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Merino-Vico A, van Hamburg JP, Tas SW. B Lineage Cells in ANCA-Associated Vasculitis. Int J Mol Sci 2021; 23:387. [PMID: 35008813 PMCID: PMC8745114 DOI: 10.3390/ijms23010387] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/21/2021] [Accepted: 12/28/2021] [Indexed: 12/18/2022] Open
Abstract
Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease that affects small sized blood vessels and can lead to serious complications in the lungs and kidneys. The prominent presence of ANCA autoantibodies in this disease implicates B cells in its pathogenesis, as these are the precursors of the ANCA-producing plasma cells (PCs). Further evidence supporting the potential role of B lineage cells in vasculitis are the increased B cell cytokine levels and the dysregulated B cell populations in patients. Confirmation of the contribution of B cells to pathology arose from the beneficial effect of anti-CD20 therapy (i.e., rituximab) in AAV patients. These anti-CD20 antibodies deplete circulating B cells, which results in amelioration of disease. However, not all patients respond completely, and this treatment does not target PCs, which can maintain ANCA production. Hence, it is important to develop more specific therapies for AAV patients. Intracellular signalling pathways may be potential therapeutic targets as they can show (disease-specific) alterations in certain B lineage cells, including pathogenic B cells, and contribute to differentiation and survival of PCs. Preliminary data on the inhibition of certain signalling molecules downstream of receptors specific for B lineage cells show promising therapeutic effects. In this narrative review, B cell specific receptors and their downstream signalling molecules that may contribute to pathology in AAV are discussed, including the potential to therapeutically target these pathways.
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Affiliation(s)
- Ana Merino-Vico
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Center, Amsterdam University Medical Centers, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (A.M.-V.); (J.P.v.H.)
- Department of Experimental Immunology, Amsterdam University Medical Centers, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Jan Piet van Hamburg
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Center, Amsterdam University Medical Centers, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (A.M.-V.); (J.P.v.H.)
- Department of Experimental Immunology, Amsterdam University Medical Centers, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Sander W. Tas
- Department of Rheumatology and Clinical Immunology, Amsterdam Rheumatology and Immunology Center, Amsterdam University Medical Centers, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (A.M.-V.); (J.P.v.H.)
- Department of Experimental Immunology, Amsterdam University Medical Centers, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Jackson JT, Mulazzani E, Nutt SL, Masters SL. The role of PLCγ2 in immunological disorders, cancer, and neurodegeneration. J Biol Chem 2021; 297:100905. [PMID: 34157287 PMCID: PMC8318911 DOI: 10.1016/j.jbc.2021.100905] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 06/15/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023] Open
Abstract
Phosphatidylinositol-specific phospholipase Cγ2 (PLCγ2) is a critical signaling molecule activated downstream from a variety of cell surface receptors that contain an intracellular immunoreceptor tyrosine-based activation motif. These receptors recruit kinases such as Syk, BTK, and BLNK to phosphorylate and activate PLCγ2, which then generates 1D-myo-inositol 1,4,5-trisphosphate and diacylglycerol. These well-known second messengers are required for diverse membrane functionality including cellular proliferation, endocytosis, and calcium flux. As a result, PLCγ2 dysfunction is associated with a variety of diseases including cancer, neurodegeneration, and immune disorders. The diverse pathologies associated with PLCγ2 are exemplified by distinct genetic variants. Inherited mutations at this locus cause PLCγ2-associated antibody deficiency and immune dysregulation, in some cases with autoinflammation. Acquired mutations at this locus, which often arise as a result of BTK inhibition to treat chronic lymphocytic leukemia, result in constitutive downstream signaling and lymphocyte proliferation. Finally, a third group of PLCγ2 variants actually has a protective effect in a variety of neurodegenerative disorders, presumably by increased uptake and degradation of deleterious neurological aggregates. Therefore, manipulating PLCγ2 activity either up or down could have therapeutic benefit; however, we require a better understanding of the signaling pathways propagated by these variants before such clinical utility can be realized. Here, we review the signaling roles of PLCγ2 in hematopoietic cells to help understand the effect of mutations driving immune disorders and cancer and extrapolate from this to roles which may relate to protection against neurodegeneration.
