dimer Interface Is Required for Binding F-Actin and Calcium-Bound Calmodulin. Biochemistry 2016; 55:6433-6444. [PMID: 27798963 DOI: 10.1021/acs.biochem.6b00745] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
IQGAP1 is a multidomain scaffold protein involved in many cellular processes. We have determined the crystal structure of an N-terminal fragment spanning residues 1-191 (CHDF hereafter) that contains the entire calponin homology domain. The structure of the CHDF is very similar to those of other type 3 calponin homology domains like those from calponin, Vav, and the yeast IQGAP1 ortholog Rng2. However, in the crystal, two CHDF molecules form a "head-to-head" or parallel dimer through mostly hydrophobic interactions. Binding experiments indicate that the CHDF binds to both F-actin and Ca2+/calmodulin, but binding is mutually exclusive. On the basis of the structure, two dimer interface substitutions were introduced. While CHDFL157D disrupts the dimer in gel filtration experiments, oxidized CHDFK161C stabilizes the dimer. These results imply that the CHDF forms the same dimer in solution that is seen in the crystal structure. The disulfide-stabilized dimer displays a reduced level of F-actin binding in sedimentation assays and shows no binding to Ca2+/calmodulin in isothermal titration calorimetry (ITC) experiments, indicating that interface residues are utilized for both binding events. The Calmodulin Target Database predicts that residues 93KK94 are important for CaM binding, and indeed, the 93EE94 double mutation displays a reduced level of binding to Ca2+/calmodulin in ITC experiments. Our results indicate that the CHDF dimer interface is used for both F-actin and Ca2+/calmodulin binding, and the 93KK94 pair, near the interface, is also used for Ca2+/calmodulin binding. These results are also consistent with full-length IQGAP1 forming a parallel homodimer.
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Affiliation(s)
- Jing Liu
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - Vinodh B Kurella
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - Louis LeCour
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - Tomas Vanagunas
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - David K Worthylake
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
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Vav1: A Dr. Jekyll and Mr. Hyde protein--good for the hematopoietic system, bad for cancer. Oncotarget 2016; 6:28731-42. [PMID: 26353933 PMCID: PMC4745688 DOI: 10.18632/oncotarget.5086] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 08/07/2015] [Indexed: 01/10/2023] Open
Abstract
Many deregulated signal transducer proteins are involved in various cancers at numerous stages of tumor development. One of these, Vav1, is normally expressed exclusively in the hematopoietic system, where it functions as a specific GDP/GTP nucleotide exchange factor (GEF), strictly regulated by tyrosine phosphorylation. Vav was first identified in an NIH3T3 screen for oncogenes. Although the oncogenic form of Vav1 identified in the screen has not been detected in clinical human tumors, its wild-type form has recently been implicated in mammalian malignancies, including neuroblastoma, melanoma, pancreatic, lung and breast cancers, and B-cell chronic lymphocytic leukemia. In addition, it was recently identified as a mutated gene in human cancers of various origins. However, the activity and contribution to cancer of these Vav1 mutants is still unclear. This review addresses the physiological function of wild-type Vav1 and its activity as an oncogene in human cancer. It also discusses the novel mutations identified in Vav1 in various cancers and their potential contribution to cancer development as oncogenes or tumor suppressor genes.
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12
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Abstract
The Vav family is a group of tyrosine phosphorylation-regulated signal transduction molecules hierarchically located downstream of protein tyrosine kinases. The main function of these proteins is to work as guanosine nucleotide exchange factors (GEFs) for members of the Rho GTPase family. In addition, they can exhibit a variety of catalysis-independent roles in specific signaling contexts. Vav proteins play essential signaling roles for both the development and/or effector functions of a large variety of cell lineages, including those belonging to the immune, nervous, and cardiovascular systems. They also contribute to pathological states such as cancer, immune-related dysfunctions, and atherosclerosis. Here, I will provide an integrated view about the evolution, regulation, and effector properties of these signaling molecules. In addition, I will discuss the pros and cons for their potential consideration as therapeutic targets.
