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Lagos J, Sagadiev S, Diaz J, Bozo JP, Guzman F, Stefani C, Zanlungo S, Acharya M, Yuseff MI. Autophagy Induced by Toll-like Receptor Ligands Regulates Antigen Extraction and Presentation by B Cells. Cells 2022; 11:cells11233883. [PMID: 36497137 PMCID: PMC9741325 DOI: 10.3390/cells11233883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022] Open
Abstract
The engagement of B cells with surface-tethered antigens triggers the formation of an immune synapse (IS), where the local secretion of lysosomes can facilitate antigen uptake. Lysosomes intersect with other intracellular processes, such as Toll-like Receptor (TLR) signaling and autophagy coordinating immune responses. However, the crosstalk between these processes and antigen presentation remains unclear. Here, we show that TLR stimulation induces autophagy in B cells and decreases their capacity to extract and present immobilized antigens. We reveal that TLR stimulation restricts lysosome repositioning to the IS by triggering autophagy-dependent degradation of GEF-H1, a Rho GTP exchange factor required for stable lysosome recruitment at the synaptic membrane. GEF-H1 degradation is not observed in B cells that lack αV integrins and are deficient in TLR-induced autophagy. Accordingly, these cells show efficient antigen extraction in the presence of TLR stimulation, confirming the role of TLR-induced autophagy in limiting antigen extraction. Overall, our results suggest that resources associated with autophagy regulate TLR and BCR-dependent functions, which can finetune antigen uptake by B cells. This work helps to understand the mechanisms by which B cells are activated by surface-tethered antigens in contexts of subjacent inflammation before antigen recognition, such as sepsis.
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Affiliation(s)
- Jonathan Lagos
- Laboratory of Immune Cell Biology, Department of Cellular and Molecular Biology, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Center of Immunology and Immunotherapies, Seattle Children’s Research Institute, Seattle, WA 98101, USA
| | - Sara Sagadiev
- Center of Immunology and Immunotherapies, Seattle Children’s Research Institute, Seattle, WA 98101, USA
| | - Jheimmy Diaz
- Laboratory of Immune Cell Biology, Department of Cellular and Molecular Biology, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Juan Pablo Bozo
- Laboratory of Immune Cell Biology, Department of Cellular and Molecular Biology, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Fanny Guzman
- Núcleo Biotecnología Curauma, Pontificia Universidad Católica de Valparaíso, Valparaíso 2373223, Chile
| | - Caroline Stefani
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
| | - Silvana Zanlungo
- Department of Gastroenterology, School of Medicine Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Mridu Acharya
- Center of Immunology and Immunotherapies, Seattle Children’s Research Institute, Seattle, WA 98101, USA
- Department of Pediatrics, University of Washington, Seattle, WA 98195, USA
| | - Maria Isabel Yuseff
- Laboratory of Immune Cell Biology, Department of Cellular and Molecular Biology, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
- Correspondence:
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2
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Ulloa R, Corrales O, Cabrera-Reyes F, Jara-Wilde J, Saez JJ, Rivas C, Lagos J, Härtel S, Quiroga C, Yuseff MI, Diaz-Muñoz J. B Cells Adapt Their Nuclear Morphology to Organize the Immune Synapse and Facilitate Antigen Extraction. Front Immunol 2022; 12:801164. [PMID: 35222354 PMCID: PMC8863768 DOI: 10.3389/fimmu.2021.801164] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/24/2021] [Indexed: 11/25/2022] Open
Abstract
Upon interaction with immobilized antigens, B cells form an immune synapse where actin remodeling and re-positioning of the microtubule-organizing center (MTOC) together with lysosomes can facilitate antigen extraction. B cells have restricted cytoplasmic space, mainly occupied by a large nucleus, yet the role of nuclear morphology in the formation of the immune synapse has not been addressed. Here we show that upon activation, B cells re-orientate and adapt the size of their nuclear groove facing the immune synapse, where the MTOC sits, and lysosomes accumulate. Silencing the nuclear envelope proteins Nesprin-1 and Sun-1 impairs nuclear reorientation towards the synapse and leads to defects in actin organization. Consequently, B cells are unable to internalize the BCR after antigen activation. Nesprin-1 and Sun-1-silenced B cells also fail to accumulate the tethering factor Exo70 at the center of the synaptic membrane and display defective lysosome positioning, impairing efficient antigen extraction at the immune synapse. Thus, changes in nuclear morphology and positioning emerge as critical regulatory steps to coordinate B cell activation.
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Affiliation(s)
- Romina Ulloa
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Oreste Corrales
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernanda Cabrera-Reyes
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge Jara-Wilde
- Laboratory for Scientific Image Analysis SCIAN-Lab, Programa de Biología Integrativa, Instituto de Ciencias Biomédicas ICBM, Facultad de Medicina, Universidad de Chile and Biomedical Neuroscience Institute BNI, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Juan José Saez
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Christopher Rivas
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jonathan Lagos
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Steffen Härtel
- Laboratory for Scientific Image Analysis SCIAN-Lab, Programa de Biología Integrativa, Instituto de Ciencias Biomédicas ICBM, Facultad de Medicina, Universidad de Chile and Biomedical Neuroscience Institute BNI, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Centro de Informática Médica y Telemedicina CIMT, Facultad de Medicina, Universidad de Chile and Centro Nacional en Sistemas de Información en Salud CENS, Santiago, Chile
| | - Clara Quiroga
- División de Enfermedades Cardiovasculares, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.,Advanced Center for Chronic Diseases (ACCDiS), Universidad de Chile and Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María-Isabel Yuseff
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jheimmy Diaz-Muñoz
- Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
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Dondi E, Sibarita JB, Varin-Blank N, Velazquez L. The adaptor protein APS modulates BCR signalling in mature B cells. Cell Signal 2020; 73:109673. [PMID: 32470518 DOI: 10.1016/j.cellsig.2020.109673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 11/19/2022]
Abstract
Activation process of mature B cell is predominantly driven by specific BCR-mediated pathways, switched on and off all through late B cell differentiation stages. Mice deficient for APS, a member of the Lnk/SH2B family of adaptor proteins, showed that this adaptor plays a BCR-mediated regulatory role in mature B cells. However, the intermediates involved in this adaptor modulating functions in B cells are still unknown. In the present study, we investigated the role of APS in regulating BCR signalling notably through cytoskeleton remodeling in mature B cells. Herein, we showed that APS function is stage specific, as it exclusively intervenes in mature B cells. Upon activation, APS colocalizes with the BCR and associates with important regulators of BCR signalling, such as Syk and Cbl kinase. Importantly, APS interferes, as a scaffold protein, with the stability of Syk kinase by recruiting Cbl. This function is mainly mediated by APS SH2 domain, which regulates BCR-evoked cell dynamics. Our findings thus reveal that APS plays a regulatory role in BCR-induced responses by specifically modulating its interacting partners, which positions APS as a relevant modulator of BCR signalling in mature B cells.
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Affiliation(s)
- Elisabetta Dondi
- INSERM, U978, UFR SMBH, Bobigny, France; Comue USPC, Labex Inflamex, Université Paris 13, UFR SMBH, Bobigny, France
| | - Jean-Baptiste Sibarita
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, Bordeaux, France; CNRS UMR, 5297 Bordeaux, France
| | - Nadine Varin-Blank
- INSERM, U978, UFR SMBH, Bobigny, France; Comue USPC, Labex Inflamex, Université Paris 13, UFR SMBH, Bobigny, France.
| | - Laura Velazquez
- INSERM, U978, UFR SMBH, Bobigny, France; Comue USPC, Labex Inflamex, Université Paris 13, UFR SMBH, Bobigny, France.
