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T cell receptor (TCR) signaling in health and disease. Signal Transduct Target Ther 2021; 6:412. [PMID: 34897277 PMCID: PMC8666445 DOI: 10.1038/s41392-021-00823-w] [Citation(s) in RCA: 108] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 11/02/2021] [Accepted: 11/02/2021] [Indexed: 12/18/2022] Open
Abstract
Interaction of the T cell receptor (TCR) with an MHC-antigenic peptide complex results in changes at the molecular and cellular levels in T cells. The outside environmental cues are translated into various signal transduction pathways within the cell, which mediate the activation of various genes with the help of specific transcription factors. These signaling networks propagate with the help of various effector enzymes, such as kinases, phosphatases, and phospholipases. Integration of these disparate signal transduction pathways is done with the help of adaptor proteins that are non-enzymatic in function and that serve as a scaffold for various protein-protein interactions. This process aids in connecting the proximal to distal signaling pathways, thereby contributing to the full activation of T cells. This review provides a comprehensive snapshot of the various molecules involved in regulating T cell receptor signaling, covering both enzymes and adaptors, and will discuss their role in human disease.
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Comte D, Karampetsou MP, Humbel M, Tsokos GC. Signaling lymphocyte activation molecule family in systemic lupus erythematosus. Clin Immunol 2018; 204:57-63. [PMID: 30415085 DOI: 10.1016/j.clim.2018.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 11/04/2018] [Accepted: 11/05/2018] [Indexed: 01/09/2023]
Abstract
Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease characterized by a breakdown in immune tolerance leading to the development of auto-reactive lymphocytes and autoantibodies. Recent findings have provided new insight on the role of the signaling lymphocytic activation molecule family (SLAMF) receptors, a group of nine co-regulatory molecules involved in the activation of hematopoietic cells, and their downstream protein SLAM-associated protein (SAP), into the pathogenesis of SLE. This review summarizes the current knowledge on SLAMF in human SLE immunopathogenesis, and the importance of SLAMF molecules as new therapeutic targets.
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Affiliation(s)
- Denis Comte
- Divisions of Immunology and Allergy, Lausanne University Hospital, Lausanne, Switzerland.
| | | | - Morgane Humbel
- Divisions of Immunology and Allergy, Lausanne University Hospital, Lausanne, Switzerland
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Karampetsou MP, Comte D, Kis-Toth K, Terhorst C, Kyttaris VC, Tsokos GC. Decreased SAP Expression in T Cells from Patients with Systemic Lupus Erythematosus Contributes to Early Signaling Abnormalities and Reduced IL-2 Production. THE JOURNAL OF IMMUNOLOGY 2016; 196:4915-24. [PMID: 27183584 DOI: 10.4049/jimmunol.1501523] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 04/06/2016] [Indexed: 11/19/2022]
Abstract
T cells from patients with systemic lupus erythematosus (SLE) display a number of abnormalities, including increased early signaling events following engagement of the TCR. Signaling lymphocytic activation molecule family cell surface receptors and the X-chromosome-defined signaling lymphocytic activation molecule-associated protein (SAP) adaptor are important in the development of several immunocyte lineages and modulating the immune response. We present evidence that SAP protein levels are decreased in T cells and in their main subsets isolated from 32 women and three men with SLE, independent of disease activity. In SLE T cells, SAP protein is also subject to increased degradation by caspase-3. Forced expression of SAP in SLE T cells normalized IL-2 production, calcium (Ca(2+)) responses, and tyrosine phosphorylation of a number of proteins. Exposure of normal T cells to SLE serum IgG, known to contain anti-CD3/TCR Abs, resulted in SAP downregulation. We conclude that SLE T cells display reduced levels of the adaptor protein SAP, probably as a result of continuous T cell activation and degradation by caspase-3. Restoration of SAP levels in SLE T cells corrects the overexcitable lupus T cell phenotype.
