1
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Zhong T, Lei K, Lin X, Xie Z, Luo S, Zhou Z, Zhao B, Li X. Protein ubiquitination in T cell development. Front Immunol 2022; 13:941962. [PMID: 35990660 PMCID: PMC9386135 DOI: 10.3389/fimmu.2022.941962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 07/11/2022] [Indexed: 11/26/2022] Open
Abstract
As an important form of posttranslational modification, protein ubiquitination regulates a wide variety of biological processes, including different aspects of T cell development and differentiation. During T cell development, thymic seeding progenitor cells (TSPs) in the thymus undergo multistep maturation programs and checkpoints, which are critical to build a functional and tolerant immune system. Currently, a tremendous amount of research has focused on the transcriptional regulation of thymocyte development. However, in the past few years, compelling evidence has revealed that the ubiquitination system also plays a crucial role in the regulation of thymocyte developmental programs. In this review, we summarize recent findings on the molecular mechanisms and cellular pathways that regulate thymocyte ubiquitination and discuss the roles of E3 ligases and deubiquitinating enzymes (DUBs) involved in these processes. Understanding how T cell development is regulated by ubiquitination and deubiquitination will not only enhance our understanding of cell fate determination via gene regulatory networks but also provide potential novel therapeutic strategies for treating autoimmune diseases and cancer.
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Affiliation(s)
| | | | | | | | | | | | - Bin Zhao
- *Correspondence: Bin Zhao, ; Xia Li,
| | - Xia Li
- *Correspondence: Bin Zhao, ; Xia Li,
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2
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Wybenga-Groot LE, Tench AJ, Simpson CD, Germain JS, Raught B, Moran MF, McGlade CJ. SLAP2 Adaptor Binding Disrupts c-CBL Autoinhibition to Activate Ubiquitin Ligase Function. J Mol Biol 2021; 433:166880. [PMID: 33617900 DOI: 10.1016/j.jmb.2021.166880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 02/05/2021] [Accepted: 02/12/2021] [Indexed: 10/22/2022]
Abstract
CBL is a RING type E3 ubiquitin ligase that functions as a negative regulator of tyrosine kinase signaling and loss of CBL E3 function is implicated in several forms of leukemia. The Src-like adaptor proteins (SLAP/SLAP2) bind to CBL and are required for CBL-dependent downregulation of antigen receptor, cytokine receptor, and receptor tyrosine kinase signaling. Despite the established role of SLAP/SLAP2 in regulating CBL activity, the nature of the interaction and the mechanisms involved are not known. To understand the molecular basis of the interaction between SLAP/SLAP2 and CBL, we solved the crystal structure of CBL tyrosine kinase binding domain (TKBD) in complex with SLAP2. The carboxy-terminal region of SLAP2 adopts an α-helical structure which binds in a cleft between the 4H, EF-hand, and SH2 domains of the TKBD. This SLAP2 binding site is remote from the canonical TKBD phospho-tyrosine peptide binding site but overlaps with a region important for stabilizing CBL in its autoinhibited conformation. In addition, binding of SLAP2 to CBL in vitro activates the ubiquitin ligase function of autoinhibited CBL. Disruption of the CBL/SLAP2 interface through mutagenesis demonstrated a role for this protein-protein interaction in regulation of CBL E3 ligase activity in cells. Our results reveal that SLAP2 binding to a regulatory cleft of the TKBD provides an alternative mechanism for activation of CBL ubiquitin ligase function.
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Affiliation(s)
- Leanne E Wybenga-Groot
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Program in Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; SPARC BioCentre, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada.
| | - Andrea J Tench
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Program in Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada
| | - Craig D Simpson
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Program in Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Jonathan St Germain
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Brian Raught
- Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada; Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 1L7, Canada
| | - Michael F Moran
- Program in Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; SPARC BioCentre, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Department of Molecular Genetics, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - C Jane McGlade
- The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Program in Cell Biology, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Department of Medical Biophysics, University of Toronto, 610 University Avenue, Toronto, ON M5G 2M9, Canada.
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3
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Wybenga-Groot LE, McGlade CJ. Sleuthing biochemical evidence to elucidate unassigned electron density in a CBL-SLAP2 crystal complex. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2021; 77:37-46. [PMID: 33620036 DOI: 10.1107/s2053230x21000911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 01/26/2021] [Indexed: 11/10/2022]
Abstract
The Src-like adaptor proteins (SLAP/SLAP2) bind to CBL E3 ubiquitin ligase to downregulate antigen, cytokine and tyrosine kinase receptor signalling. In contrast to the phosphotyrosine-dependent binding of CBL substrates through its tyrosine kinase-binding domain (TKBD), CBL TKBD associates with the C-terminal tail of SLAP2 in a phospho-independent manner. To understand the distinct nature of this interaction, a purification protocol for SLAP2 in complex with CBL TKBD was established and the complex was crystallized. However, determination of the complex crystal structure was hindered by the apparent degradation of SLAP2 during the crystallization process, such that only the CBL TKBD residues could initially be modelled. Close examination of the CBL TKBD structure revealed a unique dimer interface that included two short segments of electron density of unknown origin. To elucidate which residues of SLAP2 to model into this unassigned density, a co-expression system was generated to test SLAP2 deletion mutants and define the minimal SLAP2 binding region. SLAP2 degradation products were also analysed by mass spectrometry. The model-building and map-generation features of the Phenix software package were employed, leading to successful modelling of the C-terminal tail of SLAP2 into the unassigned electron-density segments.
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Affiliation(s)
- Leanne E Wybenga-Groot
- SPARC BioCentre, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario M5G 0A4, Canada
| | - C Jane McGlade
- Program in Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, Ontario M5G 0A4, Canada
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4
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Mevizou R, Sirvent A, Roche S. Control of Tyrosine Kinase Signalling by Small Adaptors in Colorectal Cancer. Cancers (Basel) 2019; 11:cancers11050669. [PMID: 31091767 PMCID: PMC6562749 DOI: 10.3390/cancers11050669] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/09/2019] [Accepted: 05/12/2019] [Indexed: 01/06/2023] Open
Abstract
Tyrosine kinases (TKs) phosphorylate proteins on tyrosine residues as an intracellular signalling mechanism to coordinate intestinal epithelial cell communication and fate decision. Deregulation of their activity is ultimately connected with carcinogenesis. In colorectal cancer (CRC), it is still unclear how aberrant TK activities contribute to tumour formation because TK-encoding genes are not frequently mutated in this cancer. In vertebrates, several TKs are under the control of small adaptor proteins with potential important physiopathological roles. For instance, they can exert tumour suppressor functions in human cancer by targeting several components of the oncogenic TK signalling cascades. Here, we review how the Src-like adaptor protein (SLAP) and the suppressor of cytokine signalling (SOCS) adaptor proteins regulate the SRC and the Janus kinase (JAK) oncogenic pathways, respectively, and how their loss of function in the intestinal epithelium may influence tumour formation. We also discuss the potential therapeutic value of these adaptors in CRC.