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4
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Galectin-8 Favors the Presentation of Surface-Tethered Antigens by Stabilizing the B Cell Immune Synapse. Cell Rep 2019; 25:3110-3122.e6. [PMID: 30540943 PMCID: PMC6302547 DOI: 10.1016/j.celrep.2018.11.052] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 10/03/2018] [Accepted: 11/13/2018] [Indexed: 11/21/2022] Open
Abstract
Complete activation of B cells relies on their capacity to extract tethered antigens from immune synapses by either exerting mechanical forces or promoting their proteolytic degradation through lysosome secretion. Whether antigen extraction can also be tuned by local cues originating from the lymphoid microenvironment has not been investigated. We here show that the expression of Galectin-8-a glycan-binding protein found in the extracellular milieu, which regulates interactions between cells and matrix proteins-is increased within lymph nodes under inflammatory conditions where it enhances B cell arrest phases upon antigen recognition in vivo and promotes synapse formation during BCR recognition of immobilized antigens. Galectin-8 triggers a faster recruitment and secretion of lysosomes toward the B cell-antigen contact site, resulting in efficient extraction of immobilized antigens through a proteolytic mechanism. Thus, extracellular cues can determine how B cells sense and extract tethered antigens and thereby tune B cell responses in vivo.
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5
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Sáez JJ, Diaz J, Ibañez J, Bozo JP, Cabrera Reyes F, Alamo M, Gobert FX, Obino D, Bono MR, Lennon-Duménil AM, Yeaman C, Yuseff MI. The exocyst controls lysosome secretion and antigen extraction at the immune synapse of B cells. J Cell Biol 2019; 218:2247-2264. [PMID: 31197029 PMCID: PMC6605794 DOI: 10.1083/jcb.201811131] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 04/11/2019] [Accepted: 05/22/2019] [Indexed: 02/06/2023] Open
Abstract
BCR engagement enhances microtubule stability, which triggers the mobilization of Exo70 from the centrosome to the immune synapse. BCR engagement activates GEF-H1, which promotes exocyst assembly required for the docking and secretion of lysosomes, facilitating the extraction of surface-tethered antigens. B lymphocytes capture antigens from the surface of presenting cells by forming an immune synapse. Local secretion of lysosomes, which are guided to the synaptic membrane by centrosome repositioning, can facilitate the extraction of immobilized antigens. However, the molecular basis underlying their delivery to precise domains of the plasma membrane remains elusive. Here we show that microtubule stabilization, triggered by engagement of the B cell receptor, acts as a cue to release centrosome-associated Exo70, which is redistributed to the immune synapse. This process is coupled to the recruitment and activation of GEF-H1, which is required for assembly of the exocyst complex, used to promote tethering and fusion of lysosomes at the immune synapse. B cells silenced for GEF-H1 or Exo70 display defective lysosome secretion, which results in impaired antigen extraction and presentation. Thus, centrosome repositioning coupled to changes in microtubule stability orchestrates the spatial-temporal distribution of the exocyst complex to promote polarized lysosome secretion at the immune synapse.
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Affiliation(s)
- Juan José Sáez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Jheimmy Diaz
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jorge Ibañez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Juan Pablo Bozo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Fernanda Cabrera Reyes
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Martina Alamo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - François-Xavier Gobert
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - Dorian Obino
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - María Rosa Bono
- Department of Biology, Faculty of Sciences, Universidad de Chile, Santiago, Chile
| | - Ana-María Lennon-Duménil
- INSERM U932, Institut Curie, Centre de Recherche, PSL Research University, Paris, Île-de-France, France
| | - Charles Yeaman
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA
| | - María-Isabel Yuseff
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
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6
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Abstract
Antibody/antigen binding results in immune complexes (IC) that have a variety of regulatory functions. One important feature is the enhanced host immune activation against antigen contained in the complex. ICs play important roles at several critical steps that lead to B and T cell activation, including antigen targeting/retention, facilitated antigen uptake, antigen presenting cell activation and proper balancing of positive and negative stimulatory signals. In both poultry industry and clinical health care, ICs have been used as preventive and therapeutic vaccines. With our deepening understanding of antibody biology, particularly in light of new revelations of regulatory functions of Fc receptors, mechanistically more precise engineering has spearheaded tailored use of this tool for infection control and cancer therapy. IC-based treatment and prophylaxis have been tested to different extents in HBV, HIV and influenza viral infection control and are actively examined as an alternative treatment for several forms of tumor. As a part of this book series, this chapter aims to discuss the mechanistic aspects of IC signaling and their impact on immune cells. We give samples how this old technology has been used by practitioners over the last several decades and suggest potential paths for future development of IC-based immune therapy.
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Affiliation(s)
- Yu-Mei Wen
- Key Laboratory of Molecular Virology, Shanghai Medical College, School of Basic Medical Sciences, Fudan University, Shanghai, China. .,Shanghai Medical College, Fudan University, Rm 401, Fuxing Bldg, 131 Yi Xue Yuan Rd, Shanghai, 200032, China.
| | - Yan Shi
- Department of Basic Medical Sciences, Center for Life Sciences, Institute of Immunology, Tsinghua University, Beijing, China.,Department of Microbiology, Immunology & Infectious Diseases and Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.,D301 Medical Sciences Bldg, Tsinghua University, Beijing, 00084, China
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7
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Abstract
The ability of B lymphocytes to capture external antigens (Ag) and present them as peptide fragments, loaded on major histocompatibility complex (MHC) class II molecules, to CD4+ T cells is a crucial part of the adaptive immune response. This allows for T-B cooperation, a cellular communication that is required for B cells to develop into germinal centers (GC) and form mature high affinity antibody producing cells and to further develop B cell memory. MHC class II antigen presentation by B lymphocytes is a multistep process involving (1) Recognition and capture of external Ag by B lymphocytes through their B cell receptor (BCR), (2) Ag processing, which comprises the degradation of Ag in internal compartments within the B cell and loading of the corresponding peptide fragments on MHC class II molecules, and (3) Presentation of MHCII-peptide complexes to CD4+ T cells. Here, we describe how to study the biochemical and morphological changes that occur in B lymphocytes at these three major levels.
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8
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Mapping heterogeneity of cellular mechanics by multi-harmonic atomic force microscopy. Nat Protoc 2018; 13:2200-2216. [DOI: 10.1038/s41596-018-0031-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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9
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Clarke F, Purvis HA, Sanchez-Blanco C, Gutiérrez-Martinez E, Cornish GH, Zamoyska R, Guermonprez P, Cope AP. The protein tyrosine phosphatase PTPN22 negatively regulates presentation of immune complex derived antigens. Sci Rep 2018; 8:12692. [PMID: 30139951 PMCID: PMC6107551 DOI: 10.1038/s41598-018-31179-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 08/06/2018] [Indexed: 12/11/2022] Open
Abstract
A C1858T single nucleotide polymorphism within PTPN22 (which encodes PTPN22R620W) is associated with an enhanced susceptibility to multiple autoimmune diseases including type 1 diabetes and rheumatoid arthritis. Many of the associated autoimmune diseases have an autoantibody component to their pathology. Fc receptors (FcRs) recognise autoantibodies when they bind to autoantigens and form immune complexes. After immune complex binding and receptor crosslinking, FcRs signal via Src and Syk family kinases, leading to antigen uptake, presentation and cytokine secretion. Ptpn22 encodes a protein tyrosine phosphatase that negatively regulates Src and Syk family kinases proximal to immunoreceptor signalling cascades. We therefore hypothesised that PTPN22 regulates immune complex stimulated FcR responses in dendritic cells (DCs). Bone marrow derived DCs (BMDCs) from wild type (WT) or Ptpn22-/- mice were pulsed with ovalbumin:anti-ovalbumin immune complexes (ova ICs). Co-culture with WT OT-II T cells revealed that ova IC pulsed Ptpn22-/- BMDCs have an enhanced capability to induce T cell proliferation. This was associated with an increased capability of Ptpn22-/- BMDCs to present immune complex derived antigens and to form ova IC dependent DC-T cell conjugates. These findings highlight PTPN22 as a regulator of FcR mediated responses and provide a link between the association of PTPN22R620W with autoantibody associated autoimmune diseases.
