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Kirby D, Zilman A. Proofreading does not result in more reliable ligand discrimination in receptor signaling due to its inherent stochasticity. Proc Natl Acad Sci U S A 2023; 120:e2212795120. [PMID: 37192165 PMCID: PMC10214210 DOI: 10.1073/pnas.2212795120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 04/05/2023] [Indexed: 05/18/2023] Open
Abstract
Kinetic proofreading (KPR) has been used as a paradigmatic explanation for the high specificity of ligand discrimination by cellular receptors. KPR enhances the difference in the mean receptor occupancy between different ligands compared to a nonproofread receptor, thus potentially enabling better discrimination. On the other hand, proofreading also attenuates the signal and introduces additional stochastic receptor transitions relative to a nonproofreading receptor. This increases the relative magnitude of noise in the downstream signal, which can interfere with reliable ligand discrimination. To understand the effect of noise on ligand discrimination beyond the comparison of the mean signals, we formulate the task of ligand discrimination as a problem of statistical estimation of the receptor affinity of ligands based on the molecular signaling output. Our analysis reveals that proofreading typically worsens ligand resolution compared to a nonproofread receptor. Furthermore, the resolution decreases further with more proofreading steps under most commonly biologically considered conditions. This contrasts with the usual notion that KPR universally improves ligand discrimination with additional proofreading steps. Our results are consistent across a variety of different proofreading schemes and metrics of performance, suggesting that they are inherent to the KPR mechanism itself rather than any particular model of molecular noise. Based on our results, we suggest alternative roles for KPR schemes such as multiplexing and combinatorial encoding in multi-ligand/multi-output pathways.
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Affiliation(s)
- Duncan Kirby
- Department of Physics, University of Toronto, 60 St George St, Toronto, ONM5S 1A7, Canada
| | - Anton Zilman
- Department of Physics, University of Toronto, 60 St George St, Toronto, ONM5S 1A7, Canada
- Institute for Biomedical Engineering, University of Toronto, 164 college St, Toronto, ONM5S 1A7, Canada
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2
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Adnan A, Acharya S, Alenazy LA, de las Vecillas L, Giavina Bianchi P, Picard M, Calbache-Gil L, Romero-Pinedo S, Abadí´a-Molina AC, Kerr W, Pedicone C, Nagai J, Hollers E, Dwyer D, Castells M. Multistep IgE Mast Cell Desensitization Is a Dose- and Time-Dependent Process Partially Regulated by SHIP-1. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 210:709-720. [PMID: 36881903 PMCID: PMC9986054 DOI: 10.4049/jimmunol.2100485] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 12/22/2022] [Indexed: 03/09/2023]
Abstract
Multistep mast cell desensitization blocks the release of mediators following IgE crosslinking with increasing doses of Ag. Although its in vivo application has led to the safe reintroduction of drugs and foods in IgE-sensitized patients at risk for anaphylaxis, the mechanisms of the inhibitory process have remained elusive. We sought to investigate the kinetics, membrane, and cytoskeletal changes and to identify molecular targets. IgE-sensitized wild-type murine (WT) and FcεRIα humanized (h) bone marrow mast cells were activated and desensitized with DNP, nitrophenyl, dust mites, and peanut Ags. The movements of membrane receptors, FcεRI/IgE/Ag, actin, and tubulin and the phosphorylation of Syk, Lyn, P38-MAPK, and SHIP-1 were assessed. Silencing SHIP-1 protein was used to dissect the SHIP-1 role. Multistep IgE desensitization of WT and transgenic human bone marrow mast cells blocked the release of β-hexosaminidase in an Ag-specific fashion and prevented actin and tubulin movements. Desensitization was regulated by the initial Ag dose, number of doses, and time between doses. FcεRI, IgE, Ags, and surface receptors were not internalized during desensitization. Phosphorylation of Syk, Lyn, p38 MAPK, and SHIP-1 increased in a dose-response manner during activation; in contrast, only SHIP-1 phosphorylation increased in early desensitization. SHIP-1 phosphatase function had no impact on desensitization, but silencing SHIP-1 increased β-hexoxaminidase release, preventing desensitization. Multistep IgE mast cell desensitization is a dose- and time-regulated process that blocks β-hexosaminidase, impacting membrane and cytoskeletal movements. Signal transduction is uncoupled, favoring early phosphorylation of SHIP-1. Silencing SHIP-1 impairs desensitization without implicating its phosphatase function.