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Affiliation(s)
- Jacob T Jackson
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Elisabeth Mulazzani
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Stephen L Nutt
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Seth L Masters
- Inflammation Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia; Immunology Laboratory, Guangzhou Institute of Paediatrics, Guangzhou Women and Children's Medical Centre, Guangzhou, Guangdong, China.
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3
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Pournia F, Dang-Lawson M, Choi K, Mo V, Lampe PD, Matsuuchi L. Identification of serine residues in the connexin43 carboxyl tail important for BCR-mediated spreading of B-lymphocytes. J Cell Sci 2020; 133:jcs237925. [PMID: 31964709 PMCID: PMC10682646 DOI: 10.1242/jcs.237925] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 12/20/2019] [Indexed: 11/20/2022] Open
Abstract
B-lymphocytes recognize antigen via B-cell antigen receptors (BCRs). This binding induces signaling, leading to B-cell activation, proliferation and differentiation. Early events of BCR signaling include reorganization of actin and membrane spreading, which facilitates increased antigen gathering. We have previously shown that the gap junction protein connexin43 (Cx43; also known as GJA1) is phosphorylated upon BCR signaling, and its carboxyl tail (CT) is important for BCR-mediated spreading. Here, specific serine residues in the Cx43 CT that are phosphorylated following BCR stimulation were identified. A chimeric protein containing the extracellular and transmembrane domains of CD8 fused to the Cx43 CT was sufficient to support cell spreading. Cx43 CT truncations showed that the region between amino acids 246-307 is necessary for B-cell spreading. Site-specific serine-to-alanine mutations (S255A, S262A, S279A and S282A) resulted in differential effects on both BCR signaling and BCR-mediated spreading. These serine residues can serve as potential binding sites for actin remodeling mediators and/or BCR signaling effectors; therefore, our results may reflect unique roles for each of these serines in terms of linking the Cx43 CT to actin remodeling.
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Affiliation(s)
- Farnaz Pournia
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - May Dang-Lawson
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Kate Choi
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Microbiology and Immunology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Victor Mo
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Paul D Lampe
- Translational Research Program, Public Health Sciences and Human Biology Divisions, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N, Seattle, WA 98109-1024, USA
| | - Linda Matsuuchi
- Cell and Developmental Biology Graduate Program, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
- Department of Zoology, Life Sciences Institute, University of British Columbia (UBC), 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
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Brodie EJ, Infantino S, Low MSY, Tarlinton DM. Lyn, Lupus, and (B) Lymphocytes, a Lesson on the Critical Balance of Kinase Signaling in Immunity. Front Immunol 2018; 9:401. [PMID: 29545808 PMCID: PMC5837976 DOI: 10.3389/fimmu.2018.00401] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/13/2018] [Indexed: 01/23/2023] Open
Abstract
Systemic lupus erythematosus (SLE) is a progressive autoimmune disease characterized by increased sensitivity to self-antigens, auto-antibody production, and systemic inflammation. B cells have been implicated in disease progression and as such represent an attractive therapeutic target. Lyn is a Src family tyrosine kinase that plays a major role in regulating signaling pathways within B cells as well as other hematopoietic cells. Its role in initiating negative signaling cascades is especially critical as exemplified by Lyn-/- mice developing an SLE-like disease with plasma cell hyperplasia, underscoring the importance of tightly regulating signaling within B cells. This review highlights recent advances in our understanding of the function of the Src family tyrosine kinase Lyn in B lymphocytes and its contribution to positive and negative signaling pathways that are dysregulated in autoimmunity.