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Affiliation(s)
- Rudy Mevizou
- CRBM, CNRS, Univ. Montpellier, "Equipe labellisée Ligue Contre le Cancer", F-34000 Montpellier, France.
| | - Audrey Sirvent
- CRBM, CNRS, Univ. Montpellier, "Equipe labellisée Ligue Contre le Cancer", F-34000 Montpellier, France.
| | - Serge Roche
- CRBM, CNRS, Univ. Montpellier, "Equipe labellisée Ligue Contre le Cancer", F-34000 Montpellier, France.
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5
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Gaud G, Roncagalli R, Chaoui K, Bernard I, Familiades J, Colacios C, Kassem S, Monsarrat B, Burlet-Schiltz O, de Peredo AG, Malissen B, Saoudi A. The costimulatory molecule CD226 signals through VAV1 to amplify TCR signals and promote IL-17 production by CD4 + T cells. Sci Signal 2018; 11:11/538/eaar3083. [PMID: 29991650 DOI: 10.1126/scisignal.aar3083] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The activation of T cells requires the guanine nucleotide exchange factor VAV1. Using mice in which a tag for affinity purification was attached to endogenous VAV1 molecules, we analyzed by quantitative mass spectrometry the signaling complex that assembles around activated VAV1. Fifty VAV1-binding partners were identified, most of which had not been previously reported to participate in VAV1 signaling. Among these was CD226, a costimulatory molecule of immune cells. Engagement of CD226 induced the tyrosine phosphorylation of VAV1 and synergized with T cell receptor (TCR) signals to specifically enhance the production of interleukin-17 (IL-17) by primary human CD4+ T cells. Moreover, co-engagement of the TCR and a risk variant of CD226 that is associated with autoimmunity (rs763361) further enhanced VAV1 activation and IL-17 production. Thus, our study reveals that a VAV1-based, synergistic cross-talk exists between the TCR and CD226 during both physiological and pathological T cell responses and provides a rational basis for targeting CD226 for the management of autoimmune diseases.
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Affiliation(s)
- Guillaume Gaud
- Centre de Physiopathologie de Toulouse Purpan, Université de Toulouse, CNRS, Inserm, Toulouse 31300, France
| | - Romain Roncagalli
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université, Inserm, CNRS, 13288 Marseille, France
| | - Karima Chaoui
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS UMR 5089, 31077 Toulouse Cedex, France
| | - Isabelle Bernard
- Centre de Physiopathologie de Toulouse Purpan, Université de Toulouse, CNRS, Inserm, Toulouse 31300, France
| | - Julien Familiades
- Centre de Physiopathologie de Toulouse Purpan, Université de Toulouse, CNRS, Inserm, Toulouse 31300, France
| | - Céline Colacios
- Centre de Physiopathologie de Toulouse Purpan, Université de Toulouse, CNRS, Inserm, Toulouse 31300, France
| | - Sahar Kassem
- Centre de Physiopathologie de Toulouse Purpan, Université de Toulouse, CNRS, Inserm, Toulouse 31300, France
| | - Bernard Monsarrat
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS UMR 5089, 31077 Toulouse Cedex, France
| | - Odile Burlet-Schiltz
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS UMR 5089, 31077 Toulouse Cedex, France
| | - Anne Gonzalez de Peredo
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS UMR 5089, 31077 Toulouse Cedex, France
| | - Bernard Malissen
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille Université, Inserm, CNRS, 13288 Marseille, France.,Centre d'Immunophénomique, Aix-Marseille Université, Inserm, CNRS, 13288 Marseille, France
| | - Abdelhadi Saoudi
- Centre de Physiopathologie de Toulouse Purpan, Université de Toulouse, CNRS, Inserm, Toulouse 31300, France.
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Naudin C, Chevalier C, Roche S. The role of small adaptor proteins in the control of oncogenic signalingr driven by tyrosine kinases in human cancer. Oncotarget 2017; 7:11033-55. [PMID: 26788993 PMCID: PMC4905456 DOI: 10.18632/oncotarget.6929] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/01/2016] [Indexed: 12/15/2022] Open
Abstract
Protein phosphorylation on tyrosine (Tyr) residues has evolved as an important mechanism to coordinate cell communication in multicellular organisms. The importance of this process has been revealed by the discovery of the prominent oncogenic properties of tyrosine kinases (TK) upon deregulation of their physiological activities, often due to protein overexpression and/or somatic mutation. Recent reports suggest that TK oncogenic signaling is also under the control of small adaptor proteins. These cytosolic proteins lack intrinsic catalytic activity and signal by linking two functional members of a catalytic pathway. While most adaptors display positive regulatory functions, a small group of this family exerts negative regulatory functions by targeting several components of the TK signaling cascade. Here, we review how these less studied adaptor proteins negatively control TK activities and how their loss of function induces abnormal TK signaling, promoting tumor formation. We also discuss the therapeutic consequences of this novel regulatory mechanism in human oncology.
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Affiliation(s)
- Cécile Naudin
- CNRS UMR5237, University Montpellier, CRBM, Montpellier, France.,Present address: INSERM U1016, CNRS UMR8104, Institut Cochin, Paris, France
| | - Clément Chevalier
- CNRS UMR5237, University Montpellier, CRBM, Montpellier, France.,Present address: SFR Biosit (UMS CNRS 3480/US INSERM 018), MRic Photonics Platform, University Rennes, Rennes, France
| | - Serge Roche
- CNRS UMR5237, University Montpellier, CRBM, Montpellier, France.,Equipe Labellisée LIGUE 2014, Ligue Contre le Cancer, Paris, France
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7
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SLAP displays tumour suppressor functions in colorectal cancer via destabilization of the SRC substrate EPHA2. Nat Commun 2016; 5:3159. [PMID: 24457997 DOI: 10.1038/ncomms4159] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Accepted: 12/19/2013] [Indexed: 12/11/2022] Open
Abstract
The adaptor SLAP is a negative regulator of receptor signalling in immune cells but its role in human cancer is ill defined. Here we report that SLAP is abundantly expressed in healthy epithelial intestine but strongly downregulated in 50% of colorectal cancer. SLAP overexpression suppresses cell tumorigenicity and invasiveness while SLAP silencing enhances these transforming properties. Mechanistically, SLAP controls SRC/EPHA2/AKT signalling via destabilization of the SRC substrate and receptor tyrosine kinase EPHA2. This activity is independent from CBL but requires SLAP SH3 interaction with the ubiquitination factor UBE4A and SLAP SH2 interaction with pTyr594-EPHA2. SRC phosphorylates EPHA2 on Tyr594, thus creating a feedback loop that promotes EPHA2 destruction and thereby self-regulates its transforming potential. SLAP silencing enhances SRC oncogenicity and sensitizes colorectal tumour cells to SRC inhibitors. Collectively, these data establish a tumour-suppressive role for SLAP in colorectal cancer and a mechanism of SRC oncogenic induction through stabilization of its cognate substrates.