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Affiliation(s)
- Maria P Karampetsou
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Denis Comte
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215; Service d'Immunologie et Allergie, Centre Hospitalier Universitaire Vaudois, CH 1011 Lausanne, Switzerland; and
| | - Katalin Kis-Toth
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Cox Terhorst
- Division of Immunology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - Vasileios C Kyttaris
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215
| | - George C Tsokos
- Division of Rheumatology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215;
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Weng X, Liao CM, Bagchi S, Cardell SL, Stein PL, Wang CR. The adaptor protein SAP regulates type II NKT-cell development, cytokine production, and cytotoxicity against lymphoma. Eur J Immunol 2014; 44:3646-57. [PMID: 25236978 DOI: 10.1002/eji.201444848] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/19/2014] [Accepted: 09/16/2014] [Indexed: 11/09/2022]
Abstract
CD1d-restricted NKT cells represent a unique lineage of immunoregulatory T cells that are divided into two groups, type I and type II, based on their TCR usage. Because there are no specific tools to identify type II NKT cells, little is known about their developmental requirements and functional regulation. In our previous study, we showed that signaling lymphocytic activation molecule associated protein (SAP) is essential for the development of type II NKT cells. Here, using a type II NKT-cell TCR transgenic mouse model, we demonstrated that CD1d-expressing hematopoietic cells, but not thymic epithelial cells, meditate efficient selection of type II NKT cells. Furthermore, we showed that SAP regulates type II NKT-cell development by controlling early growth response 2 protein and promyelocytic leukemia zinc finger expression. SAP-deficient 24αβ transgenic T cells (24αβ T cells) exhibited an immature phenotype with reduced Th2 cytokine-producing capacity and diminished cytotoxicity to CD1d-expressing lymphoma cells. The impaired IL-4 production by SAP-deficient 24αβ T cells was associated with reduced IFN regulatory factor 4 and GATA-3 induction following TCR stimulation. Collectively, these data suggest that SAP is critical for regulating type II NKT cell responses. Aberrant responses of these T cells may contribute to the immune dysregulation observed in X-linked lymphoproliferative disease caused by mutations in SAP.
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Affiliation(s)
- Xiufang Weng
- Department of Microbiology and Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Menard L, Cantaert T, Chamberlain N, Tangye SG, Riminton S, Church JA, Klion A, Cunningham-Rundles C, Nichols KE, Meffre E. Signaling lymphocytic activation molecule (SLAM)/SLAM-associated protein pathway regulates human B-cell tolerance. J Allergy Clin Immunol 2013; 133:1149-61. [PMID: 24373350 DOI: 10.1016/j.jaci.2013.10.051] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 08/28/2013] [Accepted: 10/15/2013] [Indexed: 01/15/2023]
Abstract
BACKGROUND Signaling lymphocytic activation molecule (SLAM)-associated protein (SAP) can mediate the function of SLAM molecules, which have been proposed to be involved in the development of autoimmunity in mice. OBJECTIVE We sought to determine whether the SLAM/SAP pathway regulates the establishment of human B-cell tolerance and what mechanisms of B-cell tolerance could be affected by SAP deficiency. METHODS We tested the reactivity of antibodies isolated from single B cells from SAP-deficient patients with X-linked lymphoproliferative disease (XLP). The expressions of SAP and SLAM family members were assessed in human bone marrow-developing B cells. We also analyzed regulatory T (Treg) cell function in patients with XLP and healthy control subjects. RESULTS We found that new emigrant/transitional B cells from patients with XLP were enriched in autoreactive clones, revealing a defective central B-cell tolerance checkpoint in the absence of functional SAP. In agreement with a B cell-intrinsic regulation of central tolerance, we identified SAP expression in a discrete subset of bone marrow immature B cells. SAP colocalized with SLAMF6 only in association with clustered B-cell receptors likely recognizing self-antigens, suggesting that SLAM/SAP regulate B-cell receptor-mediated central tolerance. In addition, patients with XLP displayed defective peripheral B-cell tolerance, which is normally controlled by Treg cells. Treg cells in patients with XLP seem functional, but SAP-deficient T cells were resistant to Treg cell-mediated suppression. Indeed, SAP-deficient T cells were hyperresponsive to T-cell receptor stimulation, which resulted in increased secretion of IL-2, IFN-γ, and TNF-α. CONCLUSIONS SAP expression is required for the counterselection of developing autoreactive B cells and prevents their T cell-dependent accumulation in the periphery.