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Affiliation(s)
- Fiona Clarke
- Centre for Inflammation Biology and Cancer Immunology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, SE1 1UL, United Kingdom.
| | - Harriet A Purvis
- Centre for Inflammation Biology and Cancer Immunology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, SE1 1UL, United Kingdom
| | - Cristina Sanchez-Blanco
- Centre for Inflammation Biology and Cancer Immunology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, SE1 1UL, United Kingdom
| | - Enrique Gutiérrez-Martinez
- Centre for Inflammation Biology and Cancer Immunology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, SE1 1UL, United Kingdom
| | - Georgina H Cornish
- Centre for Inflammation Biology and Cancer Immunology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, SE1 1UL, United Kingdom
| | - Rose Zamoyska
- Institute of Immunology and Infection Research, Centre for Immunity, Infection and Evolution, University of Edinburgh, Edinburgh, EH9 3FL, United Kingdom
| | - Pierre Guermonprez
- Centre for Inflammation Biology and Cancer Immunology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, SE1 1UL, United Kingdom
| | - Andrew P Cope
- Centre for Inflammation Biology and Cancer Immunology, School of Immunology and Microbial Sciences, Faculty of Life Sciences and Medicine, King's College London, London, SE1 1UL, United Kingdom
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10
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Drake JR. The immunobiology of ubiquitin-dependent B cell receptor functions. Mol Immunol 2018; 101:146-154. [PMID: 29940407 DOI: 10.1016/j.molimm.2018.05.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 04/29/2018] [Accepted: 05/24/2018] [Indexed: 02/01/2023]
Abstract
MHC class II-restricted antigen presentation by dendritic cells is necessary for activation of naïve CD4 T cells, whereas class II-restricted antigen presentation by B lymphocytes and macrophages is important for the recruitment of CD4+ helper and regulatory T cells. Antigen presentation by B cells is also important for induction of T cell tolerance. B cells are unique among these three types of MHC class II-expressing antigen presenting cells (APC) as they constitutively express high levels of cell surface class II molecules and express a clonally restricted antigen specific receptor, the B cell receptor (BCR). Here, I review our current understanding of three major steps that underlie the processing and presentation of BCR-bound cognate antigen: (1) endocytosis of antigen-BCR (Ag-BCR) complexes, (2) Ag-BCR trafficking to intracellular antigen processing compartments and (3) generation of antigenic peptide-MHC class II complexes, with a particular focus on the role of BCR ubiquitination in each. I will highlight potential topics for future research and briefly discuss the impact of the cell biology of BCR-mediated antigen processing on the response of the B cell and T cell to the cell-cell interactions mediated by B cell-expressed peptide-class II complexes.
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Affiliation(s)
- James R Drake
- Albany Medical College, Department of Immunology and Microbial Disease, 47 New Scotland Ave., MC-151, Albany, NY 12208-3479, United States.
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11
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Systems-Based Interactome Analysis for Hematopoiesis Effect of Angelicae sinensis Radix: Regulated Network of Cell Proliferation towards Hemopoiesis. Chin J Integr Med 2018; 25:939-947. [DOI: 10.1007/s11655-018-3003-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2016] [Indexed: 10/28/2022]
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12
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Krishnamoorthy M, Wasim L, Buhari FHM, Zhao T, Mahtani T, Ho J, Kang S, Deason-Towne F, Perraud AL, Schmitz C, Treanor B. The channel-kinase TRPM7 regulates antigen gathering and internalization in B cells. Sci Signal 2018; 11:11/533/eaah6692. [PMID: 29871912 DOI: 10.1126/scisignal.aah6692] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Members of the transient receptor potential (TRP) family of ion channels are cellular sensors involved in numerous physiological and pathological processes. We identified the TRP subfamily M member 7 (TRPM7) channel-kinase as a previously uncharacterized regulator of B cell activation. We showed that TRPM7 played a critical role in the early events of B cell activation through both its ion channel and kinase functions. DT40 B cells deficient in TRPM7 or expressing a kinase-deficient mutant of TRPM7 showed defective gathering of antigen and prolonged B cell receptor (BCR) signaling. We showed that lipid metabolism was altered in TRPM7-deficient cells and in cells expressing a kinase-deficient mutant of TRPM7 and suggest that PLC-γ2 may be a target of the kinase activity of TRPM7. Primary B cells that expressed less TRPM7 or were treated with a pharmacological inhibitor of TRPM7 also displayed defective antigen gathering and increased BCR signaling. Finally, we demonstrated that blocking TRPM7 function compromised antigen internalization and presentation to T cells. These data suggest that TRPM7 controls an essential process required for B cell affinity maturation and the production of high-affinity antibodies.
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Affiliation(s)
- Mithunah Krishnamoorthy
- Department of Cell and Systems Biology, University of Toronto, 24 Harbord Street, Toronto, Ontario M5S 3G5, Canada
| | - Laabiah Wasim
- Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Fathima Hifza Mohamed Buhari
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Tiantian Zhao
- Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Trisha Mahtani
- Department of Cell and Systems Biology, University of Toronto, 24 Harbord Street, Toronto, Ontario M5S 3G5, Canada
| | - Josephine Ho
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
| | - Sohee Kang
- Department of Computer and Mathematical Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Francina Deason-Towne
- Department of Immunology and Microbiology, University of Colorado, Denver, CO 80206, USA
| | - Anne-Laure Perraud
- Department of Immunology and Microbiology, University of Colorado, Denver, CO 80206, USA
| | - Carsten Schmitz
- Department of Immunology and Microbiology, University of Colorado, Denver, CO 80206, USA.,Department of Biomedical Research, National Jewish Health, Denver, CO 80206, USA
| | - Bebhinn Treanor
- Department of Cell and Systems Biology, University of Toronto, 24 Harbord Street, Toronto, Ontario M5S 3G5, Canada. .,Department of Immunology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.,Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C 1A4, Canada
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13
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Dagher Z, Xu S, Negoro PE, Khan NS, Feldman MB, Reedy JL, Tam JM, Sykes DB, Mansour MK. Fluorescent Tracking of Yeast Division Clarifies the Essential Role of Spleen Tyrosine Kinase in the Intracellular Control of Candida glabrata in Macrophages. Front Immunol 2018; 9:1058. [PMID: 29868018 PMCID: PMC5964189 DOI: 10.3389/fimmu.2018.01058] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 04/27/2018] [Indexed: 01/07/2023] Open
Abstract
Macrophages play a critical role in the elimination of fungal pathogens. They are sensed via cell surface pattern-recognition receptors and are phagocytosed into newly formed organelles called phagosomes. Phagosomes mature through the recruitment of proteins and lysosomes, resulting in addition of proteolytic enzymes and acidification of the microenvironment. Our earlier studies demonstrated an essential role of Dectin-1-dependent activation of spleen tyrosine kinase (Syk) in the maturation of fungal containing phagosomes. The absence of Syk activity interrupted phago-lysosomal fusion resulting in arrest at an early phagosome stage. In this study, we sought to define the contribution of Syk to the control of phagocytosed live Candida glabrata in primary macrophages. To accurately measure intracellular yeast division, we designed a carboxyfluorescein succinimidyl ester (CFSE) yeast division assay in which bright fluorescent parent cells give rise to dim daughter cells. The CFSE-labeling of C. glabrata did not affect the growth rate of the yeast. Following incubation with macrophages, internalized CFSE-labeled C. glabrata were retrieved by cellular lysis, tagged using ConA-647, and the amount of residual CFSE fluorescence was assessed by flow cytometry. C. glabrata remained undivided (CFSE bright) for up to 18 h in co-culture with primary macrophages. Treatment of macrophages with R406, a specific Syk inhibitor, resulted in loss of intracellular control of C. glabrata with initiation of division within 4 h. Delayed Syk inhibition after 8 h was less effective indicating that Syk is critically required at early stages of macrophage–fungal interaction. In conclusion, we demonstrate a new method of tracking division of C. glabrata using CFSE labeling. Our results suggest that early Syk activation is essential for macrophage control of phagocytosed C. glabrata.