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8
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Heizmann B, Sellars M, Macias-Garcia A, Chan S, Kastner P. Ikaros limits follicular B cell activation by regulating B cell receptor signaling pathways. Biochem Biophys Res Commun 2016; 470:714-720. [PMID: 26775846 DOI: 10.1016/j.bbrc.2016.01.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 01/09/2016] [Indexed: 01/14/2023]
Abstract
The Ikaros transcription factor is essential for early B cell development, but its effect on mature B cells is debated. We show that Ikaros is required to limit the response of naive splenic B cells to B cell receptor signals. Ikaros deficient follicular B cells grow larger and enter cell cycle faster after anti-IgM stimulation. Unstimulated mutant B cells show deregulation of positive and negative regulators of signal transduction at the mRNA level, and constitutive phosphorylation of ERK, p38, SYK, BTK, AKT and LYN. Stimulation results in enhanced and prolonged ERK and p38 phosphorylation, followed by hyper-proliferation. Pharmacological inhibition of ERK and p38 abrogates the increased proliferative response of Ikaros deficient cells. These results suggest that Ikaros functions as a negative regulator of follicular B cell activation.
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Affiliation(s)
- Beate Heizmann
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch, France
| | - MacLean Sellars
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch, France; David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Alejandra Macias-Garcia
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch, France; Institute for Medical Engineering and Science at MIT, Cambridge, MA 02139, USA
| | - Susan Chan
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch, France.
| | - Philippe Kastner
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM U964, CNRS UMR 7104, Université de Strasbourg, 67404 Illkirch, France; Faculté de Médecine, Université de Strasbourg, Strasbourg, France.
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9
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O'Leary CE, Lewis EL, Oliver PM. Ubiquitylation as a Rheostat for TCR Signaling: From Targeted Approaches Toward Global Profiling. Front Immunol 2015; 6:618. [PMID: 26732666 PMCID: PMC4679856 DOI: 10.3389/fimmu.2015.00618] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Accepted: 11/26/2015] [Indexed: 12/24/2022] Open
Abstract
T cell receptor (TCR) signaling must be precisely tuned to limit collateral damage and prevent reactivity to self, while still allowing robust protective immune responses that control pathogen invasion. One process that can be used to promote, modify, or terminate TCR signaling is ubiquitylation. During ubiquitylation, ubiquitin is covalently attached to target proteins through a multistep process, in which E3 ubiquitin ligases promote the formation of ubiquitin chains on selected substrates. Ubiquitylation can facilitate protein–protein interactions, direct a protein to a specific subcellular location, or initiate protein destruction. Like phosphorylation, ubiquitylation is a reversible process – deubiquitylating enzymes counteract ligase function by removing ubiquitin chains. This reversibility also allows for ubiquitin chain “editing.” Based on an emerging wealth of information from genetic loss-of-function studies showing that deregulation of ubiquitylation pathways leads to immune dysfunction, it has become increasingly apparent that the dynamic process of ubiquitylation is critical for normal immune cell function. In this review, we will describe how ubiquitylation acts as a key modulator and integrator of signaling downstream of TCR engagement. Specifically, we highlight the known roles of the substrate-specific E3 ligases and deubiquitylating enzymes in TCR signaling and T cell activation. While it is clear that ubiquitin enzymes tune T cell signaling and T cell function, elucidating the molecular mechanisms by which these proteins modulate T cells has met with significant challenges. Identifying substrates of these enzymes has been a particular challenge, and thus substrates of many E3 ligases and deubiquitylating enzymes remain largely unknown. To that end, we discuss the promise, and some practical considerations, of using proteomics-based techniques for unbiased identification of putative substrates of ubiquitin cascade proteins within primary T cells. These methods provide an exciting opportunity for further defining how TCR signals are regulated and for identifying new targets for therapeutic modulation.
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Affiliation(s)
- Claire E O'Leary
- Perelman School of Medicine, University of Pennsylvania , Philadelphia, PA , USA
| | - Emma L Lewis
- Perelman School of Medicine, University of Pennsylvania , Philadelphia, PA , USA
| | - Paula M Oliver
- Perelman School of Medicine, University of Pennsylvania , Philadelphia, PA , USA
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10
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Giotis ES, Rothwell L, Scott A, Hu T, Talbot R, Todd D, Burt DW, Glass EJ, Kaiser P. Transcriptomic Profiling of Virus-Host Cell Interactions following Chicken Anaemia Virus (CAV) Infection in an In Vivo Model. PLoS One 2015; 10:e0134866. [PMID: 26244502 PMCID: PMC4526643 DOI: 10.1371/journal.pone.0134866] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 07/14/2015] [Indexed: 12/18/2022] Open
Abstract
Chicken Anaemia Virus (CAV) is an economically important virus that targets lymphoid and erythroblastoid progenitor cells leading to immunosuppression. This study aimed to investigate the interplay between viral infection and the host's immune response to better understand the pathways that lead to CAV-induced immunosuppression. To mimic vertical transmission of CAV in the absence of maternally-derived antibody, day-old chicks were infected and their responses measured at various time-points post-infection by qRT-PCR and gene expression microarrays. The kinetics of mRNA expression levels of signature cytokines of innate and adaptive immune responses were determined by qRT-PCR. The global gene expression profiles of mock-infected (control) and CAV-infected chickens at 14 dpi were also compared using a chicken immune-related 5K microarray. Although in the thymus there was evidence of induction of an innate immune response following CAV infection, this was limited in magnitude. There was little evidence of a Th1 adaptive immune response in any lymphoid tissue, as would normally be expected in response to viral infection. Most cytokines associated with Th1, Th2 or Treg subsets were down-regulated, except IL-2, IL-13, IL-10 and IFNγ, which were all up-regulated in thymus and bone marrow. From the microarray studies, genes that exhibited significant (greater than 1.5-fold, false discovery rate <0.05) changes in expression in thymus and bone marrow on CAV infection were mainly associated with T-cell receptor signalling, immune response, transcriptional regulation, intracellular signalling and regulation of apoptosis. Expression levels of a number of adaptor proteins, such as src-like adaptor protein (SLA), a negative regulator of T-cell receptor signalling and the transcription factor Special AT-rich Binding Protein 1 (SATB1), were significantly down-regulated by CAV infection, suggesting potential roles for these genes as regulators of viral infection or cell defence. These results extend our understanding of CAV-induced immunosuppression and suggest a global immune dysregulation following CAV infection.
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Affiliation(s)
- Efstathios S. Giotis
- Agri-Food and Biosciences Institute, Belfast, United Kingdom
- Queen’s University Belfast, Belfast, United Kingdom
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Lisa Rothwell
- Institute for Animal Health, Compton, United Kingdom
| | | | - Tuanjun Hu
- Institute for Animal Health, Compton, United Kingdom
| | - Richard Talbot
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Daniel Todd
- Agri-Food and Biosciences Institute, Belfast, United Kingdom
| | - David W. Burt
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Elizabeth J. Glass
- The Roslin Institute and R(D)SVS, University of Edinburgh, Edinburgh, United Kingdom
| | - Pete Kaiser
- Institute for Animal Health, Compton, United Kingdom
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11
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The Emerging and Diverse Roles of Src-Like Adaptor Proteins in Health and Disease. Mediators Inflamm 2015; 2015:952536. [PMID: 26339145 PMCID: PMC4539169 DOI: 10.1155/2015/952536] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Revised: 01/02/2015] [Accepted: 01/05/2015] [Indexed: 12/26/2022] Open
Abstract
Although Src-like adaptor proteins (SLAP-1 and SLAP-2) were mainly studied in lymphocytes, where they act as negative regulators and provide fine control of receptor signaling, recently, several other functions of these proteins were discovered. In addition to the well-characterized immunoregulatory functions, SLAP proteins appear to have an essential role in the pathogenesis of type I hypersensitivity, osteoporosis, and numerous malignant diseases. Both adaptor proteins are expressed in a wide variety of tissues, where they have mostly inhibitory effects on multiple intracellular signaling pathways. In this review, we summarize the diverse effects of SLAP proteins.