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Affiliation(s)
- Ather Adnan
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Texas A&M Health Science Center, College of Medicine, Houston, TX
| | - Shree Acharya
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Leila A. Alenazy
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Division of Allergy and Clinical Immunology, Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Leticia de las Vecillas
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
- Department of Allergy, Marqués de Valdecilla University Hospital – Instituto de Investigación Marques de Valdecilla, Santander, Spain
| | - Pedro Giavina Bianchi
- Clinical Immunology and Allergy Division, School of Medicine, Universidade de São Paulo, R. Prof. Artur Ramos Sao Paulo, Brazil
| | - Matthieu Picard
- Division of Allergy and Clinical Immunology, Department of Medicine, Hôpital Maisonneuve-Rosemont, Université de Montréal, Montreal, QC, Canada
| | - Lucia Calbache-Gil
- Unidad de Inmunología, IBIMER, CIBM, Universidad de Granada, Granada, Spain
- Departamento de Bioquímica y Biología Molecular III e Inmunología, Facultad de Medicina, Universidad de Granada, Granada, Spain
| | - Salvador Romero-Pinedo
- Unidad de Inmunología, IBIMER, CIBM, Universidad de Granada, Granada, Spain
- Departamento de Bioquímica y Biología Molecular III e Inmunología, Facultad de Medicina, Universidad de Granada, Granada, Spain
| | - Ana Clara Abadí´a-Molina
- Unidad de Inmunología, IBIMER, CIBM, Universidad de Granada, Granada, Spain
- Departamento de Bioquímica y Biología Molecular III e Inmunología, Facultad de Medicina, Universidad de Granada, Granada, Spain
| | - William Kerr
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY
| | - Chiara Pedicone
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, NY
| | - Jun Nagai
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Eleanor Hollers
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Daniel Dwyer
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
| | - Mariana Castells
- Division of Allergy and Immunology, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA
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3
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Schwartz SL, Cleyrat C, Olah MJ, Relich PK, Phillips GK, Hlavacek WS, Lidke KA, Wilson BS, Lidke DS. Differential mast cell outcomes are sensitive to FcεRI-Syk binding kinetics. Mol Biol Cell 2017; 28:3397-3414. [PMID: 28855374 PMCID: PMC5687039 DOI: 10.1091/mbc.e17-06-0350] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/21/2017] [Accepted: 08/22/2017] [Indexed: 11/11/2022] Open
Abstract
Cross-linking of immunoglobulin E-bound FcεRI triggers multiple cellular responses, including degranulation and cytokine production. Signaling is dependent on recruitment of Syk via docking of its dual SH2 domains to phosphorylated tyrosines within the FcεRI immunoreceptor tyrosine-based activation motifs. Using single-molecule imaging in live cells, we directly visualized and quantified the binding of individual mNeonGreen-tagged Syk molecules as they associated with the plasma membrane after FcεRI activation. We found that Syk colocalizes transiently to FcεRI and that Syk-FcεRI binding dynamics are independent of receptor aggregate size. Substitution of glutamic acid for tyrosine between the Syk SH2 domains (Syk-Y130E) led to an increased Syk-FcεRI off-rate, loss of site-specific Syk autophosphorylation, and impaired downstream signaling. Genome edited cells expressing only Syk-Y130E were deficient in antigen-stimulated calcium release, degranulation, and production of some cytokines (TNF-a, IL-3) but not others (MCP-1, IL-4). We propose that kinetic discrimination along the FcεRI signaling pathway occurs at the level of Syk-FcεRI interactions, with key outcomes dependent upon sufficiently long-lived Syk binding events.
