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Iseki M, Hidano S, Kudo F, Takaki S. Control of germinal center B cell survival and IgE production by an adaptor molecule containing PH and SH2 domains, Aps/Sh2b2. Sci Rep 2024; 14:17767. [PMID: 39090233 PMCID: PMC11294469 DOI: 10.1038/s41598-024-68739-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 07/26/2024] [Indexed: 08/04/2024] Open
Abstract
The germinal centers (GCs) are structure found within secondary lymphoid organs and are important for the antibody-producing response against foreign antigens. In GCs, antigen-specific B cells proliferate intensely, inducing immunoglobulin class switching. Recent studies have shown that GCs are also an important site for class switching to IgE, which is implicated in allergy. However, the mechanisms by which IgE production is regulated in GCs remain unclear. Here, we found impairment in IgE-specific production and a reduction of GC B cells after immunization in mice deficient in the Aps/Sh2b2 gene encoding the Lnk/Sh2b family adaptor protein Aps. GC B cells express higher levels of the Aps gene than non-GC B cells, and cell death of Aps-/- GC B cells is enhanced compared to wild-type GC B cells. An in vitro culture system with purified Aps-/- B cells induced the same level of IgE production and frequencies of IgE+ B cells as wild-type B cells. We found that Aps deficiency in B cells resulted in augmented depletion of IgE+ blasts by B cell receptor crosslinking with anti-CD79b antibodies compared to wild-type IgE+ cells. These results suggest that Aps regulates IgE production by controlling the survival of GC B cells and IgE+ plasma cells and may serve as a potential therapeutic target to control IgE production.
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Affiliation(s)
- Masanori Iseki
- Department of Immune Regulation, The Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan.
- Department of Immunology and Molecular Genetics, Kawasaki Medical School, Kurashiki, Okayama, Japan.
| | - Shinya Hidano
- Department of Immune Regulation, The Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan
| | - Fujimi Kudo
- Department of Immune Regulation, The Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan
- Department of Systems Medicine, Chiba University Graduate School of Medicine, Inohana, Chuo-Ku, Chiba, Japan
| | - Satoshi Takaki
- Department of Immune Regulation, The Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, Ichikawa, Chiba, Japan
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2
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X-linked immunodeficient (XID) mice exhibit high susceptibility to Cryptococcus gattii infection. Sci Rep 2021; 11:18397. [PMID: 34526536 PMCID: PMC8443669 DOI: 10.1038/s41598-021-97041-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 08/19/2021] [Indexed: 12/12/2022] Open
Abstract
Cryptococcosis is an opportunistic disease caused by the fungus Cryptococcus neoformans and Cryptococcus gattii. It starts as a pulmonary infection that can spread to other organs, such as the brain, leading to the most serious occurrence of the disease, meningoencephalitis. The humoral response has already been described in limiting the progression of cryptococcosis where the B-1 cell seems to be responsible for producing natural IgM antibodies, crucial for combating fungal infections. The role of the B-1 cell in C. neoformans infection has been initially described, however the role of the humoral response of B-1 cells has not yet been evaluated during C. gattii infections. In the present study we tried to unravel this issue using XID mice, a murine model deficient in the Btk protein which compromises the development of B-1 lymphocytes. We use the XID mice compared to BALB/c mice that are sufficient for the B-1 population during C. gattii infection. Our model of chronic lung infection revealed that XID mice, unlike the sufficient group of B-1, had early mortality with significant weight loss, in addition to reduced levels of IgM and IgG specific to GXM isolated from the capsule of C. neoformans. In addition to this, we observed an increased fungal load in the blood and in the brain. We described an increase in the capsular size of C. gattii and the predominant presence of cytokines with a Th2 profile was also observed in these animals. Thus, the present study strongly points to a higher susceptibility of the XID mouse to C. gattii, which suggests that the presence of B-1 cells and anti-GXM antibodies is fundamental during the control of infection by C. gattii.