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12
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Kazi JU, Kabir NN, Rönnstrand L. Role of SRC-like adaptor protein (SLAP) in immune and malignant cell signaling. Cell Mol Life Sci 2015; 72:2535-44. [PMID: 25772501 PMCID: PMC11113356 DOI: 10.1007/s00018-015-1882-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/01/2015] [Accepted: 03/05/2015] [Indexed: 01/05/2023]
Abstract
SRC-like adaptor protein (SLAP) is an adaptor protein structurally similar to the SRC family protein kinases. Like SRC, SLAP contains an SH3 domain followed by an SH2 domain but the kinase domain has been replaced by a unique C-terminal region. SLAP is expressed in a variety of cell types. Current studies suggest that it regulates signaling of various cell surface receptors including the B cell receptor, the T cell receptor, cytokine receptors and receptor tyrosine kinases which are important regulator of immune and cancer cell signaling. SLAP targets receptors, or its associated components, by recruiting the ubiquitin machinery and thereby destabilizing signaling. SLAP directs receptors to ubiquitination-mediated degradation and controls receptors turnover as well as signaling. Thus, SLAP appears to be an important component in regulating signal transduction required for immune and malignant cells.
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Affiliation(s)
- Julhash U. Kazi
- Division of Translational Cancer Research, Lund University, Medicon Village 404:C3, 223 63 Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
- Laboratory of Computational Biochemistry, KN Biomedical Research Institute, Barisal, Bangladesh
| | - Nuzhat N. Kabir
- Laboratory of Computational Biochemistry, KN Biomedical Research Institute, Barisal, Bangladesh
| | - Lars Rönnstrand
- Division of Translational Cancer Research, Lund University, Medicon Village 404:C3, 223 63 Lund, Sweden
- Lund Stem Cell Center, Lund University, Lund, Sweden
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13
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RTK SLAP down: the emerging role of Src-like adaptor protein as a key player in receptor tyrosine kinase signaling. Cell Signal 2014; 27:267-74. [PMID: 25446260 DOI: 10.1016/j.cellsig.2014.11.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 11/08/2014] [Indexed: 02/05/2023]
Abstract
SLAP (Src like adaptor protein) contains adjacent Src homology 3 (SH3) and Src homology 2 (SH2) domains closely related in sequence to that of cytoplasmic Src family tyrosine kinases. Expressed most abundantly in the immune system, SLAP function has been predominantly studied in the context of lymphocyte signaling, where it functions in the Cbl dependent downregulation of antigen receptor signaling. However, accumulating evidence suggests that SLAP plays a role in the regulation of a broad range of membrane receptors including members of the receptor tyrosine kinase (RTK) family. In this review we highlight the role of SLAP in the ubiquitin dependent regulation of type III RTKs PDGFR, CSF-1R, KIT and Flt3, as well as Eph family RTKs. SLAP appears to bind activated type III and Eph RTKs via a conserved autophosphorylated juxtamembrane tyrosine motif in an SH2-dependent manner, suggesting that SLAP is important in regulating RTK signaling.
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SLAP/SLAP2 prevent excessive platelet (hem)ITAM signaling in thrombosis and ischemic stroke in mice. Blood 2014; 125:185-94. [PMID: 25301707 DOI: 10.1182/blood-2014-06-580597] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Glycoprotein VI and C-type lectin-like receptor 2 are essential platelet activating receptors in hemostasis and thrombo-inflammatory disease, which signal through a (hem)immunoreceptor tyrosine-based activation motif (ITAM)-dependent pathway. The adapter molecules Src-like adapter proteins (SLAP and SLAP2) are involved in the regulation of immune cell surface expression and signaling, but their function in platelets is unknown. In this study, we show that platelets expressed both SLAP isoforms and that overexpression of either protein in a heterologous cell line almost completely inhibited glycoprotein VI and C-type lectin-like receptor 2 signaling. In mice, single deficiency of SLAP or SLAP2 had only moderate effects on platelet function, whereas double deficiency of both adapters resulted in markedly increased signal transduction, integrin activation, granule release, aggregation, procoagulant activity, and thrombin generation in response to (hem)ITAM-coupled, but not G protein-coupled, receptor activation. In vivo, constitutive SLAP/SLAP2 knockout mice displayed accelerated occlusive arterial thrombus formation and a dramatically worsened outcome after focal cerebral ischemia. This was attributed to the absence of both adapter proteins in platelets, as demonstrated by adoptive transfer of Slap(-/-)/Slap2(-/-) platelets into wild-type mice. Our results establish SLAP and SLAP2 as critical inhibitors of platelet (hem)ITAM signaling in the setting of arterial thrombosis and ischemic stroke.
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Current aspects of vitiligo genetics. Postepy Dermatol Alergol 2014; 31:247-55. [PMID: 25254010 PMCID: PMC4171675 DOI: 10.5114/pdia.2014.43497] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 05/17/2014] [Accepted: 05/27/2014] [Indexed: 12/24/2022] Open
Abstract
Vitiligo is a common acquired depigmentation disorder of the skin manifested by the presence of white macules. The disease occurs at a frequency of approximately 1–4% of the world population. Currently, the most popular theory of vitiligo development is a multifactorial hypothesis according to which genetic conditions predispose vitiligo macules to occur as a result of specific environmental factors. According to the genetic hypothesis, vitiligo inheritance is multigenic. Genetic studies conducted so far concern patients with non-segmental vitiligo. There are three basic techniques of genetic studies: candidate gene association studies, genomewide linkage studies and genome-wide association studies (GWAS). The GWAS are the “gold standard” for detecting susceptibility genes. Up to now, approximately 36 convincing non-segmental vitiligo susceptibility loci have been identified. Approximately 90% of them encode immunoregulatory proteins, while approximately 10% encode melanocyte proteins. The existence of various associations between vitiligo and other autoimmune diseases may provide new knowledge on the causes of many disorders. Examples include the inverse relationship between vitiligo and melanoma and association of vitiligo with other autoimmune diseases. The main goal of all researches is to find new, optimal therapeutic strategies for vitiligo and other autoimmune diseases.