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Key Words
- Ac, acidic
- Ahr, aryl hydrocarbon receptor
- CH, calponin homology
- CSH3, most C-terminal SH3 domain of Vav proteins
- DAG, diacylglycerol
- DH, Dbl-homology domain
- Dbl-homology
- GDP/GTP exchange factors
- GEF, guanosine nucleotide exchange factor
- HIV, human immunodeficiency virus
- IP3, inositoltriphosphate
- NFAT, nuclear factor of activated T-cells
- NSH3, most N-terminal SH3 domain of Vav proteins
- PH, plekstrin-homology domain
- PI3K, phosphatidylinositol-3 kinase
- PIP3, phosphatidylinositol (3,4,5)-triphosphate
- PKC, protein kinase C
- PKD, protein kinase D
- PLC-g, phospholipase C-g
- PRR, proline-rich region
- PTK, protein tyrosine kinase
- Phox, phagocyte oxidase
- Rho GTPases
- SH2, Src homology 2
- SH3, Src homology 3
- SNP, single nucleotide polymorphism
- TCR, T-cell receptor
- Vav
- ZF, zinc finger region
- cGMP, cyclic guanosine monophosphate
- cancer
- cardiovascular biology
- disease
- immunology
- nervous system
- signaling
- therapies
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Affiliation(s)
- Xosé R Bustelo
- a Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer ; Consejo Superior de Investigaciones Científicas (CSIC) and University of Salamanca ; Campus Unamuno; Salamanca , Spain
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13
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Estrogen induces Vav1 expression in human breast cancer cells. PLoS One 2014; 9:e99052. [PMID: 24905577 PMCID: PMC4048212 DOI: 10.1371/journal.pone.0099052] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Accepted: 05/09/2014] [Indexed: 12/21/2022] Open
Abstract
Vav1, a guanine nucleotide exchange factor (GEF) for Rho family GTPases, is a hematopoietic protein involved in a variety of cellular events. In recent years, aberrant expression of Vav1 has been reported in non-hematopoietic cancers including human breast cancer. It remains to be answered how Vav1 is expressed and what Vav1 does in its non-resident tissues. In this study, we aimed to explore the mechanism for Vav1 expression in breast cancer cells in correlation with estrogen-ER pathway. We not only verified the ectopic expression of Vav1 in human breast cancer cell lines, but also observed that Vav1 expression was induced by 17β-estradiol (E2), a typical estrogen receptor (ER) ligand, in ER-positive cell lines. On the other hand, Tamoxifen, a selective estrogen receptor modulator (SERM), and ICI 182,780, an ER antagonist, suppressed the expression of Vav1. The estrogen receptor modulating Vav1 expression was identified to be α form, not β. Furthermore, treatment of E2 increased the transcription of vav1 gene by enhancing the promoter activity, though there was no recognizable estrogen response element (ERE). Nevertheless, two regions at the vav1 gene promoter were defined to be responsible for E2-induced activation of vav1 promoter. Chromatin immunoprecipitation (ChIP) and co-immunoprecipitation (Co-IP) analyses suggested that ERα might access to the vav1 promoter via interacting with transcription factors, c-Myb and ELF-1. Consequently, the enhanced expression of Vav1 led to the elevation of Cyclin D1 and the progression of cell cycle. The present study implies that estrogen-ER modulates the transcription and expression of Vav1, which may contribute to the proliferation of cancerous cells.
