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Fan S, Kang B, Li S, Li W, Chen C, Chen J, Deng L, Chen D, Zhou J. Exploring the multifaceted role of RASGRP1 in disease: immune, neural, metabolic, and oncogenic perspectives. Cell Cycle 2024; 23:722-746. [PMID: 38865342 PMCID: PMC11229727 DOI: 10.1080/15384101.2024.2366009] [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: 05/02/2023] [Accepted: 11/25/2023] [Indexed: 06/14/2024] Open
Abstract
RAS guanyl releasing protein 1 (RASGRP1) is a guanine nucleotide exchange factor (GEF) characterized by the presence of a RAS superfamily GEF domain. It functions as a diacylglycerol (DAG)-regulated nucleotide exchange factor, specifically activating RAS through the exchange of bound GDP for GTP. Activation of RAS by RASGRP1 has a wide range of downstream effects at the cellular level. Thus, it is not surprising that many diseases are associated with RASGRP1 disorders. Here, we present an overview of the structure and function of RASGRP1, its crucial role in the development, expression, and regulation of immune cells, and its involvement in various signaling pathways. This review comprehensively explores the relationship between RASGRP1 and various diseases, elucidates the underlying molecular mechanisms of RASGRP1 in each disease, and identifies potential therapeutic targets. This study provides novel insights into the role of RASGRP1 in insulin secretion and highlights its potential as a therapeutic target for diabetes. The limitations and challenges associated with studying RASGRP1 in disease are also discussed.
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Affiliation(s)
- Shangzhi Fan
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Bo Kang
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Shaoqian Li
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Weiyi Li
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- Department of Clinical Laboratory Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Canyu Chen
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Jixiang Chen
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Lijing Deng
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Danjun Chen
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
| | - Jiecan Zhou
- The First Affiliated Hospital, Hunan Provincial Clinical Medical Research Center for Drug Evaluation of Major Chronic Diseases,Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Clinical Pharmacology Research Center, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Hengyang Key Laboratory of Clinical Pharmacology, Hengyang Medical School, University of South China, Hengyang, Hunan, China
- The First Affiliated Hospital, Pharmacy Department, Hengyang Medical School, University of South China, Hengyang, Hunan, China
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2
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Zhang S, Zhu N, Gu J, Li HF, Qiu Y, Liao DF, Qin L. Crosstalk between Lipid Rafts and Aging: New Frontiers for Delaying Aging. Aging Dis 2022; 13:1042-1055. [PMID: 35855333 PMCID: PMC9286918 DOI: 10.14336/ad.2022.0116] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/16/2022] [Indexed: 12/15/2022] Open
Abstract
With the rapid aging in the global population, delay of aging has become a hot research topic. Lipid rafts (LRs) are microdomains in the plasma membrane that contain sphingolipids and cholesterol. Emerging evidence indicates an interesting interplay between LRs and aging. LRs and their components are altered with aging. Further, the aging process is strongly influenced by LRs. In recent years, LRs and their component signaling molecules have been recognized to affect aging by interfering with its hallmarks. Therefore, targeting LRs is a promising strategy to delay aging.
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Affiliation(s)
- Shuo Zhang
- 1Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, China
| | - Neng Zhu
- 2Department of Urology, The First Hospital of Hunan University of Chinese Medicine, Changsha, China
| | - Jia Gu
- 1Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, China
| | - Hong-Fang Li
- 1Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, China
| | - Yun Qiu
- 1Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, China
| | - Duan-Fang Liao
- 1Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, China
| | - Li Qin
- 1Division of Stem Cell Regulation and Application, School of Pharmacy, Hunan University of Chinese Medicine, Changsha, China.,3Hunan Province Engineering Research Center of Bioactive Substance Discovery of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Changsha, China
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3
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Arkee T, Hostager BS, Houtman JCD, Bishop GA. TRAF3 in T Cells Restrains Negative Regulators of LAT to Promote TCR/CD28 Signaling. THE JOURNAL OF IMMUNOLOGY 2021; 207:322-332. [PMID: 34145060 DOI: 10.4049/jimmunol.2001220] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 04/29/2021] [Indexed: 12/11/2022]