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Affiliation(s)
- Erica J. Brodie
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Simona Infantino
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
| | - Michael S. Y. Low
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
- Immunology Division, Walter and Eliza Hall Institute of Medical Research, University of Melbourne, Parkville, VIC, Australia
- Department of Haematology, Monash Health, Monash Hospital, Clayton, VIC, Australia
| | - David M. Tarlinton
- Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia
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Unperturbed Immune Function despite Mutation of C-Terminal Tyrosines in Syk Previously Implicated in Signaling and Activity Regulation. Mol Cell Biol 2017; 37:MCB.00216-17. [PMID: 28760774 DOI: 10.1128/mcb.00216-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/26/2017] [Indexed: 11/20/2022] Open
Abstract
The nonreceptor tyrosine kinase Syk, a central regulator of immune cell differentiation and activation, is a promising drug target for treatment of leukemia and allergic and inflammatory diseases. The clinical failure of Syk inhibitors underscores the importance of understanding the regulation of Syk function and activity. A series of previous studies emphasized the importance of three C-terminal tyrosines in Syk for kinase activity regulation, as docking sites for downstream effector molecules, and for Ca2+ mobilization. Here, we investigated the roles of these C-terminal tyrosines in the mouse. Surprisingly, expression of a triple tyrosine-to-phenylalanine human Syk mutant, SYK(Y3F), was not associated with discernible signaling defects either in reconstituted DT40 cells or in B or mast cells from mice expressing SYK(Y3F) instead of wild-type Syk. Remarkably, lymphocyte differentiation, calcium mobilization, and 2,4,6-trinitrophenyl (TNP)-specific immune responses were unperturbed in SYK(Y3F) mice. These results emphasize the capacity of immune cells to compensate for specific molecular defects, likely using redundant intermolecular interactions, and highlight the importance of in vivo analyses for understanding cellular signaling mechanisms.
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Melhem M, Abu-Farha M, Antony D, Madhoun AA, Bacchelli C, Alkayal F, AlKhairi I, John S, Alomari M, Beales PL, Alsmadi O. Novel G6B gene variant causes familial autosomal recessive thrombocytopenia and anemia. Eur J Haematol 2017; 98:218-227. [PMID: 27743390 DOI: 10.1111/ejh.12819] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/07/2016] [Indexed: 12/25/2022]
Abstract
OBJECTIVE To characterize the underlying genetic and molecular defects in a consanguineous family with lifelong blood disorder manifested with thrombocytopenia (low platelets count) and anemia. METHODS Genetic linkage analysis, exome sequencing, and functional genomics were carried out to identify and characterize the defective gene. RESULTS We identified a novel truncation mutation (p.C108*) in chromosome 6 open reading frame 25 (C6orf25) gene in this family. We also showed the p.C108* mutation was responsible for destabilizing the encoded truncated G6B protein. Unlike the truncated form, wild-type G6B expression resulted in enhanced K562 differentiation into megakaryocytes and erythrocytes. C6orf25, also known as G6B, is an effector protein for the key hematopoiesis regulators, Src homology region 2 domain-containing phosphatases SHP-1 and SHP-2. CONCLUSION G6B seems to act through an autosomal recessive mode of disease transmission in this family and regarded as the gene responsible for the observed hematological disorder. This inference is well supported further by in vivo evidence where similar outcomes were reported from G6b-/- and SHP1/2 DKO mouse models.
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Affiliation(s)
- Motasem Melhem
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Mohamed Abu-Farha
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Dinu Antony
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Ashraf Al Madhoun
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Chiara Bacchelli
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Fadi Alkayal
- Pancreatic Islet Biology & Transplantation Unit, Dasman Diabetes Institute, Dasman, Kuwait
| | - Irina AlKhairi
- Biochemistry and Molecular Biology Department, Dasman Diabetes Institute, Dasman, Kuwait
| | - Sumi John
- Integrative Informatics, Dasman Diabetes Institute, Dasman, Kuwait
| | - Mohamad Alomari
- Department of Pathology, Windsor Regional Hospital, Windsor, ON, Canada
| | - Phillip L Beales
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, UK
| | - Osama Alsmadi
- Genetics and Genomics Department, Dasman Diabetes Institute, Dasman, Kuwait
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7
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Hüttl S, Kläsener K, Schweizer M, Schneppenheim J, Oberg HH, Kabelitz D, Reth M, Saftig P, Schröder B. Processing of CD74 by the Intramembrane Protease SPPL2a Is Critical for B Cell Receptor Signaling in Transitional B Cells. THE JOURNAL OF IMMUNOLOGY 2015; 195:1548-63. [PMID: 26157172 DOI: 10.4049/jimmunol.1403171] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/09/2015] [Indexed: 12/16/2022]
Abstract
The invariant chain (CD74), a chaperone in MHC class II-mediated Ag presentation, is sequentially processed by different endosomal proteases. We reported recently that clearance of the final membrane-bound N-terminal fragment (NTF) of CD74 is mediated by the intramembrane protease signal peptide peptidase-like (SPPL)2a, a process critical for B cell development. In mice, SPPL2a deficiency provokes the accumulation of this NTF in endocytic vesicles, which leads to a B cell maturation arrest at the transitional 1 stage. To define the underlying mechanism, we analyzed the impact of SPPL2a deficiency on signaling pathways involved in B cell homeostasis. We demonstrate that tonic as well as BCR-induced activation of the PI3K/Akt pathway is massively compromised in SPPL2a(-/-) B cells and identify this as major cause of the B cell maturation defect in these mice. Altered BCR trafficking induces a reduction of surface IgM in SPPL2a-deficient B cells, leading to a diminished signal transmission via the BCR and the tyrosine kinase Syk. We provide evidence that in SPPL2a(-/-) mice impaired BCR signaling is to a great extent provoked by the accumulating CD74 NTF, which can interact with the BCR and Syk, and that impaired PI3K/Akt signaling and reduced surface IgM are not directly linked processes. In line with disturbances in PI3K/Akt signaling, SPPL2a(-/-) B cells show a dysregulation of the transcription factor FOXO1, causing elevated transcription of proapoptotic genes. We conclude that SPPL2a-mediated processing of CD74 NTF is indispensable to maintain appropriate levels of tonic BCR signaling to promote B cell maturation.