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14
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Babich A, Burkhardt JK. Coordinate control of cytoskeletal remodeling and calcium mobilization during T-cell activation. Immunol Rev 2014; 256:80-94. [PMID: 24117814 DOI: 10.1111/imr.12123] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ca(2+) mobilization and cytoskeletal reorganization are key hallmarks of T-cell activation, and their interdependence has long been recognized. Recent advances in the field have elucidated the molecular pathways that underlie these events and have revealed several points of intersection. Ca(2+) signaling can be divided into two phases: initial events leading to release of Ca(2+) from endoplasmic reticulum stores, and a second phase involving STIM 1 (stromal interaction molecule 1) clustering and CRAC (calcium release activated calcium) channel activation. Cytoskeletal dynamics promote both phases. During the first phase, the actin cytoskeleton promotes mechanotransduction and serves as a dynamic scaffold for microcluster assembly. Proteins that drive actin polymerization such as WASp (Wiskott-Aldrich syndrome protein) and HS1 (hematopoietic lineage cell-specific protein 1) promote signaling through PLCγ1 (phospholipase Cγ1) and release of Ca(2+) from endoplasmic reticulum stores. During the second phase, the WAVE (WASP-family verprolin homologous protein) complex and the microtubule cytoskeleton promote STIM 1 clustering at sites of plasma membrane apposition, opening Orai channels. In addition, gross cell shape changes and organelle movements buffer local Ca(2+) levels, leading to sustained Ca(2+) mobilization. Conversely, elevated intracellular Ca(2+) activates cytoskeletal remodeling. This can occur indirectly, via calpain activity, and directly, via Ca(2+) -dependent cytoskeletal regulatory proteins such as myosin II and L-plastin. While it is true that the cytoskeleton regulates Ca(2+) responses and vice versa, interdependence between Ca(2+) and the cytoskeleton also encompasses signaling events that occur in parallel, downstream of shared intermediates. Inositol cleavage by PLCγ1 simultaneously triggers both endoplasmic reticulum store release and diacylglycerol-dependent microtubule organizing center reorientation, while depleting the pool of phosphatidylinositol-4,5-bisphosphate, an activator of multiple actin-regulatory proteins. The close interdependence of Ca(2+) signaling and cytoskeletal dynamics in T cells provides positive feedback mechanisms for T-cell activation and allows for finely tuned responses to extracellular cues.
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Affiliation(s)
- Alexander Babich
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia and Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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15
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Barreira M, Fabbiano S, Couceiro JR, Torreira E, Martínez-Torrecuadrada JL, Montoya G, Llorca O, Bustelo XR. The C-terminal SH3 domain contributes to the intramolecular inhibition of Vav family proteins. Sci Signal 2014; 7:ra35. [PMID: 24736456 DOI: 10.1126/scisignal.2004993] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Vav proteins are phosphorylation-dependent guanine nucleotide exchange factors (GEFs) that catalyze the activation of members of the Rho family of guanosine triphosphatases (GTPases). The current regulatory model holds that the nonphosphorylated, catalytically inactive state of these GEFs is maintained by intramolecular interactions among the amino-terminal domains and the central catalytic core, which block the binding of Vav proteins to GTPases. We showed that this autoinhibition is mechanistically more complex, also involving the bivalent association of the carboxyl-terminal Src homology 3 (SH3) region of Vav with its catalytic and pleckstrin homology (PH) domains. Such interactions occurred through proline-rich region-independent mechanisms. Full release from this double-locked state required synergistic weakening effects from multiple phosphorylated tyrosine residues, thus providing an optimized system to generate gradients of Vav GEF activity depending on upstream signaling inputs. This mechanism is shared by mammalian and Drosophila melanogaster Vav proteins, suggesting that it may be a common regulatory feature for this protein family.
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Affiliation(s)
- María Barreira
- 1Centro de Investigación del Cáncer, Campus Unamuno, E37007 Salamanca, Spain
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16
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Li SY, Du MJ, Wan YJ, Lan B, Liu YH, Yang Y, Zhang CZ, Cao Y. The N-terminal 20-amino acid region of guanine nucleotide exchange factor Vav1 plays a distinguished role in T cell receptor-mediated calcium signaling. J Biol Chem 2012; 288:3777-85. [PMID: 23271736 DOI: 10.1074/jbc.m112.426221] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Vav1 is a guanine nucleotide exchange factor (GEF) specifically expressed in hematopoietic cells. It consists of multiple structural domains and plays important roles in T cell activation. The other highly conserved isoforms of Vav family, Vav2 and Vav3, are ubiquitously expressed in human tissues including lymphocytes. All three Vav proteins activate Rho family small GTPases, which are involved in a variety of biological processes during T cell activation. Intensive studies have demonstrated that Vav1 is indispensable for T cell receptor (TCR)-mediated signal transduction, whereas Vav2 and Vav3 function as GEFs that overlap with Vav1 on TCR-induced cytoskeleton reorganization. T cells lacking Vav1 exhibited severe defect in TCR-mediated calcium elevation, indicating that the co-existing Vav2 and Vav3 did not compensate Vav1 in calcium signaling. What is the functional particularity of Vav1 in lymphocytes? In this study, we identified the N-terminal 20 amino acids of Vav1 in the calponin homology (CH) domain to be essential for its interaction with calmodulin (CaM) that leads to TCR-induced calcium mobilization. Substitution of the 1-20 amino acids of Vav1 with those of Vav2 or Vav3 abolished the association with CaM, and the N-terminal mutations of Vav1 failed to potentiate normal TCR-induced calcium mobilization, that in turn, suspended nuclear factor of activated T cells (NFAT) activation and IL-2 production. This study highlights the importance of the N-terminal 20 aa of Vav1 for CaM binding, and provides new insights into the distinguished and irreplaceable role of Vav1 in T cell activation and signal transduction.