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Affiliation(s)
- Laurence Menard
- Department of Immunobiology, Yale University School of Medicine, New Haven, Conn
| | - Tineke Cantaert
- Department of Immunobiology, Yale University School of Medicine, New Haven, Conn
| | - Nicolas Chamberlain
- Department of Immunobiology, Yale University School of Medicine, New Haven, Conn
| | - Stuart G Tangye
- Immunology Program, Garvan Institute of Medical Research, and St Vincent's Clinical School, University of New South Wales, Darlinghurst, Australia
| | - Sean Riminton
- Department of Immunology, Concord Hospital, Sydney, Australia
| | - Joseph A Church
- Divisions of Clinical Immunology and Allergy, Children's Hospital Los Angeles and Keck School of Medicine, University of Southern California, Los Angeles, Calif
| | - Amy Klion
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Md
| | | | - Kim E Nichols
- Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, Pa
| | - Eric Meffre
- Department of Immunobiology, Yale University School of Medicine, New Haven, Conn.
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Proust R, Bertoglio J, Gesbert F. The adaptor protein SAP directly associates with CD3ζ chain and regulates T cell receptor signaling. PLoS One 2012; 7:e43200. [PMID: 22912825 PMCID: PMC3418226 DOI: 10.1371/journal.pone.0043200] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/18/2012] [Indexed: 11/25/2022] Open
Abstract
Mutations altering the gene encoding the SLAM associated protein (SAP) are responsible for the X-linked lymphoproliferative disease or XLP1. Its absence is correlated with a defective NKT cells development, a decrease in B cell functions and a reduced T cells and NK cells cytotoxic activities, thus leading to an immunodeficiency syndrome. SAP is a small 128 amino-acid long protein that is almost exclusively composed of an SH2 domain. It has been shown to interact with the CD150/SLAM family of receptors, and in a non-canonical manner with SH3 containing proteins such as Fyn, βPIX, PKCθ and Nck1. It would thus play the role of a minimal adaptor protein. It has been shown that SAP plays an important function in the activation of T cells through its interaction with the SLAM family of receptors. Therefore SAP defective T cells display a reduced activation of signaling events downstream of the TCR-CD3 complex triggering. In the present work, we evidence that SAP is a direct interactor of the CD3ζ chain. This direct interaction occurs through the first ITAM of CD3ζ, proximal to the membrane. Additionally, we show that, in the context of the TCR-CD3 signaling, an Sh-RNA mediated silencing of SAP is responsible for a decrease of several canonical T cell signaling pathways including Erk, Akt and PLCγ1 and to a reduced induction of IL-2 and IL-4 mRNA. Altogether, we show that SAP plays a central function in the T cell activation processes through a direct association with the CD3 complex.
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Affiliation(s)
- Richard Proust
- Institut National de la Santé Et de la Recherche Médicale UMR-S1004, Université Paris-Sud, Hopital Paul Brousse, Villejuif, France
| | - Jacques Bertoglio
- Institut National de la Santé Et de la Recherche Médicale UMR-S749, Institut Gustave Roussy, Villejuif, France
| | - Franck Gesbert
- Institut National de la Santé Et de la Recherche Médicale UMR-S1004, Université Paris-Sud, Hopital Paul Brousse, Villejuif, France
- * E-mail:
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Baldanzi G, Pighini A, Bettio V, Rainero E, Traini S, Chianale F, Porporato PE, Filigheddu N, Mesturini R, Song S, Schweighoffer T, Patrussi L, Baldari CT, Zhong XP, van Blitterswijk WJ, Sinigaglia F, Nichols KE, Rubio I, Parolini O, Graziani A. SAP-mediated inhibition of diacylglycerol kinase α regulates TCR-induced diacylglycerol signaling. THE JOURNAL OF IMMUNOLOGY 2011; 187:5941-51. [PMID: 22048771 DOI: 10.4049/jimmunol.1002476] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Diacylglycerol kinases (DGKs) metabolize diacylglycerol to phosphatidic acid. In T lymphocytes, DGKα acts as a negative regulator of TCR signaling by decreasing diacylglycerol levels and inducing anergy. In this study, we show that upon costimulation of the TCR with CD28 or signaling lymphocyte activation molecule (SLAM), DGKα, but not DGKζ, exits from the nucleus and undergoes rapid negative regulation of its enzymatic activity. Inhibition of DGKα is dependent on the expression of SAP, an adaptor protein mutated in X-linked lymphoproliferative disease, which is essential for SLAM-mediated signaling and contributes to TCR/CD28-induced signaling and T cell activation. Accordingly, overexpression of SAP is sufficient to inhibit DGKα, whereas SAP mutants unable to bind either phospho-tyrosine residues or SH3 domain are ineffective. Moreover, phospholipase C activity and calcium, but not Src-family tyrosine kinases, are also required for negative regulation of DGKα. Finally, inhibition of DGKα in SAP-deficient cells partially rescues defective TCR/CD28 signaling, including Ras and ERK1/2 activation, protein kinase C membrane recruitment, induction of NF-AT transcriptional activity, and IL-2 production. Thus SAP-mediated inhibition of DGKα sustains diacylglycerol signaling, thereby regulating T cell activation, and it may represent a novel pharmacological strategy for X-linked lymphoproliferative disease treatment.