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Affiliation(s)
- Susann Hüttl
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany
| | - Kathrin Kläsener
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany; Institute for Biology III, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany; Max Planck Institute for Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Michaela Schweizer
- Center for Molecular Neurobiology, University Medical Center Hamburg-Eppendorf, D-20246 Hamburg, Germany
| | - Janna Schneppenheim
- Institute of Anatomy, Christian Albrechts University of Kiel, D-24118 Kiel, Germany; and
| | - Hans-Heinrich Oberg
- Institute of Immunology, Christian Albrechts University of Kiel, D-24105 Kiel, Germany
| | - Dieter Kabelitz
- Institute of Immunology, Christian Albrechts University of Kiel, D-24105 Kiel, Germany
| | - Michael Reth
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany; Institute for Biology III, Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany; Max Planck Institute for Immunobiology and Epigenetics, D-79108 Freiburg, Germany
| | - Paul Saftig
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany
| | - Bernd Schröder
- Biochemical Institute, Christian Albrechts University of Kiel, D-24118 Kiel, Germany;
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LV WEI, DUAN QIANGLIN, WANG LEMIN, GONG ZHU, YANG FAN, SONG YANLI. Expression of B-cell-associated genes in peripheral blood mononuclear cells of patients with symptomatic pulmonary embolism. Mol Med Rep 2014; 11:2299-305. [DOI: 10.3892/mmr.2014.2978] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 10/24/2014] [Indexed: 11/06/2022] Open
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Xu Y, Huntington ND, Harder KW, Nandurkar H, Hibbs ML, Tarlinton DM. Phosphatidylinositol-3 kinase activity in B cells is negatively regulated by Lyn tyrosine kinase. Immunol Cell Biol 2012; 90:903-11. [PMID: 22777522 DOI: 10.1038/icb.2012.31] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phosphatidylinositol-3 kinase (PI3K) activity is essential for normal B-cell receptor (BCR)-mediated responses. To understand the mechanisms of PI3K regulation during B-cell activation, we performed a series of biochemical analysis on primary B cells, and found that activity of Src family tyrosine kinases (SFK) is crucial for the activation of PI3K following BCR ligation and this is regulated by the SFK Lyn. We show that the hyperresponsive phenotype of B cells lacking Lyn is predicated on significantly increased basal and inducible PI3K activity that correlates with the constitutive hypophosphorylation of PAG/Cbp (phosphoprotein associated with glycosphingolipid-enriched microdomains/Csk-binding protein), a concomitant reduction in bound Csk in Lyn(-/-) B cells and elevated levels of active Fyn. Regulating SFK activity may thus be a central mechanism by which Lyn regulates PI3K activity in B cells. This study defines the molecular connection between the BCR and PI3K and reveals this to be a point of Lyn-mediated regulation.