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Affiliation(s)
- Samantha L Schwartz
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Cédric Cleyrat
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Mark J Olah
- Department of Physics, University of New Mexico, Albuquerque, NM 87131
| | - Peter K Relich
- Department of Physics, University of New Mexico, Albuquerque, NM 87131
| | - Genevieve K Phillips
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - William S Hlavacek
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545
| | - Keith A Lidke
- Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131.,Department of Physics, University of New Mexico, Albuquerque, NM 87131
| | - Bridget S Wilson
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131.,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
| | - Diane S Lidke
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131 .,Comprehensive Cancer Center, University of New Mexico, Albuquerque, NM 87131
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4
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Morishige T, Yoshioka Y, Narimatsu S, Ikemizu S, Tsunoda SI, Tsutsumi Y, Mukai Y, Okada N, Nakagawa S. Mutants of lymphotoxin-α with augmented cytotoxic activity via TNFR1 for use in cancer therapy. Cytokine 2012; 61:578-84. [PMID: 23246116 DOI: 10.1016/j.cyto.2012.11.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 09/29/2012] [Accepted: 11/06/2012] [Indexed: 11/15/2022]
Abstract
The cytokine lymphotoxin-α (LTα) is a promising candidate for use in cancer therapy. However, the instability of LTαin vivo and the insufficient levels of tumor necrosis factor receptor 1 (TNFR1)-mediated bioactivity of LTα limit its therapeutic potential. Here, we created LTα mutants with increased TNFR1-mediated bioactivity by using a phage display technique. We constructed a phage library displaying lysine-deficient structural variants of LTα with randomized amino acid residues. After affinity panning, we screened three clones of lysine-deficient LTα mutant, and identified a LTα mutant with TNFR1-mediated bioactivity that was 32 times that of the wild-type LTα (wtLTα). When compared with wtLTα, the selected clone showed augmented affinity to TNFR1 due to slow dissociation rather than rapid association. In contrast, the mutant showed only 4 times the TNFR2-mediated activity of wtLTα. In addition, the LTα mutant strongly and rapidly activated caspases that induce TNFR1-mediated cell death, whereas the mutant and wtLTα activated nuclear factor-kappa B to a similar extent. Our data suggest that the kinetics of LTα binding to TNFR1 play an important role in signal transduction patterns, and a TNFR1-selective LTα mutant with augmented bioactivity would be a superior candidate for cancer therapy.
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Affiliation(s)
- Tomohiro Morishige
- Laboratory of Biotechnology and Therapeutics, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan
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5
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Chung W, Abel SM, Chakraborty AK. Protein clusters on the T cell surface may suppress spurious early signaling events. PLoS One 2012; 7:e44444. [PMID: 22973450 PMCID: PMC3433417 DOI: 10.1371/journal.pone.0044444] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 08/06/2012] [Indexed: 12/16/2022] Open
Abstract
T cells play an important role in the adaptive immune system, quickly activating effector functions in response to small numbers of antigenic peptides but rarely activating in response to constant interaction with most endogenous peptides. Emerging experimental evidence suggests that key membrane-bound signaling proteins such as the T cell receptor and the adaptor protein Lat are spatially organized into small clusters on the T cell membrane. We use spatially resolved, stochastic computer simulations to study how the inhomogeneous distribution of molecules affects the portion of the T cell signaling network in which the kinase ZAP-70, originating in T cell receptor clusters, phosphorylates Lat. To gain insight into the effects of protein clustering, we compare the signaling response from membranes with clustered proteins to the signaling response from membranes with homogeneously distributed proteins. Given a fixed amount of ZAP-70 (a proxy for degree of TCR stimulation) that must diffuse into contact with Lat molecules, the spatially homogeneous system responds faster and results in higher levels of phosphorylated Lat. Analysis of the spatial distribution of proteins demonstrates that, in the homogeneous system, nearest ZAP-70 and Lat proteins are closer on average and fewer Lat molecules share the same closest ZAP-70 molecule, leading to the faster response time. The results presented here suggest that spatial clustering of proteins on the T cell membrane may suppress the propagation of signal from ZAP-70 to Lat, thus providing a regulatory mechanism by which T cells suppress transient, spurious signals induced by stimulation of T cell receptors by endogenous peptides. Because this suppression of spurious signals may occur at a cost to sensitivity, we discuss recent experimental results suggesting other potential mechanisms by which ZAP-70 and Lat may interact to initiate T cell activation.