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Affiliation(s)
- Shi-Yang Li
- Key Laboratory of Microbial Functional Genomics of the Ministry of Education, Medicinal Chemical Biology College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, Peoples Republic of China
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17
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Andrews WJ, Bradley CA, Hamilton E, Daly C, Mallon T, Timson DJ. A calcium-dependent interaction between calmodulin and the calponin homology domain of human IQGAP1. Mol Cell Biochem 2012; 371:217-23. [PMID: 22944912 DOI: 10.1007/s11010-012-1438-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/25/2012] [Indexed: 01/01/2023]
Abstract
IQGAPs are cytoskeletal scaffolding proteins which collect information from a variety of signalling pathways and pass it on to the microfilaments and microtubules. There is a well-characterised interaction between IQGAP and calmodulin through a series of IQ-motifs towards the middle of the primary sequence. However, it has been shown previously that the calponin homology domain (CHD), located at the N-terminus of the protein, can also interact weakly with calmodulin. Using a recombinant fragment of human IQGAP1 which encompasses the CHD, we have demonstrated that the CHD undergoes a calcium ion-dependent interaction with calmodulin. The CHD can also displace the hydrophobic fluorescent probe 1-anilinonaphthalene-8-sulphonate from calcium-calmodulin, suggesting that the interaction involves non-polar residues on the surface of calmodulin. Molecular modelling identified a possible site on the CHD for calmodulin interaction. The physiological significance of this interaction remains to be discovered.
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Affiliation(s)
- William J Andrews
- School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
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18
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Huang Y, Li W, Huang L, Hu Y, Chen W, Wang X, Sun J, Liang C, Wu Z, Li X, Xu J, Yu X. Identification and characterization of myophilin-like protein: a life stage and tissue-specific antigen of Clonorchis sinensis. Parasitol Res 2012; 111:1143-50. [PMID: 22752695 DOI: 10.1007/s00436-012-2946-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 04/23/2012] [Indexed: 12/24/2022]
Abstract
Clonorchiasis, caused by Clonorchis sinensis infection, has been an important public health problem in China. More messages about biology and pathogenicity of C. sinensis will be better for development of new strategies for clonorchiasis control. In the current study, using data from the published genomic and cDNA sequences for C. sinensis, we identify a gene encoding a myophilin-like protein (Cs myophilin-like). The cDNA sequence is 573 bp in length which encoded a protein of 190 amino acids. DNA sequence of Cs myophilin-like consists of four extrons and three introns. By mapping the draft genome of C. sinensis, single copy of myophilin-like gene is annotated. Bioinformatic analysis shows Cs myophilin-like comprises a calponin homology domain and three actin binding surfaces. It expresses at the life stage of adult worm and metacercaria but not in eggs. It intensively distributes in muscular locations such as oral sucker and pharynx of adult worm and sucker of metacercaria. The transcript level of Cs myophilin-like in oral sucker and pharynx is significantly higher than that in the rest of adult worm. Moreover, recombinant Cs myophilin-like is obtained and of antigenicity and immunoreactivity. It can be probed by sera from patients infected with trematode or cestode. Our data suggests that Cs myophilin-like may be involved in the host tissue invasion besides regulating the contraction of smooth muscle and movement of worm body. Taken together, the stable and soluble expression in Escherichia coli and immunogenicity of recombinant Cs myophilin-like proteins suggest that Cs myophilin-like may be a potential candidate for vaccine and drug target for clonorchiasis.