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Affiliation(s)
- Zeina Dagher
- Division of Infectious Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Shuying Xu
- Division of Infectious Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Paige E Negoro
- Division of Infectious Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Nida S Khan
- Division of Infectious Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States.,Biomedical Engineering and Biotechnology, University of Massachusetts Medical School, Worcester, MA, United States
| | - Michael B Feldman
- Division of Pulmonary and Critical Care, Massachusetts General Hospital, Boston, MA, United States
| | - Jennifer L Reedy
- Division of Infectious Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Jenny M Tam
- Division of Infectious Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - David B Sykes
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, United States
| | - Michael K Mansour
- Division of Infectious Disease, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
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14
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Obino D, Diaz J, Sáez JJ, Ibañez-Vega J, Sáez PJ, Alamo M, Lankar D, Yuseff MI. Vamp-7-dependent secretion at the immune synapse regulates antigen extraction and presentation in B-lymphocytes. Mol Biol Cell 2017; 28:890-897. [PMID: 28179460 PMCID: PMC5385938 DOI: 10.1091/mbc.e16-10-0722] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 11/11/2022] Open
Abstract
Recognition of surface-tethered antigens (Ags) by B-cells leads to the formation of an immune synapse that promotes Ag uptake for presentation onto MHC-II molecules. Extraction of immobilized Ags at the immune synapse of B-cells relies on the local secretion of lysosomes, which are recruited to the Ag contact site by polarization of their microtubule network. Although conserved polarity proteins have been implicated in coordinating cytoskeleton remodeling with lysosome trafficking, the cellular machinery associated with lysosomal vesicles that regulates their docking and secretion at the synaptic interface has not been defined. Here we show that the v-SNARE protein Vamp-7 is associated with Lamp-1+ lysosomal vesicles, which are recruited and docked at the center of the immune synapse of B-cells. A decrease in Vamp-7 expression does not alter lysosome transport to the synaptic interface but impairs their local secretion, a defect that compromises the ability of B-cells to extract, process, and present immobilized Ag. Thus our results reveal that B-cells rely on the SNARE protein Vamp-7 to promote the local exocytosis of lysosomes at the immune synapse, which is required for efficient Ag extraction and presentation.
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Affiliation(s)
- Dorian Obino
- INSERM, U932 Immunité et Cancer, Institut Curie, PSL Research University, 75005 Paris, France
| | - Jheimmy Diaz
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Juan José Sáez
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Jorge Ibañez-Vega
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Pablo J Sáez
- INSERM, U932 Immunité et Cancer, Institut Curie, PSL Research University, 75005 Paris, France
| | - Martina Alamo
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
| | - Danielle Lankar
- INSERM, U932 Immunité et Cancer, Institut Curie, PSL Research University, 75005 Paris, France
| | - Maria-Isabel Yuseff
- Department of Cellular and Molecular Biology, Faculty of Sciences, Pontificia Universidad Católica de Chile, Santiago 8331150, Chile
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15
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Wen YM, Mu L, Shi Y. Immunoregulatory functions of immune complexes in vaccine and therapy. EMBO Mol Med 2016; 8:1120-1133. [PMID: 27572622 PMCID: PMC5048363 DOI: 10.15252/emmm.201606593] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/01/2016] [Accepted: 08/03/2016] [Indexed: 12/15/2022] Open
Abstract
Clinical and experimental preparations of IgG/soluble antigen complexes, as well as those formed following antibody therapy in vivo, are multifaceted immune regulators. These immune complexes (ICs) have been tested in humans and animal models, mostly in forms of experimental or clinical vaccination, for at least a century. With intensified research on Fcγ receptor-mediated immune modulation, as well as with immune complex-directed antigen processing, presentation, and inflammatory responses, there are renewed interests of using ICs in vaccines and immunotherapies. Currently, IC-based immune therapy has been broadly experimented in HBV and HIV viral infection control and antitumor treatments. However, mechanistic insights of IC-based treatments are relatively recent subjects of study; strong efforts are needed to establish links to connect laboratory findings with clinical practices. This review covers the history, mechanisms, and in vivo outcomes of this safe and effective therapeutic tool, with a clear aim to bridge laboratory findings with evolving clinical applications.
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Affiliation(s)
- Yu-Mei Wen
- Key Laboratory of Molecular Medical Virology, MOE/MOH, School of Basic Medical Sciences Shanghai Medical College Fudan University, Shanghai, China
| | - Libing Mu
- Center for Life Sciences, Department of Basic Medical Sciences, Institute of Immunology Tsinghua University, Beijing, China
| | - Yan Shi
- Center for Life Sciences, Department of Basic Medical Sciences, Institute of Immunology Tsinghua University, Beijing, China Department of Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, Canada
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16
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Coffey G, Rani A, Betz A, Pak Y, Haberstock-Debic H, Pandey A, Hollenbach S, Gretler DD, Mant T, Jurcevic S, Sinha U. PRT062607 Achieves Complete Inhibition of the Spleen Tyrosine Kinase at Tolerated Exposures Following Oral Dosing in Healthy Volunteers. J Clin Pharmacol 2016; 57:194-210. [PMID: 27406873 PMCID: PMC5248591 DOI: 10.1002/jcph.794] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 12/31/2022]
Abstract
The spleen tyrosine kinase (SYK) regulates immune cell activation in response to engagement of a variety of receptors, making it an intriguing target for the treatment of inflammatory and autoimmune disorders as well as certain B‐cell malignancies. We have previously reported on the discovery and preclinical characterization of PRT062607, a potent and highly selective inhibitor of SYK that exhibits robust anti‐inflammatory activity in a variety of animal models. Here we present data from our first human studies aimed at characterizing the pharmacokinetics (PK), pharmacodynamics (PD), and safety of PRT062607 in healthy volunteers following single and multiple oral administrations. PRT062607 demonstrated a favorable PK profile and the ability to completely inhibit SYK activity in multiple whole‐blood assays. The PD half‐life in the more sensitive assays was approximately 24 hours and returned to predose levels by 72 hours. Selectivity for SYK was observed at all dose levels tested. Analysis of the PK/PD relationship indicated an IC50 of 324 nM for inhibition of B‐cell antigen receptor‐mediated B‐cell activation and 205 nM for inhibition of FcεRI‐mediated basophil degranulation. PRT062607 was safe and well tolerated across the entire range of doses. Clinical PK/PD was related to in vivo anti‐inflammatory activity of PRT062607 in the rat collagen‐induced arthritis model, which predicts that therapeutic concentrations may be safely achieved in humans for the treatment of autoimmune disease. PRT062607 has a desirable PK profile and is capable of safely, potently, and selectively suppressing SYK kinase function in humans following once‐daily oral dosing.
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Affiliation(s)
- Greg Coffey
- Portola Pharmaceuticals, Inc, South San Francisco, CA, USA
| | | | - Andreas Betz
- Portola Pharmaceuticals, Inc, South San Francisco, CA, USA
| | - Yvonne Pak
- Portola Pharmaceuticals, Inc, South San Francisco, CA, USA
| | | | - Anjali Pandey
- Portola Pharmaceuticals, Inc, South San Francisco, CA, USA
| | | | | | - Tim Mant
- Quintiles Drug Research Unit at Guy's Hospital, London, UK
| | | | - Uma Sinha
- Portola Pharmaceuticals, Inc, South San Francisco, CA, USA
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17
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Bretou M, Kumari A, Malbec O, Moreau HD, Obino D, Pierobon P, Randrian V, Sáez PJ, Lennon-Duménil AM. Dynamics of the membrane-cytoskeleton interface in MHC class II-restricted antigen presentation. Immunol Rev 2016; 272:39-51. [DOI: 10.1111/imr.12429] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Marine Bretou
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Anita Kumari
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Odile Malbec
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Hélène D. Moreau
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Dorian Obino
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Paolo Pierobon
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Violaine Randrian
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
| | - Pablo J. Sáez
- Inserm U932, Institut Curie; ANR-10-IDEX-0001-02 PSL* and ANR-11-LABX-0043; Paris France
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18
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Na BR, Kwon MS, Chae MW, Kim HR, Kim CH, Jun CD, Park ZY. Transgelin-2 in B-Cells Controls T-Cell Activation by Stabilizing T Cell - B Cell Conjugates. PLoS One 2016; 11:e0156429. [PMID: 27232882 PMCID: PMC4883795 DOI: 10.1371/journal.pone.0156429] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/14/2016] [Indexed: 01/09/2023] Open
Abstract
The immunological synapse (IS), a dynamic and organized junction between T-cells and antigen presenting cells (APCs), is critical for initiating adaptive immunity. The actin cytoskeleton plays a major role in T-cell reorganization during IS formation, and we previously reported that transgelin-2, an actin-binding protein expressed in T-cells, stabilizes cortical F-actin, promoting T-cell activation in response to antigen stimulation. Transgelin-2 is also highly expressed in B-cells, although no specific function has been reported. In this study, we found that deficiency in transgelin-2 (TAGLN2-/-) in B-cells had little effect on B-cell development and activation, as measured by the expression of CD69, MHC class II molecules, and CD80/86. Nevertheless, in B-cells, transgelin-2 accumulated in the IS during the interaction with T-cells. These results led us to hypothesize that transgelin-2 may also be involved in IS stability in B-cells, thereby influencing T-cell function. Notably, we found that transgelin-2 deficiency in B-cells reduced T-cell activation, as determined by the release of IL-2 and interferon-γ and the expression of CD69. Furthermore, the reduced T-cell activation was correlated with reduced B-cell-T-cell conjugate formation. Collectively, these results suggest that actin stability in B-cells during IS formation is critical for the initiation of adaptive T-cell immunity.