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Dondi E, Sibarita JB, Varin-Blank N, Velazquez L. The adaptor protein APS modulates BCR signalling in mature B cells. Cell Signal 2020; 73:109673. [PMID: 32470518 DOI: 10.1016/j.cellsig.2020.109673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 11/19/2022]
Abstract
Activation process of mature B cell is predominantly driven by specific BCR-mediated pathways, switched on and off all through late B cell differentiation stages. Mice deficient for APS, a member of the Lnk/SH2B family of adaptor proteins, showed that this adaptor plays a BCR-mediated regulatory role in mature B cells. However, the intermediates involved in this adaptor modulating functions in B cells are still unknown. In the present study, we investigated the role of APS in regulating BCR signalling notably through cytoskeleton remodeling in mature B cells. Herein, we showed that APS function is stage specific, as it exclusively intervenes in mature B cells. Upon activation, APS colocalizes with the BCR and associates with important regulators of BCR signalling, such as Syk and Cbl kinase. Importantly, APS interferes, as a scaffold protein, with the stability of Syk kinase by recruiting Cbl. This function is mainly mediated by APS SH2 domain, which regulates BCR-evoked cell dynamics. Our findings thus reveal that APS plays a regulatory role in BCR-induced responses by specifically modulating its interacting partners, which positions APS as a relevant modulator of BCR signalling in mature B cells.
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Affiliation(s)
- Elisabetta Dondi
- INSERM, U978, UFR SMBH, Bobigny, France; Comue USPC, Labex Inflamex, Université Paris 13, UFR SMBH, Bobigny, France
| | - Jean-Baptiste Sibarita
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, Bordeaux, France; CNRS UMR, 5297 Bordeaux, France
| | - Nadine Varin-Blank
- INSERM, U978, UFR SMBH, Bobigny, France; Comue USPC, Labex Inflamex, Université Paris 13, UFR SMBH, Bobigny, France.
| | - Laura Velazquez
- INSERM, U978, UFR SMBH, Bobigny, France; Comue USPC, Labex Inflamex, Université Paris 13, UFR SMBH, Bobigny, France.
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Sh3bp2 Gain-Of-Function Mutation Ameliorates Lupus Phenotypes in B6.MRL- Faslpr Mice. Cells 2019; 8:cells8050402. [PMID: 31052273 PMCID: PMC6562867 DOI: 10.3390/cells8050402] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 04/11/2019] [Accepted: 04/27/2019] [Indexed: 02/07/2023] Open
Abstract
SH3 domain-binding protein 2 (SH3BP2) is an adaptor protein that is predominantly expressed in immune cells, and it regulates intracellular signaling. We had previously reported that a gain-of-function mutation in SH3BP2 exacerbates inflammation and bone loss in murine arthritis models. Here, we explored the involvement of SH3BP2 in a lupus model. Sh3bp2 gain-of-function (P416R knock-in; Sh3bp2KI/+) mice and lupus-prone B6.MRL-Faslpr mice were crossed to yield double-mutant (Sh3bp2KI/+Faslpr/lpr) mice. We monitored survival rates and proteinuria up to 48 weeks of age and assessed renal damage and serum anti-double-stranded DNA antibody levels. Additionally, we analyzed B and T cell subsets in lymphoid tissues by flow cytometry and determined the expression of apoptosis-related molecules in lymph nodes. Sh3bp2 gain-of-function mutation alleviated the poor survival rate, proteinuria, and glomerulosclerosis and significantly reduced serum anti-dsDNA antibody levels in Sh3bp2KI/+Faslpr/lpr mice. Additionally, B220+CD4−CD8− T cell population in lymph nodes was decreased in Sh3bp2KI/+Faslpr/lpr mice, which is possibly associated with the observed increase in cleaved caspase-3 and tumor necrosis factor levels. Sh3bp2 gain-of-function mutation ameliorated clinical and immunological phenotypes in lupus-prone mice. Our findings offer better insight into the unique immunopathological roles of SH3BP2 in autoimmune diseases.