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Affiliation(s)
- Yan Huang
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, 510080, China
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19
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Knyazhitsky M, Moas E, Shaginov E, Luria A, Braiman A. Vav1 oncogenic mutation inhibits T cell receptor-induced calcium mobilization through inhibition of phospholipase Cγ1 activation. J Biol Chem 2012; 287:19725-35. [PMID: 22474331 DOI: 10.1074/jbc.m111.309799] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Robust elevation of the cytosolic calcium concentration is a crucial early step for T cell activation triggered by the T cell antigen receptor. Vav1 is a proto-oncogene expressed in hematopoietic cells that is indispensable for transducing the calcium-mobilizing signal. Following T cell receptor stimulation, Vav1 facilitates formation of signaling microclusters through multiple interactions with other proteins participating in the signaling cascade. Truncation of the N terminus of Vav1 produces its oncogenic version, which is unable to support normal calcium flux following T cell activation. We show here that truncation of the N-terminal region of Vav1 alters the fine structure of protein complexes in the signaling clusters, affecting the interaction of Vav1 with phospholipase Cγ1 (PLCγ1). This alteration is accompanied by a decrease in PLCγ1 phosphorylation and inhibition of inositol 1,4,5-trisphosphate production. We suggest that the structural integrity of the N-terminal region of Vav1 is important for the proper formation of the Vav1-associated signaling complexes. The oncogenic truncation of this region elicits conformational changes that interfere with the Vav1-mediated activation of PLCγ1 and that inhibit calcium mobilization.
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Affiliation(s)
- Mira Knyazhitsky
- Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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20
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Rahaman SO, Zhou G, Silverstein RL. Vav protein guanine nucleotide exchange factor regulates CD36 protein-mediated macrophage foam cell formation via calcium and dynamin-dependent processes. J Biol Chem 2011; 286:36011-36019. [PMID: 21865158 DOI: 10.1074/jbc.m111.265082] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Atherosclerosis, a chronic inflammatory disease, results in part from the accumulation of modified lipoproteins in the arterial wall and formation of lipid-laden macrophages, known as "foam cells." Recently, we reported that CD36, a scavenger receptor, contributes to activation of Vav-family guanine nucleotide exchange factors by oxidatively modified LDL in macrophages. We also discovered that CD36-dependent uptake of oxidized LDL (oxLDL) in vitro and foam cell formation in vitro and in vivo was significantly reduced in macrophages deficient of Vav proteins. The goal of the present study was to identify the mechanisms by which Vav proteins regulate CD36-dependent foam cell formation. We now show that a Vav-dynamin signaling axis plays a critical role in generating calcium signals in mouse macrophages exposed to CD36-specific oxidized phospholipid ligands. Chelation of intracellular Ca(2+) or inhibition of phospholipase C-γ (PLC-γ) inhibited Vav activation (85 and 70%, respectively, compared with vehicle control) and reduced foam cell formation (approximately 75%). Knockdown of expression by siRNA or inhibition of GTPase activity of dynamin 2, a Vav-interacting protein involved in endocytic vesicle fission, significantly blocked oxLDL uptake and inhibited foam cell formation. Immunofluorescence microscopy studies showed that Vav1 and dynamin 2 colocalized with internalized oxLDL in macrophages and that activation and mobilization of dynamin 2 by oxLDL was impaired in vav null cells. These studies identified previously unknown components of the CD36 signaling pathway, demonstrating that Vav proteins regulate oxLDL uptake and foam cell formation via calcium- and dynamin 2-dependent processes and thus represent novel therapeutic targets for atherosclerosis.
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Affiliation(s)
- S Ohidar Rahaman
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195.
| | - Gang Zhou
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Roy L Silverstein
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine, Cleveland, Ohio 44195.