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Affiliation(s)
- Gianluca Baldanzi
- Department of Clinical and Experimental Medicine, University A. Avogadro of Piemonte Orientale, 28100 Novara, Italy.
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Abstract
The signaling lymphocyte activation molecule (SLAM)-associated protein, SAP, was first identified as the protein affected in most cases of X-linked lymphoproliferative (XLP) syndrome, a rare genetic disorder characterized by abnormal responses to Epstein-Barr virus infection, lymphoproliferative syndromes, and dysgammaglobulinemia. SAP consists almost entirely of a single SH2 protein domain that interacts with the cytoplasmic tail of SLAM and related receptors, including 2B4, Ly108, CD84, Ly9, and potentially CRACC. SLAM family members are now recognized as important immunomodulatory receptors with roles in cytotoxicity, humoral immunity, autoimmunity, cell survival, lymphocyte development, and cell adhesion. In this review, we cover recent findings on the roles of SLAM family receptors and the SAP family of adaptors, with a focus on their regulation of the pathways involved in the pathogenesis of XLP and other immune disorders.
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Affiliation(s)
- Jennifer L Cannons
- National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
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SLAM receptors and SAP influence lymphocyte interactions, development and function. Nat Rev Immunol 2009; 9:39-46. [PMID: 19079134 DOI: 10.1038/nri2456] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Mutations that affect the adaptor molecule SLAM-associated protein (SAP) underlie the primary immunodeficiency disease X-linked lymphoproliferative syndrome. SAP is required for mediating signals from members of the signalling lymphocytic activation molecule (SLAM) family of immunomodulatory receptors. Recent data have highlighted a role for SAP in the development of innate-like T-cell lineages, including natural killer T cells, and in the regulation of the interactions between B cells and T cells that are required for germinal-centre formation and long-term humoral immunity. These data have revealed that SLAM family members and SAP have crucial roles in regulating lymphocyte interactions and adhesion, which are required for the normal development, homeostasis and function of the immune system.
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Ostrakhovitch EA, Wang Y, Li SSC. SAP binds to CD22 and regulates B cell inhibitory signaling and calcium flux. Cell Signal 2008; 21:540-50. [PMID: 19150402 DOI: 10.1016/j.cellsig.2008.12.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 12/10/2008] [Accepted: 12/15/2008] [Indexed: 01/25/2023]
Abstract
The signaling lymphocyte activation molecule (SLAM)-associated protein (SAP or SH2D1A) is an important regulator of immune function which, when mutated or deleted, causes the X-linked lymphoproliferative syndrome (XLP). Because B cell lymphoma is a major phenotype of XLP, it is important to understand the function of SAP in B cells. Here we report that SAP is expressed endogenously in mouse splenic B cells, is inducibly expressed in the human BJAB cells, and co-localizes and interacts with CD22. We also show that SAP binding to the inhibitory immunoreceptor CD22 regulates calcium mobilization in B cells. Moreover, forced expression of SAP leads to constitutive CD22 tyrosine phosphorylation and decreased Ca(2+) response in B cells. Biochemical analysis reveals that, in response to IgM cross-linking, the phosphorylation of Syk, Blnk, or PLCgamma2 and their interactions with one another were either diminished or completely abolished in SAP-expressing cells compared to cells that lack SAP. Collectively our work identifies a novel role for SAP in B cells and extends its function to inhibitory immunoreceptor signaling and calcium mobilization.
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Affiliation(s)
- Elena A Ostrakhovitch
- Department of Biochemistry and the Siebens-Drake Research Institute, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1.