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Velazquez L. The Lnk adaptor protein: a key regulator of normal and pathological hematopoiesis. Arch Immunol Ther Exp (Warsz) 2012; 60:415-29. [PMID: 22990499 DOI: 10.1007/s00005-012-0194-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 08/06/2012] [Indexed: 01/24/2023]
Abstract
The development and function of blood cells are regulated by specific growth factors/cytokines and their receptors' signaling pathways. In this way, these factors influence cell survival, proliferation and differentiation of hematopoietic cells. Central to this positive and/or negative control are the adaptor proteins. Since their identification 10 years ago, members of the Lnk adaptor protein family have proved to be important activators and/or inhibitors in the hematopoietic, immune and vascular system. In particular, the generation of animal and cellular models for the Lnk and APS proteins has helped establish the physiological role of these molecules through the identification of their specific signaling pathways and the characterization of their binding partners. Moreover, the recent identification of mutations in the LNK gene in myeloproliferative disorders, as well as the correlation of a single nucleotide polymorphism on LNK with hematological, immune and vascular diseases have suggested its involvement in the pathophysiology of these malignancies. The latter findings have thus raised the possibility of addressing Lnk signaling for the treatment of certain human diseases. This review therefore describes the pathophysiological role of this adaptor protein in hematological malignancies and the potential benefits of Lnk therapeutic targeting.
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Affiliation(s)
- Laura Velazquez
- UMR U978 Inserm/Université Paris 13, UFR SMBH, Bobigny, France.
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Devallière J, Chatelais M, Fitau J, Gérard N, Hulin P, Velazquez L, Turner CE, Charreau B. LNK (SH2B3) is a key regulator of integrin signaling in endothelial cells and targets α-parvin to control cell adhesion and migration. FASEB J 2012; 26:2592-606. [PMID: 22441983 DOI: 10.1096/fj.11-193383] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Focal adhesion (FA) formation and disassembly play an essential role in adherence and migration of endothelial cells. These processes are highly regulated and involve various signaling molecules that are not yet completely identified. Lnk [Src homology 2-B3 (SH2B3)] belongs to a family of SH2-containing proteins with important adaptor functions. In this study, we showed that Lnk distribution follows that of vinculin, localizing Lnk in FAs. Inhibition of Lnk by RNA interference resulted in decreased spreading, whereas sustained expression dramatically increases the number of focal and cell-matrix adhesions. We demonstrated that Lnk expression impairs FA turnover and cell migration and regulates β1-integrin-mediated signaling via Akt and GSK3β phosphorylation. Moreover, the α-parvin protein was identified as one of the molecular targets of Lnk responsible for impaired FA dynamics and cell migration. Finally, we established the ILK protein as a new molecular partner for Lnk and proposed a model in which Lnk regulates α-parvin expression through its interaction with ILK. Collectively, our results underline the adaptor Lnk as a novel and effective key regulator of integrin-mediated signaling controlling endothelial cell adhesion and migration.
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Affiliation(s)
- Julie Devallière
- Institut National de la Santé et de la Recherche Médicale (INSERM), Unité Mixte de Recherche (UMR) 643, Nantes, France
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Devallière J, Charreau B. The adaptor Lnk (SH2B3): an emerging regulator in vascular cells and a link between immune and inflammatory signaling. Biochem Pharmacol 2011; 82:1391-402. [PMID: 21723852 DOI: 10.1016/j.bcp.2011.06.023] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 12/20/2022]
Abstract
A better knowledge of the process by which inflammatory extracellular signals are relayed from the plasma membrane to specific intracellular sites is a key step to understand how inflammation develops and how it is regulated. This review focuses on Lnk (SH2B3) a member, with SH2B1 and SH2B2, of the SH2B family of adaptor proteins that influences a variety of signaling pathways mediated by Janus kinase and receptor tyrosine kinases. SH2B adaptor proteins contain conserved dimerization, pleckstrin homology, and SH2 domains. Initially described as a regulator of hematopoiesis and lymphocyte differentiation, Lnk now emerges as a key regulator in hematopoeitic and non hematopoeitic cells such as endothelial cells (EC) moderating growth factor and cytokine receptor-mediated signaling. In EC, Lnk is a negative regulator of TNF signaling that reduce proinflammatory phenotype and prevent EC from apoptosis. Lnk is a modulator in integrin signaling and actin cytoskeleton organization in both platelets and EC with an impact on cell adhesion, migration and thrombosis. In this review, we discuss some recent insights proposing Lnk as a key regulator of bone marrow-endothelial progenitor cell kinetics, including the ability to cell growth, endothelial commitment, mobilization, and recruitment for vascular regeneration. Finally, novel findings also provided evidences that mutations in Lnk gene are strongly linked to myeloproliferative disorders but also autoimmune and inflammatory syndromes where both immune and vascular cells display a role. Overall, these studies emphasize the importance of the Lnk adaptor molecule not only as prognostic marker but also as potential therapeutic target.