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Moulton VR, Gillooly AR, Tsokos GC. Ubiquitination regulates expression of the serine/arginine-rich splicing factor 1 (SRSF1) in normal and systemic lupus erythematosus (SLE) T cells. J Biol Chem 2013; 289:4126-34. [PMID: 24368769 DOI: 10.1074/jbc.m113.518662] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
T cells from patients with systemic lupus erythematosus (SLE) exhibit reduced expression of the critical T cell receptor (TCR)-associated CD3ζ signaling chain and are poor producers of the vital cytokine IL-2. By oligonucleotide pulldown and mass spectrometry discovery approaches, we identified the splicing regulator serine/arginine-rich splicing factor (SRSF) 1 or splicing factor 2/alternative splicing factor (SF2/ASF) to be important in the expression of CD3ζ chain. Importantly, increases in the expression of SRSF1 rescued IL-2 production in T cells from patients with SLE. In this study, we investigated the regulation of SRSF1 expression in resting and activated human T cells. We found that T cell stimulation induced a rapid and significant increase in mRNA expression of SRSF1; however, protein expression levels did not correlate with this increase. Co-engagement of CD28 induced a similar mRNA induction and reduction in protein levels. Proteasomal but not lysosomal degradation was involved in this down-regulation as evidenced by blocking with specific inhibitors MG132 and bafilomycin, respectively. Immunoprecipitation studies showed increased ubiquitination of SRSF1 in activated T cells. Interestingly, T cells from patients with SLE showed increased ubiquitination of SRSF1 when compared with those from healthy individuals. Our results demonstrate a novel mechanism of regulation of the splicing factor SRSF1 in human T cells and a potential molecular mechanism that controls its expression in SLE.
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Affiliation(s)
- Vaishali R Moulton
- From the Division of Rheumatology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215
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Crystal structure of Src-like adaptor protein 2 reveals close association of SH3 and SH2 domains through β-sheet formation. Cell Signal 2013; 25:2702-8. [DOI: 10.1016/j.cellsig.2013.08.040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Accepted: 08/30/2013] [Indexed: 01/17/2023]
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Friend SF, Peterson LK, Treacy E, Stefanski AL, Sosinowski T, Pennock ND, Berger AJ, Winn VD, Dragone LL. The discovery of a reciprocal relationship between tyrosine-kinase signaling and cullin neddylation. PLoS One 2013; 8:e75200. [PMID: 24124476 PMCID: PMC3790728 DOI: 10.1371/journal.pone.0075200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 08/12/2013] [Indexed: 01/02/2023] Open
Abstract
While neddylation is known to activate cullin (CUL)-RING ubiquitin ligases (CRLs), its role in regulating T cell signaling is poorly understood. Using the investigational NEDD8 activating enzyme (NAE) inhibitor, MLN4924, we found that neddylation negatively regulates T cell receptor (TCR) signaling, as its inhibition increases IL-2 production, T cell proliferation and Treg development in vitro. We also discovered that loss of CUL neddylation occurs upon TCR signaling, and CRLs negatively regulate IL-2 production. Additionally, we found that tyrosine kinase signaling leads to CUL deneddylation in multiple cell types. These studies indicate that CUL neddylation is a global regulatory mechanism for tyrosine kinase signaling.
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Affiliation(s)
- Samantha F Friend
- Department of Pediatrics, University of Colorado School of Medicine, Denver, Colorado, United States of America ; Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish Health, Denver, Colorado, United States of America
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Gow CH, Guo C, Wang D, Hu Q, Zhang J. Differential involvement of E2A-corepressor interactions in distinct leukemogenic pathways. Nucleic Acids Res 2013; 42:137-52. [PMID: 24064250 PMCID: PMC3874172 DOI: 10.1093/nar/gkt855] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
E2A is a member of the E-protein family of transcription factors. Previous studies have reported context-dependent regulation of E2A-dependent transcription. For example, whereas the E2A portion of the E2A-Pbx1 leukemia fusion protein mediates robust transcriptional activation in t(1;19) acute lymphoblastic leukemia, the transcriptional activity of wild-type E2A is silenced by high levels of corepressors, such as the AML1-ETO fusion protein in t(8;21) acute myeloid leukemia and ETO-2 in hematopoietic cells. Here, we show that, unlike the HEB E-protein, the activation domain 1 (AD1) of E2A has specifically reduced corepressor interaction due to E2A-specific amino acid changes in the p300/CBP and ETO target motif. Replacing E2A-AD1 with HEB-AD1 abolished the ability of E2A-Pbx1 to activate target genes and to induce cell transformation. On the other hand, the weak E2A-AD1-corepressor interaction imposes a critical importance on another ETO-interacting domain, downstream ETO-interacting sequence (DES), for corepressor-mediated repression. Deletion of DES abrogates silencing of E2A activity by AML1-ETO in t(8;21) leukemia cells or by ETO-2 in normal hematopoietic cells. Our results reveal an E2A-specific mechanism important for its context-dependent activation and repression function, and provide the first evidence for the differential involvement of E2A-corepressor interactions in distinct leukemogenic pathways.
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Affiliation(s)
- Chien-Hung Gow
- Department of Cancer Biology, Vontz Center for Molecular Studies, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0521, USA
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SLAP deficiency increases TCR avidity leading to altered repertoire and negative selection of cognate antigen-specific CD8+ T cells. Immunol Res 2013; 55:116-24. [PMID: 22956467 DOI: 10.1007/s12026-012-8354-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
How T cell receptor (TCR) avidity influences CD8(+) T cell development and repertoire selection is not yet fully understood. To fill this gap, we utilized Src-like adaptor protein (SLAP)-deficient mice as a tool to increase TCR avidity on double positive (DP) thymocytes. We generated SLAP(-/-) mice with the transgenic MHC class I-restricted TCR (OT-1) and SLAP(-/-) Vβ5 mice, expressing only the β-chain of the TCR OT-1 transgene, to examine the effects of increased TCR surface levels on CD8(+) T cell development and repertoire selection. In comparing SLAP(-/-) OT-1 and Vβ5 mice with wild-type controls, we performed compositional analysis and assessed thymocyte signaling by measuring CD5 levels. In addition, we performed tetramer and compositional staining to measure affinity for the cognate antigen, ovalbumin (OVA) peptide, presented by MHC. Furthermore, we quantified differences in α-chain repertoire in SLAP(-/-) Vβ5 mice. We have found that SLAP(-/-) OT-1 mice have fewer CD8(+) thymocytes but have increased CD5 expression. SLAP(-/-) OT-1 mice have fewer DP thymocytes expressing Vα2, signifying increased endogenous α-chain rearrangement, and more non-OVA-specific CD8(+) splenocytes upon tetramer staining. Our data demonstrate that SLAP(-/-) Vβ5 mice also have fewer OVA-specific cells and increased Vα2 usage in the peripheral Vβ5 CD8(+) T cells that were non-OVA-specific, demonstrating differences in α-chain repertoire. These studies provide direct evidence that increased TCR avidity in DP thymocytes enhances CD8(+) T cell negative selection deleting thymocytes with specificity for cognate antigen, an antigen the mature T cells may never encounter. Collectively, these studies provide new insights into how TCR avidity during CD8(+) T cell development influences repertoire selection.