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Affiliation(s)
- Bo-Ra Na
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Min-Sung Kwon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
- World Institute of Kimchi, Gwangju, Korea
| | - Myoung-Won Chae
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Hye-Ran Kim
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Chang-Hyun Kim
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Chang-Duk Jun
- School of Life Sciences, Immune Synapse Research Center and Cell Dynamics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
- * E-mail: (CDJ); (ZYP)
| | - Zee-Yong Park
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
- * E-mail: (CDJ); (ZYP)
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19
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Sharman J, Di Paolo J. Targeting B-cell receptor signaling kinases in chronic lymphocytic leukemia: the promise of entospletinib. Ther Adv Hematol 2016; 7:157-70. [PMID: 27247756 PMCID: PMC4872176 DOI: 10.1177/2040620716636542] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The B-cell receptor signaling pathway has emerged as an important therapeutic target in chronic lymphocytic leukemia and other B-cell malignancies. Novel agents have been developed targeting the signaling enzymes spleen tyrosine kinase (SYK), Bruton’s tyrosine kinase, and phosphoinositide 3-kinase delta. This review discusses the rationale for targeting these enzymes, as well as the preclinical and clinical evidence supporting their role as therapeutic targets, with a particular focus on SYK inhibition with entospletinib.
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Affiliation(s)
- Jeff Sharman
- Willamette Valley Cancer Institute and Research Center, US Oncology Research, 3377 Riverbend Drive, Suite 500, Springfield, OR 97477, USA
| | - Julie Di Paolo
- Department of Biology, Gilead Sciences, Inc., Foster City, CA, USA
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20
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Dysfunctional BLK in common variable immunodeficiency perturbs B-cell proliferation and ability to elicit antigen-specific CD4+ T-cell help. Oncotarget 2016; 6:10759-71. [PMID: 25926555 PMCID: PMC4484417 DOI: 10.18632/oncotarget.3577] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 02/21/2015] [Indexed: 11/25/2022] Open
Abstract
Common Variable Immunodeficiency (CVID) is the most prevalent primary antibody deficiency, and characterized by defective generation of high-affinity antibodies. Patients have therefore increased risk to recurrent infections of the respiratory and intestinal tract. Development of high-affinity antigen-specific antibodies involves two key actions of B-cell receptors (BCR): transmembrane signaling through BCR-complexes to induce B-cell differentiation and proliferation, and BCR-mediated antigen internalization for class-II MHC-mediated presentation to acquire antigen-specific CD4(+) T-cell help.We identified a variant (L3P) in the B-lymphoid tyrosine kinase (BLK) gene of 2 related CVID-patients, which was absent in healthy relatives. BLK belongs to the Src-kinases family and involved in BCR-signaling. Here, we sought to clarify BLK function in healthy human B-cells and its association to CVID.BLK expression was comparable in patient and healthy B-cells. Functional analysis of L3P-BLK showed reduced BCR crosslinking-induced Syk phosphorylation and proliferation, in both primary B-cells and B-LCLs. B-cells expressing L3P-BLK showed accelerated destruction of BCR-internalized antigen and reduced ability to elicit CD40L-expression on antigen-specific CD4(+) T-cells.In conclusion, we found a novel BLK gene variant in CVID-patients that causes suppressed B-cell proliferation and reduced ability of B-cells to elicit antigen-specific CD4(+) T-cell responses. Both these mechanisms may contribute to hypogammaglobulinemia in CVID-patients.
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21
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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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22
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Cartagena-Rivera AX, Wang WH, Geahlen RL, Raman A. Fast, multi-frequency, and quantitative nanomechanical mapping of live cells using the atomic force microscope. Sci Rep 2015; 5:11692. [PMID: 26118423 PMCID: PMC4484408 DOI: 10.1038/srep11692] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 06/03/2015] [Indexed: 11/08/2022] Open
Abstract
A longstanding goal in cellular mechanobiology has been to link dynamic biomolecular processes underpinning disease or morphogenesis to spatio-temporal changes in nanoscale mechanical properties such as viscoelasticity, surface tension, and adhesion. This requires the development of quantitative mechanical microscopy methods with high spatio-temporal resolution within a single cell. The Atomic Force Microscope (AFM) can map the heterogeneous mechanical properties of cells with high spatial resolution, however, the image acquisition time is 1-2 orders of magnitude longer than that required to study dynamic cellular processes. We present a technique that allows commercial AFM systems to map quantitatively the dynamically changing viscoelastic properties of live eukaryotic cells at widely separated frequencies over large areas (several 10's of microns) with spatial resolution equal to amplitude-modulation (AM-AFM) and with image acquisition times (tens of seconds) approaching those of speckle fluorescence methods. This represents a ~20 fold improvement in nanomechanical imaging throughput compared to AM-AFM and is fully compatible with emerging high speed AFM systems. This method is used to study the spatio-temporal mechanical response of MDA-MB-231 breast carcinoma cells to the inhibition of Syk protein tyrosine kinase giving insight into the signaling pathways by which Syk negatively regulates motility of highly invasive cancer cells.
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Affiliation(s)
- Alexander X. Cartagena-Rivera
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, USA
| | - Wen-Horng Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
| | - Robert L. Geahlen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, Indiana, USA
| | - Arvind Raman
- School of Mechanical Engineering, Purdue University, West Lafayette, Indiana, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana, USA
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23
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The ins and outs of MHC class II-mediated antigen processing and presentation. Nat Rev Immunol 2015; 15:203-16. [PMID: 25720354 DOI: 10.1038/nri3818] [Citation(s) in RCA: 601] [Impact Index Per Article: 66.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Antigenic peptide-loaded MHC class II molecules (peptide-MHC class II) are constitutively expressed on the surface of professional antigen-presenting cells (APCs), including dendritic cells, B cells, macrophages and thymic epithelial cells, and are presented to antigen-specific CD4(+) T cells. The mechanisms of antigen uptake, the nature of the antigen processing compartments and the lifetime of cell surface peptide-MHC class II complexes can vary depending on the type of APC. It is likely that these differences are important for the function of each distinct APC subset in the generation of effective adaptive immune responses. In this Review, we describe our current knowledge of the mechanisms of uptake and processing of antigens, the intracellular formation of peptide-MHC class II complexes, the intracellular trafficking of peptide-MHC class II complexes to the APC plasma membrane and their ultimate degradation.
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24
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Königsberger S, Weis V, Prodöhl J, Stehling M, Hobeika E, Reth M, Kiefer F. Suboptimal B-cell antigen receptor signaling activity in vivo elicits germinal center counterselection mechanisms. Eur J Immunol 2014; 45:603-11. [PMID: 25382621 DOI: 10.1002/eji.201444538] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 10/22/2014] [Accepted: 11/05/2014] [Indexed: 12/14/2022]
Abstract
Syk and Zap-70 constitute a closely related nonreceptor protein tyrosine kinase family, of which both members are functionally indispensable for conferring their respective antigen receptors with enzymatic activity. In this study, we analyze the impact of altering BCR signaling output on B-cell germinal center (GC) fate selection by constitutive, as well as inducible, monoallelic Syk kinase loss in the presence of a Zap-70 knock-in rescue allele. Cre-mediated Syk deletion in Syk(flox/Zap-70) B cells lowers pErk, but not pAkt-mediated signaling. Surprisingly, the use of a B-cell-specific constitutive mb1-cre deleter mouse model showed that a small cohort of peripheral Syk(flox/Zap-70);mb1-cre B cells efficiently circumvents deletion, which ultimately favors these Syk-sufficient cells to contribute to the GC reaction. Using a developmentally unbiased Syk(flox/Zap-70);mb1-creER(T2) approach in combination with an inducible tdRFP allele, we further demonstrate that this monoallelic deletion escape is not fully explained by leakiness of Cre expression, but is possibly the result of differential Syk locus accessibility in maturing B cells. Altogether, this underscores the importance of proper Syk kinase function not only during central and peripheral selection processes, but also during GC formation and maintenance.