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Affiliation(s)
- Yuekang Xu
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Australia
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10
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Abstract
Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma, and the role of SYK in its pathogenesis is not completely understood. Using tissue microarray, we demonstrated for the first time that SYK protein is activated in 27 of 61 (44%) primary human DLBCL tissues. Among DLBCL cell lines, 7 were sensitive and 3 were resistant to a highly specific SYK inhibitor, PRT060318. In sensitive DLBCL cells, SYK inhibition blocked the G(1)-S transition and caused cell-cycle arrest. This effect was reproduced by genetic reduction of SYK using siRNA. A detailed analysis of the BCR signaling pathways revealed that the consequence of SYK inhibition on PLCγ2 and AKT, as opposed to ERK1/2, was responsible for cell-cycle arrest. Genetic knock-down of these key molecules decelerated the proliferation of lymphoma cells. In addition, BCR signaling can be blocked by PRT060318 in primary lymphoma cells. Together, these findings provide insights into cellular pathways required for lymphoma cell growth and support the rationale for considering SYK inhibition as a potentially useful therapy for DLBCL. The results further suggest the possibility of using PLCγ2 and AKT as biomarkers to predict therapeutic response in prospective clinical trials of specific SYK inhibitors.
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11
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Syk expression patterns differ among B-cell lymphomas. Leuk Res 2010; 34:e243-5. [PMID: 20378171 DOI: 10.1016/j.leukres.2010.03.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 02/09/2010] [Accepted: 03/13/2010] [Indexed: 11/20/2022]
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Kerrigan AM, Dennehy KM, Mourão-Sá D, Faro-Trindade I, Willment JA, Taylor PR, Eble JA, Reis e Sousa C, Brown GD. CLEC-2 is a phagocytic activation receptor expressed on murine peripheral blood neutrophils. THE JOURNAL OF IMMUNOLOGY 2009; 182:4150-7. [PMID: 19299712 DOI: 10.4049/jimmunol.0802808] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CLEC-2 is a member of the "dectin-1 cluster" of C-type lectin-like receptors and was originally thought to be restricted to platelets. In this study, we demonstrate that murine CLEC-2 is also expressed by peripheral blood neutrophils, but only weakly by bone marrow or elicited inflammatory neutrophils. On circulating neutrophils, CLEC-2 can mediate phagocytosis of Ab-coated beads and the production of proinflammatory cytokines, including TNF-alpha, in response to the CLEC-2 ligand, rhodocytin. CLEC-2 possesses a tyrosine-based cytoplasmic motif similar to that of dectin-1, and we show using chimeric analyses that the activities of this receptor are dependent on this tyrosine. Like dectin-1, CLEC-2 can recruit the signaling kinase Syk in myeloid cells, however, stimulation of this pathway does not induce the respiratory burst. These data therefore demonstrate that CLEC-2 expression is not restricted to platelets and that it functions as an activation receptor on neutrophils.
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Affiliation(s)
- Ann M Kerrigan
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
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13
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Hsiao FC, Tai AK, Deglon A, Sutkowski N, Longnecker R, Huber BT. EBV LMP-2A employs a novel mechanism to transactivate the HERV-K18 superantigen through its ITAM. Virology 2008; 385:261-6. [PMID: 19070345 DOI: 10.1016/j.virol.2008.11.025] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2008] [Revised: 11/12/2008] [Accepted: 11/17/2008] [Indexed: 01/31/2023]
Abstract
EBV encodes latent membrane protein (LMP)-2A that functions as a homologue of the activated BCR. We have previously shown that LMP-2A transactivates a human endogenous retrovirus, HERV-K18, in infected B-lymphocytes. The Env protein of HERV-K18 encodes a superantigen that strongly stimulates a large number of T cells. To delineate the mechanism through which LMP-2A transactivates HERV-K18 env, we tested a panel of tyrosine mutants of LMP-2A in a murine B lymphoma that stably harbors HERV-K18. Our analysis revealed that the immunoreceptor tyrosine-based activation motif (ITAM) of LMP-2A is important for HERV-K18 env transactivation. ITAM contains 2 tyrosines that initiate signaling cascades when both residues are phosphorylated. However, in our study, single-tyrosine mutants of ITAM still retained full induction of HERV-K18 env. After truncating 25 kb of genomic sequence downstream of HERV-K18, LMP-2A failed to transactivate HERV-K18 env. Thus, an LMP-2A-inducible element is located downstream of HERV-K18.