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21
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Abstract
Since their identification over 15 years ago, the IQGAP (IQ-motif-containing GTPase-activating protein) family of proteins have been implicated in a wide range of cellular processes, including cytoskeletal reorganization, cell-cell adhesion, cytokinesis and apoptosis. These processes rely on protein-protein interactions, and understanding these (and how they influence one another) is critical in determining how the IQGAPs function. A key group of interactions is with calmodulin and the structurally related proteins myosin essential light chain and S100B. These interactions occur primarily through a series of IQ motifs, which are α-helical segments of the protein located towards the middle of the primary sequence. The three human IQGAP isoforms (IQGAP1, IQGAP2 and IQGAP3) all have four IQ motifs. However, these have different affinities for calmodulin, myosin light chain and S100B. Whereas all four IQ motifs of IQGAP1 interact with calmodulin in the presence of calcium, only the last two do so in the absence of calcium. IQ1 (the first IQ motif) interacts with the myosin essential light chain Mlc1sa and the first two undergo a calcium-dependent interaction with S100B. The significance of the interaction between Mlc1sa and IQGAP1 in mammals is unknown. However, a similar interaction involving the Saccharomyces cerevisiae IQGAP-like protein Iqg1p is involved in cytokinesis, leading to speculation that there may be a similar role in mammals.
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22
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Sylvain NR, Nguyen K, Bunnell SC. Vav1-mediated scaffolding interactions stabilize SLP-76 microclusters and contribute to antigen-dependent T cell responses. Sci Signal 2011; 4:ra14. [PMID: 21386095 DOI: 10.1126/scisignal.2001178] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The guanine nucleotide exchange factor (GEF) Vav1 synergizes with the adaptor protein SLP-76 (Src homology 2 domain--containing leukocyte phosphoprotein of 76 kD) to support T cell development and activation. In response to ligation of the T cell receptor (TCR), SLP-76 is assembled into microclusters that provide an essential platform for the signaling events that drive T cell activation. We found that Vav1 selectively entered SLP-76 microclusters, rather than TCR microclusters, influencing their stability and function. The carboxyl terminus of Vav1, which consists of Src homology domains, was both necessary and sufficient for the entry of Vav1 into SLP-76 microclusters; however, this fragment of Vav1 was insufficient to stabilize the microclusters, and it potently suppressed T cell activation. This indicated that the amino terminus of Vav1, which has the GEF domain, also contributed to the integrity of SLP-76 microclusters and thereby to T cell activation. These microcluster-stabilizing functions were independent of the GEF activity in the amino terminus of Vav1 and were unaffected if the GEF function of Vav1 was either inactivated or constitutively activated by mutation. In contrast, Vav1 deletion mutants lacking either the calponin homology domain or the catalytic core of the GEF exhibited mild scaffolding defects, but they differentially affected TCR-dependent calcium ion (Ca²+) responses. We conclude that multiple GEF-independent scaffolding functions distributed throughout the amino terminus of Vav1 contribute to the activation of T cells by acting synergistically to increase the stability and function of SLP-76 microclusters.