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Activation of EphA receptors mediates the recruitment of the adaptor protein Slap, contributing to the downregulation of N-methyl-D-aspartate receptors. Mol Cell Biol 2013; 33:1442-55. [PMID: 23382070 DOI: 10.1128/mcb.01618-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Regulation of the activity of N-methyl-d-aspartate receptors (NMDARs) at glutamatergic synapses is essential for certain forms of synaptic plasticity underlying learning and memory and is also associated with neurotoxicity and neurodegenerative diseases. In this report, we investigate the role of Src-like adaptor protein (Slap) in NMDA receptor signaling. We present data showing that in dissociated neuronal cultures, activation of ephrin (Eph) receptors by chimeric preclustered eph-Fc ligands leads to recruitment of Slap and NMDA receptors at the sites of Eph receptor activation. Interestingly, our data suggest that prolonged activation of EphA receptors is as efficient in recruiting Slap and NMDA receptors as prolonged activation of EphB receptors. Using established heterologous systems, we examined whether Slap is an integral part of NMDA receptor signaling. Our results showed that Slap does not alter baseline activity of NMDA receptors and does not affect Src-dependent potentiation of NMDA receptor currents in Xenopus oocytes. We also demonstrate that Slap reduces excitotoxic cell death triggered by activation of NMDARs in HEK293 cells. Finally, we present evidence showing reduced levels of NMDA receptors in the presence of Slap occurring in an activity-dependent manner, suggesting that Slap is part of a mechanism that homeostatically modulates the levels of NMDA receptors.
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Savino MT, Ulivieri C, Emmi G, Prisco D, De Falco G, Ortensi B, Beccastrini E, Emmi L, Pelicci G, D'Elios MM, Baldari CT. The Shc family protein adaptor, Rai, acts as a negative regulator of Th17 and Th1 cell development. J Leukoc Biol 2013; 93:549-59. [PMID: 23345394 DOI: 10.1189/jlb.0712331] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Rai, a Shc adapter family member, acts as a negative regulator of antigen receptor signaling in T and B cells. Rai(-/-) mice develop lupus-like autoimmunity associated to the spontaneous activation of self-reactive lymphocytes. Here, we have addressed the potential role of Rai in the development of the proinflammatory Th1 and Th17 subsets, which are centrally implicated in the pathogenesis of a number of autoimmune diseases, including lupus. We show that Rai(-/-) mice display a spontaneous Th1/Th17 bias. In vitro polarization experiments on naive and effector/memory CD4(+) T cells demonstrate that Rai(-/-) favors the development and expansion of Th17 but not Th1 cells, indicating that Rai modulates TCR signaling to antagonize the pathways driving naive CD4(+) T cell differentiation to the Th17 lineage, while indirectly limiting Th1 cell development in vivo. Th1 and Th17 cell infiltrates were found in the kidneys of Rai(-/-) mice, providing evidence that Rai(-/-) contributes to the development of lupus nephritis, not only by enhancing lymphocyte activation but also by promoting the development and expansion of proinflammatory effector T cells. Interestingly, T cells from SLE patients were found to have a defect in Rai expression, suggesting a role for Rai in disease pathogenesis.
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Kazi JU, Agarwal S, Sun J, Bracco E, Rönnstrand L. Src-Like Adaptor Protein (SLAP) differentially regulates normal and oncogenic c-Kit signaling. J Cell Sci 2013; 127:653-62. [DOI: 10.1242/jcs.140590] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The Src-Like Adaptor Protein (SLAP) is an adaptor protein sharing considerable structural homology with Src. SLAP is expressed in variety of cells regulating receptor tyrosine kinase signaling by direct association. In this report, we show that SLAP associates with both wild-type and oncogenic c-Kit (c-Kit-D816V). The association involves SLAP SH2 domain and receptor phosphotyrosine residues different from those mediating Src interaction. Association of SLAP triggers c-Kit ubiquitination which, in turn, is followed by receptor degradation. Although SLAP depletion potentiates c-Kit downstream signaling by stabilizing the receptor, it remains non-functional in c-Kit-D816V signaling. Ligand-stimulated c-Kit or c-Kit-D816V did not alter membrane localization of SLAP. Interestingly oncogenic c-Kit-D816V, but not wild-type c-Kit, phosphorylates SLAP on Y120, Y258 and Y273 residues. Physical interaction between c-Kit-D816V and SLAP is mandatory for the phosphorylation to take place. Although tyrosine phosphorylated SLAP does not affect c-Kit-D816V signaling, mutation of these tyrosine sites to phenylalanine can restore SLAP activity. Taken together the data demonstrate that SLAP negatively regulates wild-type c-Kit signaling, but not its oncogenic counterpart, indicating a possible mechanism by which the oncogenic c-Kit bypasses the normal cellular negative feedback control.
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Kazi JU, Rönnstrand L. Src-Like adaptor protein (SLAP) binds to the receptor tyrosine kinase Flt3 and modulates receptor stability and downstream signaling. PLoS One 2012; 7:e53509. [PMID: 23300935 PMCID: PMC3534055 DOI: 10.1371/journal.pone.0053509] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 11/29/2012] [Indexed: 12/23/2022] Open
Abstract
Fms-like tyrosine kinase 3 (Flt3) is an important growth factor receptor in hematopoiesis. Gain-of-function mutations of the receptor contribute to the transformation of acute myeloid leukemia (AML). Src-like adaptor protein (SLAP) is an interaction partner of the E3 ubiquitin ligase Cbl that can regulate receptor tyrosine kinases-mediated signal transduction. In this study, we analyzed the role of SLAP in signal transduction downstream of the type III receptor tyrosine kinase Flt3. The results show that upon ligand stimulation SLAP stably associates with Flt3 through multiple phosphotyrosine residues in Flt3. SLAP constitutively interacts with oncogenic Flt3-ITD and co-localizes with Flt3 near the cell membrane. This association initiates Cbl-dependent receptor ubiquitination and degradation. Depletion of SLAP expression by shRNA in Flt3-transfected Ba/F3 cells resulted in a weaker activation of FL-induced PI3K-Akt and MAPK signaling. Meta-analysis of microarray data from patient samples suggests that SLAP mRNA is differentially expressed in different cancers and its expression was significantly increased in patients carrying the Flt3-ITD mutation. Thus, our data suggest a novel role of SLAP in different cancers and in modulation of receptor tyrosine kinase signaling apart from its conventional role in regulation of receptor stability.