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Mehrle S, Schmidt J, Büchler MW, Watzl C, Märten A. Enhancement of anti-tumor activity in vitro and in vivo by CD150 and SAP. Mol Immunol 2008; 45:796-804. [PMID: 17692919 DOI: 10.1016/j.molimm.2007.06.361] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Accepted: 06/04/2007] [Indexed: 11/23/2022]
Abstract
Signaling lymphocyte activation molecule (SLAM, CD150) is a co-stimulatory receptor involved in T cell activation. The activity of CD150 is dependent on the intracellular signaling molecule SAP. Here, we investigated anti-CD3 activated human lymphocytes, transfected either with CD150-plasmid or with CD150- or SAP-siRNA in cytotoxicity assays against human colon cancer cells in vitro and in a xenograft model (CB/Scid/CrL mice) in vivo. Up-regulation or silencing of CD150 was accompanied by increased or decreased cytotoxic activity, respectively. Similar effects could also be shown in an IFN-gamma ELISpot assay. Furthermore, CD150 co-localized after activation with lipid rafts in specific membrane compartments on CD8 T cells. Treatment of xenografted mice with CD150 over-expressing lymphocytes decelerated tumor growth significantly. Lymphocytes were detectable in spleen 18 days after injection and expressed mainly CD8, CD45RO and CD150 above average. In conclusion, over-expression of CD150 in lymphocytes is accompanied with enhanced cytotoxic activity and IFN-gamma secretion in vitro and anti-tumor activity in vivo, whereas silencing of CD150 down-regulates effector functions. Adoptive cell transfer of CD150 over-expressing lymphocytes results in an accumulation of CD8, CD45RO and CD150 cells in tumor and spleen indicating together with the observed CD150 co-localization with lipid rafts that CD150 mediates a Th1 response.
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Affiliation(s)
- Stefan Mehrle
- Department of Surgery, University of Heidelberg, 69120 Heidelberg, Germany
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Gu C, Tangye SG, Sun X, Luo Y, Lin Z, Wu J. The X-linked lymphoproliferative disease gene product SAP associates with PAK-interacting exchange factor and participates in T cell activation. Proc Natl Acad Sci U S A 2006; 103:14447-52. [PMID: 16983070 PMCID: PMC1599982 DOI: 10.1073/pnas.0606624103] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2006] [Indexed: 01/28/2023] Open
Abstract
SLAM (signaling lymphocyte activation molecule)-associated protein (SAP) is a Src homology 2 (SH2) domain-containing adaptor expressed in T cells and natural killer cells. Its essential role in immune responses is underscored by the recent finding that mutations in SAP result in a rare but fatal X-linked lymphoproliferative disease (XLP). Although SAP is known to associate with SLAM-family receptors, the exact molecular mechanism by which SAP regulates lymphocyte signaling remains elusive. We here report that in T cells, SAP associates with the PAK-interacting exchange factor (PIX), a guanine nucleotide exchange factor (GEF) specific for Rac/Cdc42 GTPases. Moreover, SAP, PIX, and an activated form of Cdc42 form a complex in mammalian cells. We demonstrate that the SAP-PIX interaction is specific and is mediated by the C-terminal region of the SAP SH2 domain and the PIX SH3 domain. We further show that SAP is required for the recruitment of PIX to the SLAM-family receptors. Interestingly, overexpression of SAP, but not its homolog EAT-2, leads to a synergistic activation of nuclear factor of activating T cells (NFAT) in combination with a calcium signal in T cells. This SAP-mediated activation appears to be receptor-dependent and can be blocked by a dominant negative form of PIX. Taken together, our data strongly suggest that, in addition to the known SAP-interacting kinase Fyn, PIX may be another key player in SAP-mediated T cell activation.