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Affiliation(s)
- Sebastian Königsberger
- Max Planck Institute for Molecular Biomedicine, Mammalian Cell Signaling Laboratory, Münster, Germany
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25
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Abstract
Human germinal center-associated lymphoma (HGAL) is specifically expressed only in germinal center (GC) B lymphocytes and GC-derived lymphomas. HGAL protein decreases lymphocyte motility by inhibiting the ability of myosin to translocate actin via direct interaction with F-actin and myosin II and by activating RhoA signaling via direct interactions with RhoA-specific guanine nucleotide exchange factors. HGAL protein also regulates B-cell receptor (BCR) signaling by directly binding to and enhancing Syk kinase activity and activation of its downstream effectors. Herein we demonstrate that HGAL protein can be myristoylated and palmitoylated and that these modifications localize HGAL to cellular membrane raft microdomains with distinct consequences for BCR signaling and chemoattractant-induced cell mobility. In BCR signaling, raft localization of HGAL facilitates interaction with Syk and modulation of the BCR activation and signaling, which induces HGAL phosphorylation and redistribution from lipid raft to bulk membrane and cytoplasm, followed by degradation. In contrast, HGAL myristoylation and palmitoylation avert its inhibitory effects on chemoattractant-induced cell motility. These findings further elucidate the growing and complex role of HGAL in B-cell biology and suggest that membrane-bound and cytoplasmic HGAL protein differently regulates distinct biological processes.
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26
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A critical role for cell polarity in antigen extraction, processing, and presentation by B lymphocytes. Adv Immunol 2014; 123:51-67. [PMID: 24840947 DOI: 10.1016/b978-0-12-800266-7.00001-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
The activation of B lymphocytes in response to external stimuli represents a key step in the adaptive immune response, which is required for the production of high-affinity antibodies and for the generation of long-term memory. Because the dysregulation of B lymphocyte responses can lead to diverse pathological situations, B cells are considered today as valuable therapeutic targets for immunomodulation, in particular in the context of autoimmune reactions. Here, we review the fundamental molecular and cell biological mechanisms that enable B cells to efficiently sense, acquire, and respond to extracellular antigens. A special emphasis is given to cell polarity, which was shown to be critical for the regulation of antigen acquisition, processing, and presentation by B lymphocytes. How cell polarity coordinates the various steps of B lymphocyte activation and might impact the humoral immune response is further discussed.
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27
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Puri KD, Di Paolo JA, Gold MR. B-cell receptor signaling inhibitors for treatment of autoimmune inflammatory diseases and B-cell malignancies. Int Rev Immunol 2014; 32:397-427. [PMID: 23886342 DOI: 10.3109/08830185.2013.818140] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
B-cell receptor (BCR) signaling is essential for normal B-cell development, selection, survival, proliferation, and differentiation into antibody-secreting cells. Similarly, this pathway plays a key role in the pathogenesis of multiple B-cell malignancies. Genetic and pharmacological approaches have established an important role for the Spleen tyrosine kinase (Syk), Bruton's tyrosine kinase (Btk), and phosphatidylinositol 3-kinase isoform p110delta (PI3Kδ) in coupling the BCR and other BCRs to B-cell survival, migration, and activation. In the past few years, several small-molecule inhibitory drugs that target PI3Kδ, Btk, and Syk have been developed and shown to have efficacy in clinical trials for the treatment of several types of B-cell malignancies. Emerging preclinical data have also shown a critical role of BCR signaling in the activation and function of self-reactive B cells that contribute to autoimmune diseases. Because BCR signaling plays a major role in both B-cell-mediated autoimmune inflammation and B-cell malignancies, inhibition of this pathway may represent a promising new strategy for treating these diseases. This review summarizes recent achievements in the mechanism of action, pharmacological properties, and clinical activity and toxicity of these BCR signaling inhibitors, with a focus on their emerging role in treating lymphoid malignancies and autoimmune disorders.
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Courtney AH, Bennett NR, Zwick DB, Hudon J, Kiessling LL. Synthetic antigens reveal dynamics of BCR endocytosis during inhibitory signaling. ACS Chem Biol 2014; 9:202-10. [PMID: 24131142 DOI: 10.1021/cb400532y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
B cells detect foreign antigens through their B cell antigen receptor (BCR). The BCR, when engaged by antigen, initiates a signaling cascade. Concurrent with signaling is endocytosis of the BCR complex, which acts to downregulate signaling and facilitate uptake of antigen for processing and display on the cell surface. The relationship between signaling and BCR endocytosis is poorly defined. Here, we explore the interplay between BCR endocytosis and antigens that either promote or inhibit B cell activation. Specifically, synthetic antigens were generated that engage the BCR alone or both the BCR and the inhibitory co-receptor CD22. The lectin CD22, a member of the Siglec family, binds sialic acid-containing glycoconjugates found on host tissues, inhibiting BCR signaling to prevent erroneous B cell activation. At low concentrations, antigens that can cocluster the BCR and CD22 promote rapid BCR endocytosis; whereas, slower endocytosis occurs with antigens that bind only the BCR. At higher antigen concentrations, rapid BCR endocytosis occurs upon treatment with either stimulatory or inhibitory antigens. Endocytosis of the BCR, in response to synthetic antigens, results in its entry into early endocytic compartments. Although the CD22-binding antigens fail to activate key regulators of antigen presentation (e.g., Syk), they also promote BCR endocytosis, indicating that inhibitory antigens can be internalized. Together, our observations support a functional role for BCR endocytosis in downregulating BCR signaling. The reduction of cell surface BCR levels in the absence of B cell activation should raise the threshold for BCR subsequent activation. The ability of the activating synthetic antigens to trigger both signaling and entry of the BCR into early endosomes suggests strategies for targeted antigen delivery.
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Affiliation(s)
- Adam H. Courtney
- Department
of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Nitasha R. Bennett
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Daniel B. Zwick
- Department
of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
| | - Jonathan Hudon
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Laura L. Kiessling
- Department
of Biochemistry, University of Wisconsin—Madison, 433 Babcock Drive, Madison, Wisconsin 53706, United States
- Department
of Chemistry, University of Wisconsin—Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States
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29
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Yuseff MI, Pierobon P, Reversat A, Lennon-Duménil AM. How B cells capture, process and present antigens: a crucial role for cell polarity. Nat Rev Immunol 2013; 13:475-86. [PMID: 23797063 DOI: 10.1038/nri3469] [Citation(s) in RCA: 199] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
B cells are key components of the adaptive immune response. Their differentiation into either specific memory B cells or antibody-secreting plasma cells is a consequence of activation steps that involve the processing and presentation of antigens. The engagement of B cell receptors by surface-tethered antigens leads to the formation of an immunological synapse that coordinates cell signalling events and that promotes antigen uptake for presentation on MHC class II molecules. In this Review, we discuss membrane trafficking and the associated molecular mechanisms that are involved in antigen extraction and processing at the B cell synapse, and we highlight how B cells use cell polarity to coordinate the complex events that ultimately lead to efficient humoral responses.
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Saez de Guinoa J, Barrio L, Carrasco YR. Vinculin Arrests Motile B Cells by Stabilizing Integrin Clustering at the Immune Synapse. THE JOURNAL OF IMMUNOLOGY 2013; 191:2742-51. [DOI: 10.4049/jimmunol.1300684] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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31
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Yuseff MI, Lennon-Dumenil AM. Studying MHC class II presentation of immobilized antigen by B lymphocytes. Methods Mol Biol 2013; 960:529-543. [PMID: 23329512 DOI: 10.1007/978-1-62703-218-6_39] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
The ability of B lymphocytes to capture external antigens (Ag) and present them as peptide fragments, loaded on Major Histocompatibility complex (MHC) class II molecules, to CD4(+) T cells is a crucial part of the adaptive immune response. This allows T-B cooperation, a cellular communication that is required for B cells to develop into germinal centers (GC) and form mature high-affinity antibody producing cells and to further develop B cell memory. MHC class II antigen presentation by B lymphocytes is a multistep process involving (1) Recognition and capture of external Ag by B lymphocytes through their B cell receptor (BCR); (2) Ag processing, which comprises the degradation of Ag in internal compartments within the B cell and loading of the corresponding peptide fragments on MHC class II molecules and (3) Presentation of MHC II-peptide complexes to CD4(+) T cells. Here, we describe how to study MHC class II antigen presentation by B lymphocytes at these three major levels.