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Affiliation(s)
- Julhash U. Kazi
- Experimental Clinical Chemistry, Wallenberg Laboratory, Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
| | - Lars Rönnstrand
- Experimental Clinical Chemistry, Wallenberg Laboratory, Department of Laboratory Medicine, Lund University, Skåne University Hospital, Malmö, Sweden
- * E-mail:
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Czimmerer Z, Varga T, Poliska S, Nemet I, Szanto A, Nagy L. Identification of novel markers of alternative activation and potential endogenous PPARγ ligand production mechanisms in human IL-4 stimulated differentiating macrophages. Immunobiology 2012; 217:1301-14. [PMID: 22954708 DOI: 10.1016/j.imbio.2012.08.270] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 07/30/2012] [Accepted: 08/02/2012] [Indexed: 01/28/2023]
Affiliation(s)
- Zsolt Czimmerer
- Department of Biochemistry and Molecular Biology, Research Center for Molecular Medicine, Medical and Health Science Center, University of Debrecen, Life Science Building, Egyetem ter 1, Debrecen H-4012, Hungary
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Érsek B, Molnár V, Balogh A, Matkó J, Cope AP, Buzás EI, Falus A, Nagy G. CD3ζ-chain expression of human T lymphocytes is regulated by TNF via Src-like adaptor protein-dependent proteasomal degradation. THE JOURNAL OF IMMUNOLOGY 2012; 189:1602-10. [PMID: 22798681 DOI: 10.4049/jimmunol.1102365] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Decreased expression of the TCR ζ-chain has been reported in several autoimmune, inflammatory, and malignant diseases, suggesting that ζ-chain downregulation is common at sites of chronic inflammation. Although ζ-chain is critically important in T lymphocyte activation, the mechanism of the decreased ζ-chain expression is less clear. Src-like adaptor protein (SLAP) is a master regulator of T cell activation; previous data have reported that SLAP regulates immunoreceptor signaling. We have examined the mechanism and the functional consequences of CD3 ζ-chain downregulation. TNF treatment of human T lymphocytes (15-40 ng/ml) selectively downregulates CD3 ζ-chain expression in a dose-dependent manner (p < 0.05) and decreases activation-induced IL-2 expression (p < 0.01). Although blocking of the lysosomal compartment fails to restore TNF-induced CD3 ζ-chain downregulation, inhibition of the proteasome prevented the effect of TNF. Both SLAP expression and the colocalization of SLAP with CD3 ζ-chain was enhanced by TNF treatment (p < 0.05 and p < 0.01, respectively), whereas TNF-induced ζ-chain downregulation was inhibited by gene silencing of SLAP with small interfering RNA. SLAP levels of the CD4(+) T lymphocytes isolated from patients with rheumatoid arthritis were more than 2-fold higher than that of the healthy donors' (p < 0.05); moreover, TNF treatment did not alter the SLAP expression of the CD4(+) cells of anti-TNF therapy-treated patients. Our present data suggest that TNF modulates T cell activation during inflammatory processes by regulating the amount of CD3 ζ-chain expression via a SLAP-dependent mechanism. These data provide evidence for SLAP-dependent regulation of CD3 ζ-chain in the fine control of TCR signaling.
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Affiliation(s)
- Barbara Érsek
- Department of Genetics, Cell, and Immunobiology, Faculty of Medicine, Semmelweis University, 1089 Budapest, Hungary
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Parakalan R, Jiang B, Nimmi B, Janani M, Jayapal M, Lu J, Tay SSW, Ling EA, Dheen ST. Transcriptome analysis of amoeboid and ramified microglia isolated from the corpus callosum of rat brain. BMC Neurosci 2012; 13:64. [PMID: 22697290 PMCID: PMC3441342 DOI: 10.1186/1471-2202-13-64] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Accepted: 05/16/2012] [Indexed: 02/03/2023] Open
Abstract
Background Microglia, the resident immune cells of the central nervous system (CNS), have two distinct phenotypes in the developing brain: amoeboid form, known to be amoeboid microglial cells (AMC) and ramified form, known to be ramified microglial cells (RMC). The AMC are characterized by being proliferative, phagocytic and migratory whereas the RMC are quiescent and exhibit a slow turnover rate. The AMC transform into RMC with advancing age, and this transformation is indicative of the gradual shift in the microglial functions. Both AMC and RMC respond to CNS inflammation, and they become hypertrophic when activated by trauma, infection or neurodegenerative stimuli. The molecular mechanisms and functional significance of morphological transformation of microglia during normal development and in disease conditions is not clear. It is hypothesized that AMC and RMC are functionally regulated by a specific set of genes encoding various signaling molecules and transcription factors. Results To address this, we carried out cDNA microarray analysis using lectin-labeled AMC and RMC isolated from frozen tissue sections of the corpus callosum of 5-day and 4-week old rat brain respectively, by laser capture microdissection. The global gene expression profiles of both microglial phenotypes were compared and the differentially expressed genes in AMC and RMC were clustered based on their functional annotations. This genome wide comparative analysis identified genes that are specific to AMC and RMC. Conclusions The novel and specific molecules identified from the trancriptome explains the quiescent state functioning of microglia in its two distinct morphological states.
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Affiliation(s)
- Rangarajan Parakalan
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Blk MD10, 4 Medical Drive, Singapore, 117597, Singapore
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Jin Y, Birlea SA, Fain PR, Ferrara TM, Ben S, Riccardi SL, Cole JB, Gowan K, Holland PJ, Bennett DC, Luiten RM, Wolkerstorfer A, van der Veen JPW, Hartmann A, Eichner S, Schuler G, van Geel N, Lambert J, Kemp EH, Gawkrodger DJ, Weetman AP, Taïeb A, Jouary T, Ezzedine K, Wallace MR, McCormack WT, Picardo M, Leone G, Overbeck A, Silverberg NB, Spritz RA. Genome-wide association analyses identify 13 new susceptibility loci for generalized vitiligo. Nat Genet 2012; 44:676-80. [PMID: 22561518 PMCID: PMC3366044 DOI: 10.1038/ng.2272] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 04/11/2012] [Indexed: 12/15/2022]
Abstract
In previous linkage and genome-wide association studies we identified 17 susceptibility loci for generalized vitiligo. By a second genome-wide association study, meta-analysis, and independent replication study, we have now identified 13 additional vitiligo-associated loci, including OCA2-HERC2, a region of 16q24.3 containing MC1R, a region of chromosome 11q21 near TYR, several immunoregulatory loci including IFIH1, CD80, CLNK, BACH2, SLA, CASP7, CD44, IKZF4, SH2B3, and a region of 22q13.2 where the causal gene remains uncertain. Functional pathway analysis shows that most vitiligo susceptibility loci encode immunoregulatory proteins or melanocyte components that likely mediate immune targeting and genetic relationships among vitiligo, malignant melanoma, and normal variation of eye, skin, and hair color.
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Affiliation(s)
- Ying Jin
- Human Medical Genetics Program, University of Colorado School of Medicine, Aurora, Colorado, USA
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Ferro M, Savino MT, Ortensi B, Finetti F, Genovese L, Masi G, Ulivieri C, Benati D, Pelicci G, Baldari CT. The Shc family protein adaptor, Rai, negatively regulates T cell antigen receptor signaling by inhibiting ZAP-70 recruitment and activation. PLoS One 2011; 6:e29899. [PMID: 22242145 PMCID: PMC3248456 DOI: 10.1371/journal.pone.0029899] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 12/08/2011] [Indexed: 12/16/2022] Open
Abstract
Rai/ShcC is a member of the Shc family of protein adaptors expressed with the highest abundance in the central nervous system, where it exerts a protective function by coupling neurotrophic receptors to the PI3K/Akt survival pathway. Rai is also expressed, albeit at lower levels, in other cell types, including T and B lymphocytes. We have previously reported that in these cells Rai attenuates antigen receptor signaling, thereby impairing not only cell proliferation but also, opposite to neurons, cell survival. Here we have addressed the mechanism underlying the inhibitory activity of Rai on TCR signaling. We show that Rai interferes with the TCR signaling cascade one of the earliest steps –recruitment of the initiating kinase ZAP-70 to the phosphorylated subunit of the TCR/CD3 complex, which results in a generalized dampening of the downstream signaling events. The inhibitory activity of Rai is associated to its inducible recruitment to phosphorylated CD3, which occurs in the physiological signaling context of the immune synapse. Rai is moreover found as a pre-assembled complex with ZAP-70 and also constitutively interacts with the regulatory p85 subunit of PI3K, similar to neuronal cells, notwithstanding the opposite biological outcome, i.e. impairment of PI-3K/Akt activation. The data highlight the ability of Rai to establish interactions with the TCR and key signaling mediators which, either directly (e.g. by inhibiting ZAP-70 recruitment to the TCR or sequestering ZAP-70/PI3K in the cytosol) or indirectly (e.g. by promoting the recruitment of effectors responsible for signal extinction) prevent full triggering of the TCR signaling cascade.