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Rider L, Tao J, Snyder S, Brinley B, Lu J, Diakonova M. Adapter protein SH2B1beta cross-links actin filaments and regulates actin cytoskeleton. Mol Endocrinol 2009; 23:1065-76. [PMID: 19342444 DOI: 10.1210/me.2008-0428] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The Src homology 2 (SH2) domain-containing adapter protein SH2B1beta plays a role in severe obesity, leptin and insulin resistance, and infertility. SH2B1beta was initially identified as a Janus tyrosine kinase 2 (JAK2) substrate, and it has been implicated in cell motility and regulation of the actin rearrangement in response to GH and platelet-derived growth factor. SH2B1beta is also required for maximal actin-based motility of Listeria. Here we have used a low-speed pelleting assay and electron microscopy to demonstrate that SH2B1beta has two actin-binding sites and that it cross-links actin filaments in vitro. Wild-type SH2B1beta localized to cell ruffles and along filopodia, but deletion of amino acids 150-200 (the first actin-binding site) led to mislocalization of the protein to filopodia tip complexes where it colocalized with vasodilator-stimulated phosphoprotein (VASP). Based on studies performed in VASP-deficient MVD7(-/-) cells, with or without green fluorescent protein-VASP reconstitution, we concluded that the proper intracellular localization of native SH2B1beta required the presence of the first SH2B1beta actin-binding site and VASP. Finally, we found that both SH2B1beta actin-binding domains were required for maximal GH- and prolactin-induced cell ruffling. Together, these results suggest that SH2B1beta functions as an adapter protein that cross-links actin filaments, leading to modulation of cellular responses in response to JAK2 activation.
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Affiliation(s)
- Leah Rider
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606-3390, USA
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9
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Takaki S. [Sh2b3/Lnk family adaptor proteins in the regulation of lymphohematopoiesis]. NIHON RINSHO MEN'EKI GAKKAI KAISHI = JAPANESE JOURNAL OF CLINICAL IMMUNOLOGY 2009; 31:440-7. [PMID: 19122374 DOI: 10.2177/jsci.31.440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Sh2b3/Lnk consisting of an N-terminal proline-rich region, PH-, SH2-domains and a tyrosine phosphorylation site, forms an intracellular adaptor protein family conserved from drosophila to mammals, together with Sh2b1/SH2-B and Sh2b2/APS (adaptor protein with PH and SH2 domains). Lnk negatively regulates lymphopoiesis and early hematopoiesis. The lnk-deficiency results in enhanced production of B cells, and expansion as well as enhanced function of hematopoietic stem cells (HSCs), demonstrating negative regulatory functions of Sh2b3/Lnk in cytokine signaling. Our recent studies also revealed that Sh2b3/Lnk functions in responses controlled by cell adhesion and in crosstalk between integrin- and cytokine-mediated signaling. Importantly, recent genome-wide association studies of the autoimmune type 1 diabetes or celiac disease identified risk variants in the SH2B3/LNK region, indicating possible unrevealed functions mediated by this adaptor molecule. This review summarizes roles of Sh2b3/Lnk in the regulation of B-lymphopoiesis and HSCs expansion and function, and briefly introduces our approach for modulating HSCs function by targeting Sh2b3/Lnk-mediated pathways.
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Affiliation(s)
- Satoshi Takaki
- Research Institute, International Medical Center of Japan
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10
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Lnk adaptor protein down-regulates specific Kit-induced signaling pathways in primary mast cells. Blood 2008; 112:4039-47. [DOI: 10.1182/blood-2008-05-154849] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
AbstractStem cell factor (SCF) plays critical roles in proliferation, survival, migration, and function of hematopoietic progenitor and mast cells through binding to Kit receptor. Previous studies have implicated the adaptor protein Lnk as an important negative regulator of SCF signaling. However, the molecular mechanism underlying this regulation is unclear. Here, we showed that the Src homology 2 domain (SH2) of Lnk binds directly and preferentially to phosphorylated tyrosine 567 in Kit juxtamembrane domain. Using Lnk−/− bone marrow mast cells (BMMCs) transduced with different Lnk proteins, we demonstrated that Lnk down-regulates SCF-induced proliferation with attenuation of mitogen-activated protein kinase (MAPK) and c-jun N-terminal kinase signaling. Furthermore, we showed that Lnk−/− BMMCs displayed increased SCF-dependent migration compared with wild-type cells, revealing a novel Lnk-mediated inhibitory function. This correlated with enhanced Rac and p38 MAPK activation. Finally, we found that Lnk domains and carboxy-terminal tyrosine contribute differently to inhibition of in vitro expansion of hematopoietic progenitors. Altogether, our results demonstrate that Lnk, through its binding to Kit tyrosine 567, negatively modulates specific SCF-dependent signaling pathways involved in the proliferation and migration of primary hematopoietic cells.