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Affiliation(s)
- Woo Chung
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Steven M. Abel
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Arup K. Chakraborty
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Ragon Institute of MGH, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
- Harvard, Charlestown, Massachusetts, United States of America
- * E-mail:
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6
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Hořejší V, Otáhal P, Brdička T. LAT - an important raft-associated transmembrane adaptor protein. Delivered on 6 July 2009 at the 34th FEBS Congress in Prague, Czech Republic. FEBS J 2010; 277:4383-97. [DOI: 10.1111/j.1742-4658.2010.07831.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7
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Abstract
Mast cells are pivotal in innate immunity and play an important role in amplifying adaptive immunity. Nonetheless, they have long been known to be central to the initiation of allergic disorders. This results from the dysregulation of the immune response whereby normally innocuous substances are recognized as non-self, resulting in the production of IgE antibodies to these 'allergens'. Preformed and newly synthesized inflammatory (allergic) mediators are released from the mast cell following allergen-mediated aggregation of allergen-specific IgE bound to the high-affinity receptors for IgE (FcepsilonRI). Thus, the process by which the mast cell is able to interpret the engagement of FcepsilonRI into the molecular events necessary for release of their allergic mediators is of considerable therapeutic interest. Unraveling these molecular events has led to the discovery of a functional class of proteins that are essential in organizing activated signaling molecules and in coordinating and compartmentalizing their activity. These so-called 'adapters' bind multiple signaling proteins and localize them to specific cellular compartments, such as the plasma membrane. This organization is essential for normal mast cell responses. Here, we summarize the role of adapter proteins in mast cells focusing on the most recent advances toward understanding how these molecules work upon FcepsilonRI engagement.
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Affiliation(s)
- Damiana Alvarez-Errico
- Laboratory of Molecular Immunogenetics, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
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8
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Creation of lysine-deficient mutant lymphotoxin-α with receptor selectivity by using a phage display system. Biomaterials 2010; 31:1935-43. [DOI: 10.1016/j.biomaterials.2009.10.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2009] [Accepted: 10/07/2009] [Indexed: 12/20/2022]
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9
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Abstract
Multisite phosphorylation is an important mechanism for fine-tuned regulation of protein function. Mathematical models developed over recent years have contributed to elucidation of the functional consequences of a variety of molecular mechanisms involved in processing of the phosphorylation sites. Here we review the results of such models, together with salient experimental findings on multisite protein phosphorylation. We discuss how molecular mechanisms that can be distinguished with respect to the order and processivity of phosphorylation, as well as other factors, regulate changes in the sensitivity and kinetics of the response, the synchronization of molecular events, signalling specificity, and other functional implications.
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Affiliation(s)
- Carlos Salazar
- Research Group Modeling of Biological Systems (B086), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, Heidelberg, Germany.
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10
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Goldstein B, Coombs D, Faeder JR, Hlavacek WS. Kinetic proofreading model. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 640:82-94. [PMID: 19065786 DOI: 10.1007/978-0-387-09789-3_8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Kinetic proofreading is an intrinsic property of the cell signaling process. It arises as a consequence of the multiple interactions that occur after a ligand triggers a receptor to initiate a ignaling cascade and it ensures that false signals do not propagate to completion. In order for an active signaling complex to form after a ligand binds to a cell surface receptor, a sequence of binding and phosphorylation events must occur that are rapidly reversed if the ligand dissociates from the receptor. This gives rise to a mechanism by which cells can discriminate among ligands that bind to the same receptor but form ligand-receptor complexes with different lifetimes. We review experiments designed to test for kinetic proofreading and models that exhibit kinetic proofreading.
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Affiliation(s)
- Byron Goldstein
- Theoretical Biology and Biophysics Group, T-10 MS K710, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 875435, USA.
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Rivera J, Fierro NA, Olivera A, Suzuki R. New insights on mast cell activation via the high affinity receptor for IgE. Adv Immunol 2008; 98:85-120. [PMID: 18772004 PMCID: PMC2761150 DOI: 10.1016/s0065-2776(08)00403-3] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Mast cells are innate immune cells that function as regulatory or effector cells and serve to amplify adaptive immunity. In adaptive immunity these cells function primarily through cell surface Fc receptors that bind immunoglobulin antibodies. The dysregulation of their adaptive role makes them central players in allergy and asthma. Upon encountering an allergen (antigen), which is recognized by immunoglobulin E (IgE) antibodies bound to the high affinity IgE receptor (FcepsilonRI) expressed on their cell surface, mast cells secrete both preformed and newly synthesized mediators of the allergic response. Blocking of these responses is an objective in therapeutic intervention of allergic diseases. Thus, understanding the mechanisms by which antigens elicit mast cell activation (via FcepsilonRI) holds promise toward identifying therapeutic targets. Here we review the most recent advances in understanding antigen-dependent mast cell activation. Specifically, we focus on the requirements for FcepsilonRI activation, the regulation of calcium responses, co-stimulatory signals in FcepsilonRI-mediated mast cell activation and function, and how genetics influences mast cell signaling and responses. These recent discoveries open new avenues of investigation with therapeutic potential.
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Affiliation(s)
- Juan Rivera
- Laboratory of Immune Cell Signaling, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
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