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Affiliation(s)
- Cuiping Gu
- *Department of Life Science and Biotechnology, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, China
- Shanghai Genomics, Inc., Zhangjiang Hi-Tech Park, Shanghai 201203, China; and
| | - Stuart G. Tangye
- Immunology and Inflammation Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, New South Wales 2010, Australia
| | - Xiaoqing Sun
- Chinese National Genome Center
- Shanghai Genomics, Inc., Zhangjiang Hi-Tech Park, Shanghai 201203, China; and
| | - Ying Luo
- *Department of Life Science and Biotechnology, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, China
- Chinese National Genome Center
- Shanghai Genomics, Inc., Zhangjiang Hi-Tech Park, Shanghai 201203, China; and
- GNI Ltd., 4-2-12 Toranomon, Tokyo 105-0001, Japan
| | - Zhixin Lin
- *Department of Life Science and Biotechnology, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, China
| | - Jun Wu
- *Department of Life Science and Biotechnology, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030, China
- Chinese National Genome Center
- Shanghai Genomics, Inc., Zhangjiang Hi-Tech Park, Shanghai 201203, China; and
- GNI Ltd., 4-2-12 Toranomon, Tokyo 105-0001, Japan
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Hare NJ, Ma CS, Alvaro F, Nichols KE, Tangye SG. Missense mutations in SH2D1A identified in patients with X-linked lymphoproliferative disease differentially affect the expression and function of SAP. Int Immunol 2006; 18:1055-65. [PMID: 16720617 DOI: 10.1093/intimm/dxl039] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
X-linked lymphoproliferative disease (XLP) is an immunodeficiency resulting from mutations in SH2D1A, which encodes signalling lymphocytic activation molecule (SLAM)-associated protein (SAP). In addition to SLAM, SAP associates with several other cell-surface receptors including 2B4 (CD244), Ly9 (CD229), CD84 and NTB-A. SAP contains a single src-homology-2 domain and acts as an intracellular adaptor protein by recruiting the protein tyrosine kinase FynT to the cytoplasmic domains of some of these receptors, which results in the initiation of specific downstream signal transduction pathways. XLP is likely to result from perturbed signalling through one or more of these SAP-associating receptors. In this study, we identified missense (Y54C, I84T and F87S) and insertion (fs82 --> X103) mutations in four different kindreds affected by XLP. Each mutation dramatically reduced the half-life of SAP, thus diminishing its expression in primary lymphocytes as well as in transfected cell lines. Interestingly, although the Y54C and F87S mutations compromised the ability of SAP to associate with different receptors, the I84T mutation had no effect on the ability of SAP to bind SLAM, CD84 or 2B4. However, signalling downstream of SLAM was reduced in the presence of SAP bearing the I84T mutation. These findings indicate that, irrespective of the type of mutation, signalling through SAP-associating receptors in XLP can be impaired by reducing the expression of SAP, the ability of SAP to bind surface receptors and/or its ability to activate signal transduction downstream of the SLAM-SAP complex.
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Affiliation(s)
- Nathan J Hare
- Lymphocyte Differentiation, Centenary Institute for Cancer Medicine and Cell Biology, Locked Bag No. 6, Newtown, New South Wales 2042, Australia
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Mehrle S, Frank S, Schmidt J, Schmidt-Wolf IG, Märten A. SAP and SLAM expression in anti-CD3 activated lymphocytes correlates with cytotoxic activity. Immunol Cell Biol 2005; 83:33-9. [PMID: 15661039 DOI: 10.1111/j.1440-1711.2004.01302.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Signalling lymphocyte activation molecule (SLAM)-associated protein (SAP) is a small protein that is mutant in humans with X-linked lymphoproliferative (XLP) disease. Patients with XLP disease are affected by fatal EBV infection and malignant B-cell lymphomas. The increased risk for B-cell lymphomas is suggested to result from impaired immunosurveillance of B-cell proliferation by T cells. In this study, we investigated the role of SLAM and SAP in activation of effector cells with cytotoxic activity, cytokine-induced killer (CIK) cells, which are generated by non-specific stimulation of the TCR and addition of exogenous IL-2. Agonistic TCR activation 1 day after preparation (day +1) resulted in cell activation, with a peak of SLAM on day +6 visible at both the protein and mRNA level as well as membrane detectable SLAM. This increase in SLAM expression correlated significantly with SAP expression at the mRNA level as well as at the protein level. Cytotoxic activity peaked 1 day after the observed SAP and SLAM peaks. At that point in time, IL-10 secretion, which was high during the early days of culture, decreased. In conclusion, activation of peripheral blood cells with agonistic anti-CD3 antibody and exogenous IL-2, as used for generation of CIK cells, results in significant SLAM and SAP activation 5 days after TCR stimulation. This peak correlates with cytotoxic activity against tumour cells. Expression of SLAM and SAP seems to be important in the activation of cytotoxic effector cells.