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11
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Li M, Li Z, Morris DL, Rui L. Identification of SH2B2beta as an inhibitor for SH2B1- and SH2B2alpha-promoted Janus kinase-2 activation and insulin signaling. Endocrinology 2007; 148:1615-21. [PMID: 17204555 PMCID: PMC4710543 DOI: 10.1210/en.2006-1010] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The SH2B family has three members (SH2B1, SH2B2, and SH2B3) that contain conserved dimerization (DD), pleckstrin homology, and SH2 domains. The DD domain mediates the formation of homo- and heterodimers between members of the SH2B family. The SH2 domain of SH2B1 (previously named SH2-B) or SH2B2 (previously named APS) binds to phosphorylated tyrosines in a variety of tyrosine kinases, including Janus kinase-2 (JAK2) and the insulin receptor, thereby promoting the activation of JAK2 or the insulin receptor, respectively. JAK2 binds to various members of the cytokine receptor family, including receptors for GH and leptin, to mediate cytokine responses. In mice, SH2B1 regulates energy and glucose homeostasis by enhancing leptin and insulin sensitivity. In this work, we identify SH2B2beta as a new isoform of SH2B2 (designated as SH2B2alpha) derived from the SH2B2 gene by alternative mRNA splicing. SH2B2beta has a DD and pleckstrin homology domain but lacks a SH2 domain. SH2B2beta bound to both SH2B1 and SH2B2alpha, as demonstrated by both the interaction of glutathione S-transferase-SH2B2beta fusion protein with SH2B1 or SH2B2alpha in vitro and coimmunoprecipitation of SH2B2beta with SH2B1 or SH2B2alpha in intact cells. SH2B2beta markedly attenuated the ability of SH2B1 to promote JAK2 activation and subsequent tyrosine phosphorylation of insulin receptor substrate-1 by JAK2. SH2B2beta also significantly inhibited SH2B1- or SH2B2alpha-promoted insulin signaling, including insulin-stimulated tyrosine phosphorylation of insulin receptor substrate-1. These data suggest that SH2B2beta is an endogenous inhibitor of SH2B1 and/or SH2B2alpha, negatively regulating insulin signaling and/or JAK2-mediated cellular responses.
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Affiliation(s)
- Minghua Li
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0622, USA
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12
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Liu BA, Jablonowski K, Raina M, Arcé M, Pawson T, Nash PD. The human and mouse complement of SH2 domain proteins-establishing the boundaries of phosphotyrosine signaling. Mol Cell 2006; 22:851-868. [PMID: 16793553 DOI: 10.1016/j.molcel.2006.06.001] [Citation(s) in RCA: 220] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 05/19/2006] [Accepted: 06/02/2006] [Indexed: 01/07/2023]
Abstract
SH2 domains are interaction modules uniquely dedicated to the recognition of phosphotyrosine sites and are embedded in proteins that couple protein-tyrosine kinases to intracellular signaling pathways. Here, we report a comprehensive bioinformatics, structural, and functional view of the human and mouse complement of SH2 domain proteins. This information delimits the set of SH2-containing effectors available for PTK signaling and will facilitate the systems-level analysis of pTyr-dependent protein-protein interactions and PTK-mediated signal transduction. The domain-based architecture of SH2-containing proteins is of more general relevance for understanding the large family of protein interaction domains and the modular organization of the majority of human proteins.