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Affiliation(s)
- Francis C Hsiao
- Department of Pathology, Tufts University School of Medicine, Boston, MA 02111, USA
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14
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Jongstra-Bilen J, Puig Cano A, Hasija M, Xiao H, Smith CIE, Cybulsky MI. Dual Functions of Bruton’s Tyrosine Kinase and Tec Kinase during Fcγ Receptor-Induced Signaling and Phagocytosis. THE JOURNAL OF IMMUNOLOGY 2008; 181:288-98. [DOI: 10.4049/jimmunol.181.1.288] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Huysamen C, Willment JA, Dennehy KM, Brown GD. CLEC9A is a novel activation C-type lectin-like receptor expressed on BDCA3+ dendritic cells and a subset of monocytes. J Biol Chem 2008; 283:16693-701. [PMID: 18408006 PMCID: PMC2562446 DOI: 10.1074/jbc.m709923200] [Citation(s) in RCA: 240] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We describe here the first characterization of CLEC9A, a group V C-type lectin-like receptor located in the “Dectin-1 cluster” of related receptors, which are encoded within the natural killer (NK)-gene complex. Expression of human CLEC9A is highly restricted in peripheral blood, being detected only on BDCA3+ dendritic cells and on a small subset of CD14+CD16- monocytes. CLEC9A is expressed at the cell surface as a glycosylated dimer and can mediate endocytosis, but not phagocytosis. CLEC9A possesses a cytoplasmic immunoreceptor tyrosine-based activation-like motif that can recruit Syk kinase, and we demonstrate, using receptor chimeras, that this receptor can induce proinflammatory cytokine production. These data indicate that CLEC9A functions as an activation receptor.
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Affiliation(s)
- Cristal Huysamen
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, 7925, South Africa
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16
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Le Roux D, Lankar D, Yuseff MI, Vascotto F, Yokozeki T, Faure-André G, Mougneau E, Glaichenhaus N, Manoury B, Bonnerot C, Lennon-Duménil AM. Syk-dependent actin dynamics regulate endocytic trafficking and processing of antigens internalized through the B-cell receptor. Mol Biol Cell 2007; 18:3451-62. [PMID: 17596518 PMCID: PMC1951757 DOI: 10.1091/mbc.e06-12-1114] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Antigen binding to the B-cell receptor (BCR) induces multiple signaling cascades that ultimately lead to B lymphocyte activation. In addition, the BCR regulates the key trafficking events that allow the antigen to reach endocytic compartments devoted to antigen processing, i.e., that are enriched for major histocompatibility factor class II (MHC II) and accessory molecules such as H2-DM. Here, we analyze the role in antigen processing and presentation of the tyrosine kinase Syk, which is activated upon BCR engagement. We show that convergence of MHC II- and H2-DM-containing compartments with the vesicles that transport BCR-uptaken antigens is impaired in cells lacking Syk activity. This defect in endocytic trafficking compromises the ability of Syk-deficient cells to form MHC II-peptide complexes from BCR-internalized antigens. Altered endocytic trafficking is associated to a failure of Syk-deficient cells to properly reorganize their actin cytoskeleton in response to BCR engagement. We propose that, by modulating the actin dynamics induced upon BCR stimulation, Syk regulates the positioning and transport of the vesicles that carry the molecules required for antigen processing and presentation.
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Affiliation(s)
- Delphine Le Roux
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
| | - Danielle Lankar
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
| | - Maria-Isabel Yuseff
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
| | - Fulvia Vascotto
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
| | - Takeaki Yokozeki
- Department of Biochemistry, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki, Japan 305-8577; and
| | - Gabrielle Faure-André
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
| | - Evelyne Mougneau
- Institut National de la Santé et de la Recherche Médicale E0344, Université de Nice-Sophia Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire, 06560 Valbonne, France
| | - Nicolas Glaichenhaus
- Institut National de la Santé et de la Recherche Médicale E0344, Université de Nice-Sophia Antipolis, Institut de Pharmacologie Moléculaire et Cellulaire, 06560 Valbonne, France
| | - Bénédicte Manoury
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
| | - Christian Bonnerot
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
| | - Ana-Maria Lennon-Duménil
- *Institut National de la Santé et de la Recherche Médicale U653, Institut Curie, 75005, Paris, France
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17
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Caballero A, Katkere B, Wen XY, Drake L, Nashar TO, Drake JR. Functional and structural requirements for the internalization of distinct BCR-ligand complexes. Eur J Immunol 2007; 36:3131-45. [PMID: 17125144 DOI: 10.1002/eji.200636447] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Antigen (Ag) binding to the BCR rapidly initiates two important events: a phosphorylation cascade that results in the production of secondary signaling intermediaries and the internalization of Ag-BCR complexes. Previous studies using anti-BCR antibodies (Ab) have suggested that BCR signaling is an essential requirement for BCR endocytosis and have further implicated lipid rafts as essential platforms for both BCR functions. However, published data from our laboratory indicate that lipid rafts and consequently raft-mediated signaling are dispensable for BCR-mediated internalization of Ag-specific BCR. Therefore, we investigated the relationship between BCR signaling and endocytosis by defining the role of early kinase signaling in the BCR-mediated internalization of a model Ag (haptenated protein). The results demonstrate that Src kinases and Syk-mediated BCR signaling are not essential for BCR-mediated Ag internalization. Moreover, by comparing Ag and Ab, it was determined that while both localize to clathrin-coated pits, the internalization of Ab-BCR complexes is more susceptible to inhibition of signaling and highly sensitive to disruption of lipid rafts and the actin cytoskeleton compared to Ag-BCR complexes. Thus, these results demonstrate that the nature of the ligand ultimately determines the functional requirements and relative contribution of lipid rafts and other membrane structures to the internalization of BCR-ligand complexes.