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Affiliation(s)
- Micol Ferro
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Maria Teresa Savino
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Barbara Ortensi
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Francesca Finetti
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Luca Genovese
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Giulia Masi
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Cristina Ulivieri
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Daniela Benati
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Giuliana Pelicci
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Cosima T. Baldari
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
- Istituto Toscano Tumori, University of Siena, Siena, Italy
- * E-mail:
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Liu BA, Shah E, Jablonowski K, Stergachis A, Engelmann B, Nash PD. The SH2 domain-containing proteins in 21 species establish the provenance and scope of phosphotyrosine signaling in eukaryotes. Sci Signal 2011; 4:ra83. [PMID: 22155787 DOI: 10.1126/scisignal.2002105] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The Src homology 2 (SH2) domains are participants in metazoan signal transduction, acting as primary mediators for regulated protein-protein interactions with tyrosine-phosphorylated substrates. Here, we describe the origin and evolution of SH2 domain proteins by means of sequence analysis from 21 eukaryotic organisms from the basal unicellular eukaryotes, where SH2 domains first appeared, through the multicellular animals and increasingly complex metazoans. On the basis of our results, SH2 domains and phosphotyrosine signaling emerged in the early Unikonta, and the numbers of SH2 domains expanded in the choanoflagellate and metazoan lineages with the development of tyrosine kinases, leading to rapid elaboration of phosphotyrosine signaling in early multicellular animals. Our results also indicated that SH2 domains coevolved and the number of the domains expanded alongside protein tyrosine kinases and tyrosine phosphatases, thereby coupling phosphotyrosine signaling to downstream signaling networks. Gene duplication combined with domain gain or loss produced novel SH2-containing proteins that function within phosphotyrosine signaling, which likely have contributed to diversity and complexity in metazoans. We found that intra- and intermolecular interactions within and between SH2 domain proteins increased in prevalence along with organismal complexity and may function to generate more highly connected and robust phosphotyrosine signaling networks.
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Affiliation(s)
- Bernard A Liu
- Ben May Department for Cancer Research, University of Chicago, 929 East 57th Street, Chicago, IL 60637, USA
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31
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Martínez-Martín N, Fernández-Arenas E, Cemerski S, Delgado P, Turner M, Heuser J, Irvine DJ, Huang B, Bustelo XR, Shaw A, Alarcón B. T cell receptor internalization from the immunological synapse is mediated by TC21 and RhoG GTPase-dependent phagocytosis. Immunity 2011; 35:208-22. [PMID: 21820331 PMCID: PMC4033310 DOI: 10.1016/j.immuni.2011.06.003] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 04/13/2011] [Accepted: 06/01/2011] [Indexed: 12/31/2022]
Abstract
The immunological synapse (IS) serves a dual role for sustained T cell receptor (TCR) signaling and for TCR downregulation. TC21 (Rras2) is a RRas subfamily GTPase that constitutively associates with the TCR and is implicated in tonic TCR signaling by activating phosphatidylinositol 3-kinase. In this study, we demonstrate that TC21 both cotranslocates with the TCR to the IS and is necessary for TCR internalization from the IS through a mechanism dependent on RhoG, a small GTPase previously associated with phagocytosis. Indeed, we found that the TCR triggers T cells to phagocytose 1-6 μm beads through a TC21- and RhoG-dependent pathway. We further show that TC21 and RhoG are necessary for the TCR-promoted uptake of major histocompatibility complex (MHC) from antigen-presenting cells. Therefore, TC21 and RhoG dependence underlie the existence of a common phagocytic mechanism that drives TCR internalization from the IS together with its peptide-MHC ligand.
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Clark MR, Tanaka A, Powers SE, Veselits M. Receptors, subcellular compartments and the regulation of peripheral B cell responses: the illuminating state of anergy. Mol Immunol 2010; 48:1281-6. [PMID: 21144589 DOI: 10.1016/j.molimm.2010.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 10/13/2010] [Accepted: 10/26/2010] [Indexed: 12/22/2022]
Abstract
Signals through the B cell antigen receptor (BCR) are necessary but not sufficient for cellular activation. Co-stimulatory signals must be provided through other immune recognition receptor systems, such as MHC class II/CD40 and the toll-like receptor (TLR) 9 that can only productively acquire their ligands in the processive environment of specialized late endosomes (MHC class II containing compartment or MIIC). It has long been appreciated that the BCR, by effectively capturing complex antigens and delivering them to late endosomes, is the link between activation events on the cell surface and those dependent on late endosomes. However, it has become increasingly apparent that the BCR also directs the translocation of MHC class II and TLR9 into the MIIC and that the endocytic flow of these receptors coincides with that of the BCR. This likely ensures close apposition of receptor complexes within the MIIC and the efficient transfer of ligands from the BCR to MHC class II and TLR9. This complex orchestration of receptor endocytic movement is dependent upon the quality of signals elicited through the BCR. Failure to activate specific signaling pathways, such as occurs in anergic B cells, prevents the entry of the BCR and TLR9 into the MIIC and abrogates TLR9 activation. Like anergy, this block in endocytic trafficking is rapidly reversible. These findings indicate that cellular responsiveness can be determined by mechanisms that control the subcellular location of important immune recognition receptors.
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Affiliation(s)
- Marcus R Clark
- Section of Rheumatology, Department of Medicine and Knapp Center for Lupus and Immunological Research, University of Chicago, 5841 S. Maryland Ave, Chicago, IL 60637, USA.
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Capitani N, Lucherini OM, Baldari CT. Negative regulation of immunoreceptor signaling by protein adapters: Shc proteins join the club. FEBS Lett 2010; 584:4915-22. [DOI: 10.1016/j.febslet.2010.08.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 08/23/2010] [Accepted: 08/31/2010] [Indexed: 11/26/2022]
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34
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Veillette A. Organization of immunoreceptor signaling by adapters. Immunol Rev 2009; 232:5-6. [PMID: 19909351 DOI: 10.1111/j.1600-065x.2009.00847.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- André Veillette
- Clinical Research Institute of Montreal, Montreal, QC, Canada.
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