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Affiliation(s)
- Bernard A Liu
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637
| | - Karl Jablonowski
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637
| | - Monica Raina
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto M5G 1X5, Canada
| | - Michael Arcé
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637
| | - Tony Pawson
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto M5G 1X5, Canada.
| | - Piers D Nash
- Ben May Institute for Cancer Research and the Committee on Cancer Biology, The University of Chicago, Chicago, Illinois 60637.
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Barrès R, Grémeaux T, Gual P, Gonzalez T, Gugenheim J, Tran A, Le Marchand-Brustel Y, Tanti JF. Enigma interacts with adaptor protein with PH and SH2 domains to control insulin-induced actin cytoskeleton remodeling and glucose transporter 4 translocation. Mol Endocrinol 2006; 20:2864-75. [PMID: 16803868 PMCID: PMC1892539 DOI: 10.1210/me.2005-0455] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
APS (adaptor protein with PH and SH2 domains) initiates a phosphatidylinositol 3-kinase-independent pathway involved in insulin-stimulated glucose transport. We recently identified Enigma, a PDZ and LIM domain-containing protein, as a partner of APS and showed that APS-Enigma complex plays a critical role in actin cytoskeleton organization in fibroblastic cells. Because actin rearrangement is important for insulin-induced glucose transporter 4 (Glut 4) translocation, we studied the potential involvement of Enigma in insulin-induced glucose transport in 3T3-L1 adipocytes. Enigma mRNA was expressed in differentiated adipocytes and APS and Enigma were colocalized with cortical actin. Expression of an APS mutant unable to bind Enigma increased the insulin-induced Glut 4 translocation to the plasma membrane. By contrast, overexpression of Enigma inhibited insulin-stimulated glucose transport and Glut 4 translocation without alterations in proximal insulin signaling. This inhibitory effect was prevented with the deletion of the LIM domains of Enigma. Using time-lapse fluorescent microscopy of green fluorescent protein-actin, we demonstrated that the overexpression of Enigma altered insulin-induced actin rearrangements, whereas the expression of Enigma without its LIM domains was without effect. A physiological link between increased expression of Enigma and an alteration in insulin-induced glucose uptake was suggested by the increase in Enigma mRNA expression in adipose tissue of diabetic obese patients. Taken together, these data strongly suggest that the interaction between APS and Enigma is involved in insulin-induced Glut 4 translocation by regulating cortical actin remodeling and raise the possibility that modification of APS/Enigma ratio could participate in the alteration of insulin-induced glucose uptake in adipose tissue.
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Affiliation(s)
- Romain Barrès
- Signalisation moléculaire et obésité
INSERM : U568 IFR50Université de Nice Sophia-AntipolisFaculte de Medecine
Avenue de Valombrose
06107 NICE CEDEX 2,FR
| | - Thierry Grémeaux
- Signalisation moléculaire et obésité
INSERM : U568 IFR50Université de Nice Sophia-AntipolisFaculte de Medecine
Avenue de Valombrose
06107 NICE CEDEX 2,FR
| | - Philippe Gual
- Signalisation moléculaire et obésité
INSERM : U568 IFR50Université de Nice Sophia-AntipolisFaculte de Medecine
Avenue de Valombrose
06107 NICE CEDEX 2,FR
| | - Teresa Gonzalez
- Signalisation moléculaire et obésité
INSERM : U568 IFR50Université de Nice Sophia-AntipolisFaculte de Medecine
Avenue de Valombrose
06107 NICE CEDEX 2,FR
| | - Jean Gugenheim
- Service de Chirurgie Digestive et Centre de Transplantation Hépatique
CHU de NICE06107 Nice,FR
| | - Albert Tran
- Fédération d'Hépatologie
CHU Nice06107 Nice,FR
| | - Yannick Le Marchand-Brustel
- Signalisation moléculaire et obésité
INSERM : U568 IFR50Université de Nice Sophia-AntipolisFaculte de Medecine
Avenue de Valombrose
06107 NICE CEDEX 2,FR