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Affiliation(s)
- Adriana Caballero
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, NY 12208, USA
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18
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Abstract
Signal transduction events leading to the survival, differentiation, or apoptosis of cells of the innate or adaptive immune system must be properly coordinated to ensure the normal mounting and termination of immune responses. One of the key transcription factors in immune responses is nuclear factor kappaB (NF-kappaB), which has been the focus of intense investigation over the past two decades. With the identification of the CARMA1-BCL10-MALT1 complex and ongoing progress in understanding the molecular mechanisms connecting T cell and B cell receptor proximal signals to the IkappaB kinase (IKK) complex, a cohesive model of antigen receptor (AgR)-dependent signaling to NF-kappaB activation is beginning to emerge. In this review, we provide an overview of the current state of research into the mechanisms that regulate AgR-mediated NF-kappaB transcriptional activity, with particular focus on the events leading to activation of the IKK complex.
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Affiliation(s)
- Jan Schulze-Luehrmann
- Section of Immunobiology and Department of Molecular Biophysics & Biochemistry, Yale University School of Medicine, New Haven, CT 06520, USA
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19
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Vascotto F, Le Roux D, Lankar D, Faure-André G, Vargas P, Guermonprez P, Lennon-Duménil AM. Antigen presentation by B lymphocytes: how receptor signaling directs membrane trafficking. Curr Opin Immunol 2006; 19:93-8. [PMID: 17140785 DOI: 10.1016/j.coi.2006.11.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Accepted: 11/21/2006] [Indexed: 12/16/2022]
Abstract
Antigen capture and presentation onto MHC class II molecules by B lymphocytes is mediated by their surface antigen receptor - the B-cell receptor (BCR). The BCR must therefore coordinate the transport of MHC class II- and antigen-containing vesicles for them to converge and ensure efficient processing. Recently, progress has been made in understanding which and how these vesicular transport events are molecularly linked to BCR signaling. In particular, recent studies have emphasized the key roles of membrane microdomains and the actin cytoskeleton in regulation of membrane trafficking upon BCR engagement.
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Affiliation(s)
- Fulvia Vascotto
- Unité Inserm 653, Institut Curie, 12 rue Lhomond, 75005, Paris, France
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20
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Rinaldi A, Kwee I, Taborelli M, Largo C, Uccella S, Martin V, Poretti G, Gaidano G, Calabrese G, Martinelli G, Baldini L, Pruneri G, Capella C, Zucca E, Cotter FE, Cigudosa JC, Catapano CV, Tibiletti MG, Bertoni F. Genomic and expression profiling identifies the B-cell associated tyrosine kinase Syk as a possible therapeutic target in mantle cell lymphoma. Br J Haematol 2006; 132:303-16. [PMID: 16409295 DOI: 10.1111/j.1365-2141.2005.05883.x] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Among B-cell lymphomas mantle cell lymphoma (MCL) has the worst prognosis. By using a combination of genomic and expression profiling (Affymetrix GeneChip Mapping 10k Xba131 and U133 set), we analysed 26 MCL samples to identify genes relevant to MCL pathogenesis and that could represent new therapeutic targets. Recurrent genomic deletions and gains were detected. Genes were identified as overexpressed in regions of DNA gain on 3q, 6p, 8q, 9q, 16p and 18q, including the cancer genes BCL2 and MYC. Among the transcripts with high correlation between DNA and RNA, we identified SYK, a tyrosine kinase involved in B-cell receptor signalling. SYK was amplified at DNA level, as validated by fluorescence in situ hybridisation (FISH) analysis, and overexpressed at both RNA and protein levels in the JeKo-1 cell line. Low-level amplification, with protein overexpression of Syk was demonstrated by FISH in a small subset of clinical samples. After treatment with low doses of the Syk inhibitor piceatannol, cell proliferation arrest and apoptosis were induced in the cell line overexpressing Syk, while cells expressing low levels of Syk were much less sensitive. A combination of genomic and expression profiling suggested Syk inhibition as a new therapeutic strategy to be explored in lymphomas.