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Affiliation(s)
- Stefan Mehrle
- Department of Surgery, University of Heidelberg, Heidelberg, Germany
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Mehrle S, Frank S, Schmidt J, Schmidt‐Wolf IGH, Märten A. SAP and SLAM expression in anti‐CD3 activated lymphocytes correlates with cytotoxic activity. Immunol Cell Biol 2005. [DOI: 10.1111/j.1440-1711.2005.01302.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stefan Mehrle
- Department of Surgery, University of Heidelberg Heidelberg
| | - Susanne Frank
- Department of Internal Medicine I, University of Bonn Bonn Germany
| | - Jan Schmidt
- Department of Surgery, University of Heidelberg Heidelberg
| | | | - Angela Märten
- Department of Surgery, University of Heidelberg Heidelberg
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Dupré L, Andolfi G, Tangye SG, Clementi R, Locatelli F, Aricò M, Aiuti A, Roncarolo MG. SAP controls the cytolytic activity of CD8+ T cells against EBV-infected cells. Blood 2005; 105:4383-9. [PMID: 15677558 DOI: 10.1182/blood-2004-08-3269] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The adaptor protein SAP regulates signaling through signaling lymphocytic activation molecule (SLAM)-family receptors expressed on T and natural killer (NK) cells. In patients affected by X-linked lymphoproliferative (XLP) disease, mutations in the SH2D1A gene result in defective lytic activity. However, the mechanism by which SAP controls cytotoxic activity remains unclear. T-cell-receptor (TCR) activation of CD8(+) cytotoxic T cells (CTLs) results in down-regulation of SAP, suggesting that this protein is involved in early activation events. Here, we show that SAP-deficient CTLs from patients with XLP and hemophagocytic lymphohistiocytosis (HLH) display a specific lytic defect against autologous and allogeneic Epstein-Barr virus (EBV)-positive B cells. This defect is associated with the defective polarization of 2B4, perforin, and lipid rafts at the contact area of CTLs with EBV-positive targets. Blockade of 2B4 in normal CTLs reproduces the defects in lysis and polarization observed in SAP-deficient CTLs. Expression and regulation of the SLAM-family receptors SLAM, CD84, and 2B4, as well as the lytic effectors perforin and granzyme-B are normal in SAP-deficient CTLs. In addition, TCR stimulation leads to normal proliferation and production of interleukin 2 (IL-2), IL-4, and interferon-gamma (IFN-gamma). These results demonstrate that the SAP/2B4 pathway plays a key role in CTL lytic activity against EBV-positive targets by promoting the polarization of the lytic machinery.
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Affiliation(s)
- Loïc Dupré
- San Raffaele Telethon Institute for Gene Therapy, via Olgettina 58, 20132 Milan, Italy
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Cannons JL, Yu LJ, Hill B, Mijares LA, Dombroski D, Nichols KE, Antonellis A, Koretzky GA, Gardner K, Schwartzberg PL. SAP regulates T(H)2 differentiation and PKC-theta-mediated activation of NF-kappaB1. Immunity 2004; 21:693-706. [PMID: 15539155 DOI: 10.1016/j.immuni.2004.09.012] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2004] [Revised: 08/27/2004] [Accepted: 09/14/2004] [Indexed: 01/18/2023]
Abstract
XLP is caused by mutations affecting SAP, an adaptor that recruits Fyn to SLAM family receptors. SAP-deficient mice recapitulate features of XLP, including increased T cell activation and decreased humoral responses post-infection. SAP-deficient T cells also show increased TCR-induced IFN-gamma and decreased T(H)2 cytokine production. We demonstrate that the defect in IL-4 secretion in SAP-deficient T cells is independent of increased IFN-gamma production. SAP-deficient cells respond normally to polarizing cytokines, yet show impaired TCR-mediated induction of GATA-3 and IL-4. Examination of TCR signaling revealed normal Ca(2+) mobilization and ERK activation in SAP-deficient cells, but decreased PKC-theta recruitment, Bcl-10 phosphorylation, IkappaB-alpha degradation, and nuclear NF-kappaB1/p50 levels. Similar defects were observed in Fyn-deficient cells. SLAM engagement amplified PKC-theta recruitment in wt but not SAP- or Fyn-deficient cells, arguing that a SAP/Fyn-mediated pathway enhances PKC-theta/NF-kappaB1 activation and suggesting a role for this pathway in T(H)2 regulation.