| | - Jean-François Tanti
- Signalisation moléculaire et obésité
INSERM : U568 IFR50Université de Nice Sophia-AntipolisFaculte de Medecine
Avenue de Valombrose
06107 NICE CEDEX 2,FR
- * Correspondence should be adressed to: Jean-François Tanti
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14
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Takizawa H, Kubo-Akashi C, Nobuhisa I, Kwon SM, Iseki M, Taga T, Takatsu K, Takaki S. Enhanced engraftment of hematopoietic stem/progenitor cells by the transient inhibition of an adaptor protein, Lnk. Blood 2005; 107:2968-75. [PMID: 16332975 DOI: 10.1182/blood-2005-05-2138] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hematopoietic stem cells (HSCs) are the key elements responsible for maintaining blood-cell production throughout life and for lymphohematopoietic reconstitution following bone marrow (BM) transplantation. Enhancement of the engrafting potential and expansion capabilities of HSCs as well as hematopoietic progenitor cells (HPCs) has been a long-time desire as a means of reducing the risks and difficulties that accompany BM transplantation. The ability of HSCs/HPCs to reconstitute the hematopoietic system of irradiated hosts is negatively regulated by an intracellular adaptor protein, Lnk. Here we have identified the functional domains of Lnk and developed a dominant-negative (DN) Lnk mutant that inhibits the functions of Lnk endogenously expressed in the HSCs/HPCs and thereby potentiates the HSCs/HPCs for engraftment. Importantly, even transient expression of DN-Lnk in HSCs/HPCs facilitated their engraftment under nonmyeloablative conditions and fully reconstituted the lymphoid compartments of immunodeficient host animals. HPCs expressing DN-Lnk were efficiently trapped by immobilized vascular cell adhesion molecule-1 (VCAM-1) in a transwell migration assay, suggesting involvement of Lnk in the regulation of cell mobility or cellular interaction in microenvironments. Transient inhibition of Lnk or Lnk-mediated pathways could be a potent approach to augment engraftment of HSCs/HPCs without obvious side effects.
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Affiliation(s)
- Hitoshi Takizawa
- Division of Immunology, Department of Microbiology and Immunology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan
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15
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Barrès R, Gonzalez T, Le Marchand-Brustel Y, Tanti JF. The interaction between the adaptor protein APS and Enigma is involved in actin organisation. Exp Cell Res 2005; 308:334-44. [PMID: 15946664 DOI: 10.1016/j.yexcr.2005.05.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2004] [Revised: 05/03/2005] [Accepted: 05/04/2005] [Indexed: 11/17/2022]
Abstract
APS (adaptor protein with PH and SH2 domains) is an adaptor protein phosphorylated by several tyrosine kinase receptors including the insulin receptor. To identify novel binding partners of APS, we performed yeast two-hybrid screening. We identified Enigma, a PDZ and LIM domain-containing protein that was previously shown to be associated with the actin cytoskeleton. In HEK 293 cells, Enigma interacted specifically with APS, but not with the APS-related protein SH2-B. This interaction required the NPTY motif of APS and the LIM domains of Enigma. In NIH-3T3 cells that express the insulin receptor, Enigma and APS were partially co-localised with F-actin in small ruffling structures. Insulin increased the complex formation between APS and Enigma and their co-localisation in large F-actin containing ruffles. While in NIH-3T3 and HeLa cells the co-expression of both Enigma and APS did not modify the actin cytoskeleton organisation, expression of Enigma alone led to the formation of F-actin clusters. Similar alteration in actin cytoskeleton organisation was observed in cells expressing both Enigma and APS with a mutation in the NPTY motif. These results identify Enigma as a novel APS-binding protein and suggest that the APS/Enigma complex plays a critical role in actin cytoskeleton organisation.