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Affiliation(s)
- M I Yuseff
- Institut Curie, Inserm U932, Paris, France
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32
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Affiliation(s)
- Oliver M Bannard
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, University of California-San Francisco, CA 94143-0414, USA
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33
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Gasparrini F, Molfetta R, Quatrini L, Frati L, Santoni A, Paolini R. Syk-dependent regulation of Hrs phosphorylation and ubiquitination upon FcεRI engagement: Impact on Hrs membrane/cytosol localization. Eur J Immunol 2012; 42:2744-53. [DOI: 10.1002/eji.201142278] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 05/09/2012] [Accepted: 06/06/2012] [Indexed: 01/24/2023]
Affiliation(s)
| | | | - Linda Quatrini
- Department of Molecular Medicine; “Sapienza” University of Rome; Rome; Italy
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34
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Katkere B, Rosa S, Drake JR. The Syk-binding ubiquitin ligase c-Cbl mediates signaling-dependent B cell receptor ubiquitination and B cell receptor-mediated antigen processing and presentation. J Biol Chem 2012; 287:16636-44. [PMID: 22451666 DOI: 10.1074/jbc.m112.357640] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
B cell receptor (BCR)-mediated antigen (Ag) processing and presentation lead to B cell-T cell interactions, which support affinity maturation and immunoglobulin class switching. These interactions are supported by generation of peptide-MHC class II complexes in multivesicular body-like MIIC compartments of B cells. Previous studies have shown that trafficking of Ag·BCR complexes to MVB-like MIIC occurs via an ubiquitin-dependent pathway and that ubiquitination of Ag·BCR complexes occurs by an Src family kinase signaling-dependent mechanism that is restricted to lipid raft-resident Ag·BCR complexes. This study establishes that downstream Syk-dependent BCR signaling is also required for BCR ubiquitination and BCR-mediated antigen processing and presentation. Knockdown studies reveal that of the two known Syk-binding E3 ubiquitin ligases c-Cbl and Cbl-b, only c-Cbl appears to have a central role in BCR ubiquitination, trafficking to MIIC, and ubiquitin-dependent BCR-mediated antigen processing and presentation. These results establish the novel role for Syk signaling and the Syk-binding ubiquitin ligase c-Cbl in the BCR-mediated processing and presentation of cognate antigen and define one mechanism by which antigen-induced BCR ubiquitination is modulated to impact the initiation and maturation of the humoral immune response.
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Affiliation(s)
- Bhuvana Katkere
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208, USA
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35
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Polarized Secretion of Lysosomes at the B Cell Synapse Couples Antigen Extraction to Processing and Presentation. Immunity 2011; 35:361-74. [DOI: 10.1016/j.immuni.2011.07.008] [Citation(s) in RCA: 133] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/30/2011] [Accepted: 07/08/2011] [Indexed: 11/17/2022]
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36
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Lahat N, Bitterman H, Weiss-Cerem L, Rahat MA. Hypoxia increases membranal and secreted HLA-DR in endothelial cells, rendering them T-cell activators. Transpl Int 2011; 24:1018-26. [PMID: 21806687 DOI: 10.1111/j.1432-2277.2011.01304.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transplantation involves preoperative ischemic periods that contribute to endothelial cell (EC) dysfunction and T-cell activation, leading to graft rejection. As hypoxia is a major constituent of ischemia, we evaluated its effect on the ability of ECs to express HLA-DR, which is required for presentation of antigens to T cells, and by itself serves as an important target for allogeneic T cells. Primary human umbilical vein ECs (HUVEC) and the human endothelial cell line EaHy926 were incubated in normoxia or hypoxia (PO(2) < 0.3%). Hypoxia increased the membranal expression (by 4-6 fold, P < 0.01) and secretion (by sixfold, P < 0.05) of HLA-DR protein, without influencing the accumulation of its mRNA. Alternative splicing, attenuated trafficking, or shedding from the plasma membrane were not observed, but the lysosomal inhibitor bafilomycin A1 reduced HLA-DR secretion. Hypoxia-induced endothelial HLA-DR elevated and diminished the secretion of IL-2 and IL-10, respectively, from co-cultured allogeneic CD4(+) T cells in a HLA-DR-dependent manner, as demonstrated by the use of monoclonal anti-HLA-DR. Our results indicate a yet not fully understood post-translational mechanism(s), which elevate both membranal and soluble HLA-DR expression. This elevation is involved in allogeneic T-cell activation, highlighting the pivotal role of ECs in ischemia/hypoxia-associated injury and graft rejection.
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Affiliation(s)
- Nitza Lahat
- Immunology Research Unit, Carmel Medical Center, The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
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37
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The mammalian actin-binding protein 1 (mAbp1): a novel molecular player in leukocyte biology. Trends Cell Biol 2011; 21:247-55. [DOI: 10.1016/j.tcb.2010.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/21/2010] [Accepted: 12/02/2010] [Indexed: 11/18/2022]
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38
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Harwood NE, Batista FD. The cytoskeleton coordinates the early events of B-cell activation. Cold Spring Harb Perspect Biol 2011; 3:a002360. [PMID: 21047917 PMCID: PMC3039531 DOI: 10.1101/cshperspect.a002360] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
B cells contribute to protective adaptive immune responses through generation of antibodies and long-lived memory cells, following engagement of the B-cell receptor (BCR) with specific antigen. Recent imaging investigations have offered novel insights into the ensuing molecular and cellular events underlying B-cell activation. Following engagement with antigen, BCR microclusters form and act as sites of active signaling through the recruitment of intracellular signaling molecules and adaptors. Signaling through these "microsignalosomes" is propagated and enhanced through B-cell spreading in a CD19-dependent manner. Subsequently, the mature immunological synapse is formed, and functions as a platform for antigen internalization, enabling the antigen presentation to helper T cells required for maximal B-cell activation. In this review, we discuss the emerging and critical role for the cytoskeleton in the coordination and regulation of these molecular events during B-cell activation.
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Affiliation(s)
- Naomi E Harwood
- Lymphocyte Interaction Laboratory, Cancer Research UK London Research Institute, Lincoln's Inn Fields Laboratories, London WC2A 3LY, United Kingdom
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39
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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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40
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Smith J, McDaid JP, Bhangal G, Chawanasuntorapoj R, Masuda ES, Cook HT, Pusey CD, Tam FWK. A spleen tyrosine kinase inhibitor reduces the severity of established glomerulonephritis. J Am Soc Nephrol 2009; 21:231-6. [PMID: 19959716 DOI: 10.1681/asn.2009030263] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Antibody-mediated glomerulonephritis, including that resulting from immune complexes, is an important cause of renal failure and is in need of more specific and effective treatment. Binding of antibody or immune complexes to Fc receptors activates intracellular signal transduction pathways, including spleen tyrosine kinase (Syk), leading to the production of inflammatory cytokines. We examined the effect of R788 (fostamatinib disodium), an oral prodrug of the selective Syk inhibitor R406, in nephrotoxic nephritis in Wistar-Kyoto rats. Treatment with R788 reduced proteinuria, tissue injury, glomerular macrophage and CD8+ cell numbers, and renal monocyte chemoattractant protein-1 (MCP-1) and IL-1beta, even when we started treatment after the onset of glomerulonephritis. When we administered R788 from days 4 to 10, glomerular crescents reduced by 100% (P < 0.01) compared with the vehicle group. When we administered R788 treatment from days 7 to 14, established glomerular crescents reversed (reduced by 21%, P < 0.001), and renal function was better than the vehicle group (P < 0.001). In vitro, R406 downregulated MCP-1 production from mesangial cells and macrophages stimulated with aggregated IgG. These results suggest that Syk is an important therapeutic target for the treatment of glomerulonephritis.