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Affiliation(s)
- Jennifer L Cannons
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, USA
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18
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Abstract
SAP and EAT-2 define a new class of adaptor proteins composed almost exclusively of a Src homology 2 (SH2) domain. By way of their SH2 domain, SAP-like adaptors interact with tyrosine-based motifs in the cytoplasmic region of SLAM-related receptors, a family of immune cell-specific molecules involved in immunoregulation. Recent findings indicate that SAP is required for the functions of SLAM family receptors, as a consequence of its ability to promote recruitment of Src-related protein tyrosine kinase FynT and allow SLAM-related receptors to transduce tyrosine phosphorylation signals. SAP is mutated in X-linked lymphoproliferative (XLP) syndrome, a rare inherited human disease characterized by an deregulated immune response to Epstein-Barr virus infection. Several lines of evidence indicate that defects in the activities of SLAM-related receptors caused by SAP deficiency account for the immune dysfunctions associated with XLP.
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Affiliation(s)
- Sylvain Latour
- Unité INSERM U429, Hôpital Necker Enfants-Malades, 149 rue de Sèvres, 75015 Paris, France.
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Abstract
Recent advances in molecular genetics have allowed identification of at least seven genes involved in X-linked immunodeficiencies. This has resulted not only in improved diagnostic possibilities but also in a better understanding of the pathophysiology of these disorders. In some cases, mutations in the same gene have been shown to cause distinct clinical and immunologic phenotypes, demonstrating a strong genotype-phenotype correlation. Identification of the molecular basis of these diseases has permitted creation of disease-specific registries, with a better characterization of the clinical and immunologic features associated with the various forms of X-linked immunodeficiencies. Additionally, gene therapy has been attempted in X-linked severe combined immune deficiency (XSCID), with clear evidence of successful correction of the pathology, and the appearance of severe adverse effects.
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Affiliation(s)
- Hans D Ochs
- Department of Pediatrics, University of Washington, Children's Hospital and Regional Medical Center, 4800 Sand Point Way NE, Seattle, WA 98105, USA.
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Cannons JL, Schwartzberg PL. Fine-tuning lymphocyte regulation: what’s new with tyrosine kinases and phosphatases? Curr Opin Immunol 2004; 16:296-303. [PMID: 15134778 DOI: 10.1016/j.coi.2004.03.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Although the basic mechanisms of lymphocyte signaling have been established, recent studies have provided new insights into how fine-tuning the regulation of tyrosine kinases and phosphatases contributes to the delicate balance required for appropriate lymphocyte activation. Recent studies include new work on the roles of the immune synapse in regulating T-cell receptor signaling, the discovery of new functions for the Src-family kinase Fyn and the Tec kinase Itk, particularly in regulation of the actin cytoskeleton, and new insights into positive and negative feedback mechanisms in antigen receptor signaling.
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Affiliation(s)
- Jennifer L Cannons
- National Human Genome Research Institute, 49/4A38, 49 Convent Drive, National Institutes of Health, Bethesda, MD 20892, USA.
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Sharifi R, Sinclair JC, Gilmour KC, Arkwright PD, Kinnon C, Thrasher AJ, Gaspar HB. SAP mediates specific cytotoxic T-cell functions in X-linked lymphoproliferative disease. Blood 2004; 103:3821-7. [PMID: 14726378 DOI: 10.1182/blood-2003-09-3359] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Cytotoxic T cells (CTLs) and natural killer cells play a major role in the immune response to Epstein-Barr virus (EBV) infection. In X-linked lymphoproliferative (XLP) disease, a severe immunodeficiency, immunodysregulatory phenomena are observed following EBV infection, suggesting that defects exist in these effector populations. The gene defective in XLP is SAP (signaling lymphocytic activation molecule [SLAM]–associated protein), an adaptor protein that mediates signals through SLAM and other immunoglobulin superfamily receptors including 2B4. We generated EBV-specific T-cell lines from controls and XLP patients and examined CTL function in response to different stimuli. We show that XLP patients can generate EBV–T-cell lines that are phenotypically similar to those from controls. XLP patient EBV–T-cell lines showed a significant decrease in interferon-gamma (IFN-γ) production in response to 2B4 and autologous EBV-transformed lymphoblastoid cell line (LCL) stimulation but not in response to SLAM. Furthermore, XLP EBV–T-cell lines demonstrated markedly decreased cytotoxic activity against autologous LCLs. By retroviral gene transfer of the SAP gene into XLP EBV–T-cell lines, we show reconstitution of IFN-γ production and of cytotoxic activity confirming SAP-dependent defects. These studies demonstrate that in XLP the lack of SAP affects specific signaling pathways resulting in severe disruption of CTL function.
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Affiliation(s)
- Reza Sharifi
- Molecular Immunology Unit, Institute of Child Health, University College London, London, United Kingdom
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