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Affiliation(s)
- Romain Barrès
- INSERM U568 and IFR 50, Faculté de Médecine, Avenue de Valombrose, 06107 Nice Cedex 02, France
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16
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Baudler S, Baumgartl J, Hampel B, Buch T, Waisman A, Snapper CM, Krone W, Brüning JC. Insulin-like growth factor-1 controls type 2 T cell-independent B cell response. THE JOURNAL OF IMMUNOLOGY 2005; 174:5516-25. [PMID: 15843550 DOI: 10.4049/jimmunol.174.9.5516] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The IGF-1 receptor (IGF-1R) is expressed on T and B lymphocytes, and the expression of the insulin- and IGF-1-signaling machinery undergoes defined changes throughout lineage differentiation, offering a putative role for IGF-1 in the regulation of immune responses. To study the role of the IGF-1R in lymphocyte differentiation and function in vivo, we have reconstituted immunodeficient RAG2-deficient mice with IGF-1R(-/-) fetal liver cells. Despite the absence of IGF-1Rs, the development and ex vivo activation of B and T lymphocytes were unaltered in these chimeric mice. By contrast, the humoral immune response to the T cell-independent type 2 Ag 4-hydroxy-3-nitrophenyl acetyl-Ficoll was significantly reduced in mice reconstituted with IGF-1R-deficient fetal liver cells, whereas responses to the T cell-dependent Ag 4-hydroxy-3-nitrophenyl acetyl-chicken globulin were normal. Moreover, in an in vitro model of T cell-independent type 2 responses, IGF-1 promoted Ig production potently upon polyvalent membrane-IgD cross-linking. These data indicate that functional IGF-1R signaling is required for T cell-independent B cell responses in vivo, defining a novel regulatory mechanism for the immune response against bacterial polysaccharides.
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Iseki M, Kubo-Akashi C, Kwon SM, Yamaguchi A, Takatsu K, Takaki S. APS, an adaptor molecule containing PH and SH2 domains, has a negative regulatory role in B cell proliferation. Biochem Biophys Res Commun 2005; 330:1005-13. [PMID: 15809095 DOI: 10.1016/j.bbrc.2005.03.073] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2005] [Indexed: 11/18/2022]
Abstract
Adaptor molecule containing PH and SH2 domains (APS) is an intracellular adaptor protein that forms part of an adaptor family along with Lnk and SH2-B. APS transcripts are expressed in various tissues including brain, kidney, and muscle, as well as in splenic B cells but not in T cells. We investigated the functions of APS in B cell development and activation by generating APS-transgenic (APS-Tg) mice that overexpressed APS in lymphocytes. The number of B-1 cells in the peritoneal cavity was reduced in APS-Tg mice, as were B-2 cells in the spleen. B cell development in the bone marrow was partially impaired at the transition stage from proliferating large pre-B to small pre-B cells. B cell proliferation induced by B cell receptor (BCR) crosslinking but not by other B cell mitogens was also impaired in APS-Tg mice. APS co-localized with BCR complexes and filamentous actin in activated APS-Tg B cells. Thus, APS appears to play novel negative regulatory roles in BCR signaling, actin reorganization pathways, and control of compartment sizes of B-lineage cells.
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Affiliation(s)
- Masanori Iseki
- Division of Immunology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
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18
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Kubo-Akashi C, Iseki M, Kwon SM, Takizawa H, Takatsu K, Takaki S. Roles of a conserved family of adaptor proteins, Lnk, SH2-B, and APS, for mast cell development, growth, and functions: APS-deficiency causes augmented degranulation and reduced actin assembly. Biochem Biophys Res Commun 2004; 315:356-62. [PMID: 14766215 DOI: 10.1016/j.bbrc.2004.01.060] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2003] [Indexed: 01/06/2023]
Abstract
Lnk, SH2-B, and APS form a conserved adaptor protein family. All of those proteins are expressed in mast cells and their possible functions in signaling through c-Kit or FcRI have been speculated. To investigate roles of Lnk, SH2-B or APS in mast cells, we established IL-3-dependent mast cells from Ink-/-, SH2-B-/-, and APS -/- mice. IL-3-dependent growth of those cells was comparable. Proliferation or adhesion mediated by c-Kit as well as degranulation induced by cross-linking FcRI were normal in the absence of Lnk or SH2-B. In contrast, APS-deficient mast cells showed augmented degranulation after cross-linking FcRI compared to wild-type cells, while c-Kit-mediated proliferation and adhesion were kept unaffected. APS-deficient mast cells showed reduced actin assembly at steady state, although their various intracellular responses induced by cross-linking FcRI were indistinguishable compared to wild-type cells. Our results suggest potential roles of APS in controlling actin cytoskeleton and magnitude of degranulation in mast cells.
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Affiliation(s)
- Chiyomi Kubo-Akashi
- Division of Immunology, Department of Microbiology and Immunology, The Institute of Medical Science, The University of Tokyo, Shirokanedai 4-6-1, Minato-ku, Tokyo 108-8639, Japan
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