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Affiliation(s)
- Jennifer Smith
- Imperial College Kidney and Transplant Institute, Division of Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, United Kingdom
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41
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Abstract
Antigen receptors on the surface of B lymphocytes trigger adaptive immune responses after encountering their cognate antigens but also control a series of antigen-independent checkpoints during B cell development. These physiological processes are regulated by the expression and function of cell surface receptors, intracellular signaling molecules, and transcription factors. The function of these proteins can be altered by a dynamic array of post-translational modifications, using two interconnected mechanisms. These modifications can directly induce an altered conformational state in the protein target of the modification itself. In addition, they can create new binding sites for other protein partners, thereby contributing to where and when such multiple protein assemblies are activated within cells. As a new type of post-transcriptional regulator, microRNAs have emerged to influence the development and function of B cells by affecting the expression of target mRNAs.
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Yuseff MI, Lankar D, Lennon-Duménil AM. Dynamics of membrane trafficking downstream of B and T cell receptor engagement: impact on immune synapses. Traffic 2009; 10:629-36. [PMID: 19416472 PMCID: PMC2723867 DOI: 10.1111/j.1600-0854.2009.00913.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 03/12/2009] [Indexed: 12/01/2022]
Abstract
The onset of an adaptive immune response requires the activation of T and B lymphocytes by antigen-presenting cells, through a specialized form of intercellular communication, known as the immunological synapse (IS). In B lymphocytes the IS promotes efficient recognition and acquisition of membrane-bound Ags, while in T cells, it modulates the T cell response upon exposure to peptide-major histocompatibility complexes. In this review, we highlight the similarities that determine B and T cell activation, focusing on immune receptor downstream signaling events that lead to synapse formation. We stress the notion that polarization of T and B lymphocytes characterized by global changes in cytoskeleton and membrane trafficking modulates synapse structure and function, thus determining lymphocyte effector functions and fate.
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Affiliation(s)
| | - Danielle Lankar
- INSERM U932, Institut Curie12 rue Lhomond, 75005, Paris, France
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Sharma S, Orlowski G, Song W. Btk regulates B cell receptor-mediated antigen processing and presentation by controlling actin cytoskeleton dynamics in B cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 182:329-39. [PMID: 19109164 PMCID: PMC2855895 DOI: 10.4049/jimmunol.182.1.329] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The high efficiency of Ag processing and presentation by B cells requires Ag-induced BCR signaling and actin cytoskeleton reorganization, although the underlying mechanism for such requirements remains elusive. In this study, we identify Bruton's tyrosine kinase (Btk) as a linker connecting BCR signaling to actin dynamics and the Ag transport pathway. Using xid mice and a Btk inhibitor, we show that BCR engagement increases actin polymerization and Wiskott-Aldrich syndrome protein activation in a Btk-dependent manner. Concurrently, we observe Btk-dependent increases in the levels of phosphatidylinositide-4,5-bisphosphate and phosphorylated Vav upon BCR engagement. The rate of BCR internalization, its movement to late endosomes, and efficiency of BCR-mediated Ag processing and presentation are significantly reduced in both xid and Btk inhibitor-treated B cells. Thus, Btk regulates actin dynamics and Ag transport by activating Wiskott-Aldrich syndrome protein via Vav and phosphatidylinositides. This represents a novel mechanism by which BCR-mediated signaling regulates BCR-mediated Ag processing and presentation.
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Affiliation(s)
- Shruti Sharma
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Gregory Orlowski
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
| | - Wenxia Song
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742
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Fattakhova GV, Masilamani M, Narayanan S, Borrego F, Gilfillan AM, Metcalfe DD, Coligan JE. Endosomal trafficking of the ligated FcvarepsilonRI receptor. Mol Immunol 2008; 46:793-802. [PMID: 18945491 DOI: 10.1016/j.molimm.2008.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 08/29/2008] [Accepted: 09/03/2008] [Indexed: 12/21/2022]
Abstract
In addition to initiating signaling cascades leading to mast cell mediator release, aggregation of the high affinity IgE receptor (FcvarepsilonRI) leads to rapid internalization of the cross-linked receptor. However, little is known about the trafficking of the internalized FcvarepsilonRI. Here we demonstrate that in RBL-2H3 cells, aggregated FcvarepsilonRI appears in the early endosomal antigen 1 (EEA1(+)) domains of the early endosomes within 15min after ligation. Minimal co-localization of FcvarepsilonRI with Rab5 was observed by 30min, followed by its appearance in the Rab7(+) late endosomes and lysosomes at later time points. During endosomal sorting, FcvarepsilonRIalpha and gamma subunits remain associated. In Syk-deficient RBL-2H3 cells, the rate of transport to lysosomes is markedly increased. Taken together, our data demonstrate time-dependent sorting of aggregated FcvarepsilonRI within the endosomal-lysosomal network, and that Syk may play an essential role in regulating the trafficking and retention of FcvarepsilonRI in endosomes.
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Affiliation(s)
- Gul'nar V Fattakhova
- Receptor Cell Biology Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, United States
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45
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Onabajo OO, Seeley MK, Kale A, Qualmann B, Kessels M, Han J, Tan TH, Song W. Actin-binding protein 1 regulates B cell receptor-mediated antigen processing and presentation in response to B cell receptor activation. THE JOURNAL OF IMMUNOLOGY 2008; 180:6685-95. [PMID: 18453588 DOI: 10.4049/jimmunol.180.10.6685] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The BCR serves as both signal transducer and Ag transporter. Binding of Ags to the BCR induces signaling cascades and Ag processing and presentation, two essential cellular events for B cell activation. BCR-initiated signaling increases BCR-mediated Ag-processing efficiency by increasing the rate and specificity of Ag transport. Previous studies showed a critical role for the actin cytoskeleton in these two processes. In this study, we found that actin-binding protein 1 (Abp1/HIP-55/SH3P7) functioned as an actin-binding adaptor protein, coupling BCR signaling and Ag-processing pathways with the actin cytoskeleton. Gene knockout of Abp1 and overexpression of the Src homology 3 domain of Abp1 inhibited BCR-mediated Ag internalization, consequently reducing the rate of Ag transport to processing compartments and the efficiency of BCR-mediated Ag processing and presentation. BCR activation induced tyrosine phosphorylation of Abp1 and translocation of both Abp1 and dynamin 2 from the cytoplasm to plasma membrane, where they colocalized with the BCR and cortical F-actin. Mutations of the two tyrosine phosphorylation sites of Abp1 and depolymerization of the actin cytoskeleton interfered with BCR-induced Abp1 recruitment to the plasma membrane. The inhibitory effect of a dynamin proline-rich domain deletion mutant on the recruitment of Abp1 to the plasma membrane, coimmunoprecipitation of dynamin with Abp1, and coprecipitation of Abp1 with GST fusion of the dyanmin proline-rich domain demonstrate the interaction of Abp1 with dynamin 2. These results demonstrate that the BCR regulates the function of Abp1 by inducing Abp1 phosphorylation and actin cytoskeleton rearrangement, and that Abp1 facilitates BCR-mediated Ag processing by simultaneously interacting with dynamin and the actin cytoskeleton.
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Affiliation(s)
- Olusegun O Onabajo
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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46
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Jakus Z, Fodor S, Abram CL, Lowell CA, Mócsai A. Immunoreceptor-like signaling by beta 2 and beta 3 integrins. Trends Cell Biol 2007; 17:493-501. [PMID: 17913496 DOI: 10.1016/j.tcb.2007.09.001] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2007] [Revised: 08/08/2007] [Accepted: 09/11/2007] [Indexed: 11/23/2022]
Abstract
Although adhesion to extracellular structures is one of the most fundamental cell biological processes, the intracellular signals triggered by integrins, the most important receptors involved, are incompletely understood. Several recent reports indicate that signaling by beta(2) and beta(3) integrins in various cell types (neutrophils, macrophages, osteoclasts and platelets) use components of the signal transduction machinery of lymphocyte antigen receptors. Central to this immunoreceptor-like signaling is the phosphorylation of immunoreceptor tyrosine-based activation motif (ITAM)-containing adapters (such as DAP12 and the Fc receptor gamma-chain) by Src-family kinases and the concomitant recruitment of the Syk tyrosine kinase through its dual SH2 domains. These and other reports reveal an unexpected similarity between the signal-transduction mechanisms used by integrins and immune recognition receptors.
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Affiliation(s)
- Zoltán Jakus
- Department of Physiology, Semmelweis University School of Medicine, 1088 Budapest, Hungary
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