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Affiliation(s)
- Nicholas R Sylvain
- Program in Immunology, Sackler School of Graduate Biomedical Sciences, Tufts University School of Medicine, Boston, MA 02111, USA
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23
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Yin J, Wan YJ, Li SY, Du MJ, Zhang CZ, Zhou XL, Cao YJ. The distinct role of guanine nucleotide exchange factor Vav1 in Bcl-2 transcription and apoptosis inhibition in Jurkat leukemia T cells. Acta Pharmacol Sin 2011; 32:99-107. [PMID: 21151158 PMCID: PMC4003318 DOI: 10.1038/aps.2010.185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 09/28/2010] [Indexed: 11/09/2022] Open
Abstract
AIM To investigate a novel function of proto-oncogene Vav1 in the apoptosis of human leukemia Jurkat cells. METHODS Jurkat cells, Jurkat-derived vav1-null cells (J.Vav1) and Vav1-reconstituted J.WT cells were treated with a Fas agonist antibody, IgM clone CH11. Apoptosis was determined using propidium iodide (PI) staining, Annexin-V staining, DNA fragmentation, cleavage of caspase 3/caspase 8, and poly (ADP-ribose) polymerase (PARP). Mitochondria transmembrane potential (ΔΨ(m)) was measured using DiOC(6)(3) staining. Transcription and expression of the Bcl-2 family of proteins were evaluated using semi-quantitative RT-PCR and Western blot, respectively. Bcl-2 promoter activity was analyzed using luciferase reporter assays. RESULTS Cells lacking Vav1 were more sensitive to Fas-mediated apoptosis than Jurkat and J.WT cells. J.Vav1 cells lost mitochondria transmembrane potential (ΔΨ(m)) more rapidly upon Fas induction. These phenotypes could be rescued by re-expression of Vav1 in J.Vav1 cells. The expression of Vav1 increased the transcription of pro-survival Bcl-2. The guanine nucleotide exchange activity of Vav1 was required for enhancing Bcl-2 promoter activity, and the Vav1 downstream substrate, small GTPase Rac2, was likely involved in the control of Bcl-2 expression. CONCLUSION Vav1 protects Jurkat cells from Fas-mediated apoptosis by promoting Bcl-2 transcription through its GEF activity.
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Affiliation(s)
- Jie Yin
- Tianjin Key Laboratory of Protein Sciences, Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ya-juan Wan
- Tianjin Key Laboratory of Protein Sciences, Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Shi-yang Li
- Tianjin Key Laboratory of Protein Sciences, Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Ming-juan Du
- Tianjin Key Laboratory of Protein Sciences, Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Cui-zhu Zhang
- Tianjin Key Laboratory of Protein Sciences, Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - Xing-long Zhou
- Tianjin Key Laboratory of Protein Sciences, Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
| | - You-jia Cao
- Tianjin Key Laboratory of Protein Sciences, Department of Biochemistry and Molecular Biology, College of Life Sciences, Nankai University, Tianjin 300071, China
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Vav1 couples the T cell receptor to cAMP response element activation via a PKC-dependent pathway. Cell Signal 2010; 22:944-54. [PMID: 20138987 DOI: 10.1016/j.cellsig.2010.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 01/25/2010] [Accepted: 02/01/2010] [Indexed: 12/21/2022]
Abstract
The transcription factor cAMP-responsive element binding protein (CREB) is a regulator of the expression of several genes important for lymphocyte activation and proliferation. However, the proximal signaling events leading to activation of CREB in T cells upon antigen receptor stimulation remain unknown. Here we identify a role for Vav1 in the activation of the cAMP response element (CRE), the binding site for CREB. T cell receptor (TCR)/CD28 - induced costimulation of Jurkat T cells expressing Vav1 but not a GEF-deficient mutant showed increased CRE activation (7.2+/-2.4 fold over control), whereas Vav1 downregulation by siRNA reduced activation of CRE by 2.6+/-1.3 fold. Inhibition of PKC and MEK but not p38 could reduce Vav1-mediated CRE activation, suggesting that Vav1 transmits TCR and CD28 signals to activation of CRE via PKC and ERK signaling pathways. As a consequence, downregulation of Vav1 impaired the expression of several CRE-containing genes like cyclin D1, INFgamma and IL-2, whereas overexpression of Vav1 enhanced CRE-dependent gene expression. Furthermore, cAMP-induced CRE-dependent transcription and gene expression was also modulated by Vav1, but did not require activation of PKC and the GEF function of Vav1. Our data provide insights into the signal transduction events regulating CRE-mediated gene expression in T cells, which affects T cell development, proliferation and activation. We identify Vav1 as an essential component of TCR-induced CRE activation and gene expression, which underlines the central role for Vav1 as key player for TCR signal transduction and gene expression.
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25
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Katzav S. Vav1: A hematopoietic signal transduction molecule involved in human malignancies. Int J Biochem Cell Biol 2009; 41:1245-8. [DOI: 10.1016/j.biocel.2008.11.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2008] [Revised: 11/23/2008] [Accepted: 11/24/2008] [Indexed: 11/29/2022]
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