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Affiliation(s)
- Andrea Rinaldi
- Laboratory of Experimental Oncology, Oncology Institute of Southern Switzerland, Bellinzona, Switzerland
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21
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Maloney M, Bishop S, Torrence G, DeLeon M. Comparison of Total Lipid Composition in Gb3‐Positive and Gb3‐Deficient Burkitt's Lymphoma Cells. J LIQ CHROMATOGR R T 2005. [DOI: 10.1080/10826070500189802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Mark Maloney
- a Department of Biology , Spelman College , Atlanta, Georgia, USA
| | - Shanita Bishop
- a Department of Biology , Spelman College , Atlanta, Georgia, USA
| | | | - Marisela DeLeon
- a Department of Biology , Spelman College , Atlanta, Georgia, USA
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22
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Weil R, Israël A. T-cell-receptor- and B-cell-receptor-mediated activation of NF-κB in lymphocytes. Curr Opin Immunol 2004; 16:374-81. [PMID: 15134788 DOI: 10.1016/j.coi.2004.03.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
B and T cells sense antigens through specific receptors, which, when activated, induce signalling cascades leading to the activation of a series of transcription factor families, such as NF-kappaB. These transcription factors control differentiation, cytokine production and proliferation, and they protect against apoptosis. Much progress has been made during the past two years in the understanding of the molecular events leading to NF-kappaB activation, but, although most of the molecules in this signalling cascade have now been identified, the detailed molecular events remain obscure; in particular regarding the molecules that specifically connect the T-cell receptor (TCR)- and B-cell receptor (BCR)-proximal adaptors and kinases to the central core of the NF-kappaB cascade, the IkappaB kinase complex. As these events are likely to be specific for both extremities of the signalling cascade (the TCR or BCR on one end, and NF-kappaB target genes on the other) they will ultimately represent the best targets to specifically manipulate this response in lymphocytes.
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Affiliation(s)
- Robert Weil
- Unité de Biologie Moléculaire de l'Expression Génique, Unité de Recherche Associée, 2582 Centre National de la Recherche Scientifique, Institut Pasteur, 25 Rue du Dr. Roux, 75724 Paris Cedex 15, France
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23
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Newbrough SA, Mocsai A, Clemens RA, Wu JN, Silverman MA, Singer AL, Lowell CA, Koretzky GA. SLP-76 regulates Fcgamma receptor and integrin signaling in neutrophils. Immunity 2003; 19:761-9. [PMID: 14614862 DOI: 10.1016/s1074-7613(03)00305-4] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
While the contribution of intracellular adaptor proteins to lymphocyte activation has been well studied, the function of these molecules in innate immune effector cells such as neutrophils has not been extensively addressed. Here we demonstrate a critical role for the adaptor molecule SH2 domain-containing leukocyte-specific phosphoprotein of 76 kDa (SLP-76) in FcgammaR and integrin signaling. Stimulation of these receptors induces tyrosine phosphorylation and cytoplasmic relocalization of SLP-76 in freshly isolated murine neutrophils. Neutrophils lacking SLP-76 demonstrate decreased FcgammaR-induced calcium flux and reactive oxygen intermediate (ROI) production in response to immune complex stimulation. More dramatically, SLP-76-/- neutrophils fail to produce ROI, spread, or activate critical downstream regulators in response to integrin ligation. These results provide genetic evidence for a critical role of SLP-76 in the regulation of neutrophil function.
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Affiliation(s)
- Sally A Newbrough
- Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
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