Abstract
The adaptor protein TNFR-associated factor 3 (TRAF3) is required for in vivo T cell effector functions and for normal TCR/CD28 signaling. TRAF3-mediated enhancement of TCR function requires engagement of both CD3 and CD28, but the molecular mechanisms underlying how TRAF3 interacts with and impacts TCR/CD28-mediated complexes to enhance their signaling remains an important knowledge gap. We investigated how TRAF3 is recruited to, and regulates, CD28 as a TCR costimulator. Direct association with known signaling motifs in CD28 was dispensable for TRAF3 recruitment; rather, TRAF3 associated with the CD28-interacting protein linker of activated T cells (LAT) in human and mouse T cells. TRAF3-LAT association required the TRAF3 TRAF-C domain and a newly identified TRAF2/3 binding motif in LAT. TRAF3 inhibited function of the LAT-associated negative regulatory protein Dok1, which is phosphorylated at an inhibitory tyrosine residue by the tyrosine kinase breast tumor kinase (Brk/PTK6). TRAF3 regulated Brk activation in T cells, limiting the association of protein tyrosine phosphatase 1B (PTP1B) with the LAT complex. In TRAF3-deficient cells, LAT complex-associated PTP1B was associated with dephosphorylation of Brk at an activating tyrosine residue, potentially reducing its ability to inhibit Dok1. Consistent with these findings, inhibiting PTP1B activity in TRAF3-deficient T cells rescued basal and TCR/CD28-mediated activation of Src family kinases. These results reveal a new mechanism for promotion of TCR/CD28-mediated signaling through restraint of negative regulation of LAT by TRAF3, enhancing the understanding of regulation of the TCR complex.
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Affiliation(s)
- Tina Arkee
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA.,Graduate Program in Immunology, The University of Iowa, Iowa City, IA.,Medical Scientist Training Program, The University of Iowa, Iowa City, IA
| | - Bruce S Hostager
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA
| | - Jon C D Houtman
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA.,Graduate Program in Immunology, The University of Iowa, Iowa City, IA.,Medical Scientist Training Program, The University of Iowa, Iowa City, IA
| | - Gail A Bishop
- Department of Microbiology and Immunology, The University of Iowa, Iowa City, IA; .,Graduate Program in Immunology, The University of Iowa, Iowa City, IA.,Medical Scientist Training Program, The University of Iowa, Iowa City, IA.,Department of Internal Medicine, The University of Iowa, Iowa City, IA; and.,Iowa City VA Medical Center, Iowa City, IA
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4
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Rakhmanova V, Park S, Lee S, Kim YH, Shin J. 3-Benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one suppresses FcεRI-mediated mast cell degranulation via the inhibition of mTORC2-Akt signaling. Biochem Biophys Res Commun 2020; 521:72-76. [PMID: 31629474 DOI: 10.1016/j.bbrc.2019.10.075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Accepted: 10/09/2019] [Indexed: 12/13/2022]
Abstract
Mast cells express high-affinity IgE receptor (FcεRI) on their surface, cross-linking of which leads to the immediate release of proinflammatory mediators such as histamine but also late-phase cytokine secretion, which are central to the pathogenesis of allergic diseases. Despite the growing evidences that mammalian target of rapamycin (mTOR) plays important roles in the immune system, it is still unclear how mTOR signaling regulates mast cell function. In this study, we investigated the effects of 3-benzyl-5-((2-nitrophenoxy) methyl)-dihydrofuran-2(3H)-one (3BDO) as an mTOR agonist on FcεRI-mediated allergic responses of mast cells. Our data showed that administration of 3BDO decreased β-hexosaminidase, interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) release in murine bone marrow-derived mast cells (BMMCs) after FcεRI cross-linking, which was associated with an increase in mTOR complex 1 (mTORC1) signaling but a decrease in activation of Erk1/2, Jnk, and mTORC2-Akt. In addition, we found that a specific Akt agonist, SC79, is able to fully restore the decrease of β-hexosaminidase release in 3BDO-treated BMMCs but has no effect on IL-6 release in these cells, suggesting that 3BDO negatively regulates FcεRI-mediated degranulation and cytokine release through differential mechanisms in mast cells. The present data demonstrate that proper activation of mTORC1 is crucial for mast cell effector function, suggesting the applicability of the mTORC1 activator as a useful therapeutic agent in mast cell-related diseases.
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Affiliation(s)
- Valeriya Rakhmanova
- Department of Microbiology, Inha University School of Medicine, Incheon, 22212, South Korea
| | - Sukyoung Park
- Department of Microbiology, Inha University School of Medicine, Incheon, 22212, South Korea
| | - Sungwook Lee
- Division of Tumor Immunology, National Cancer Center, Goyang, 10408, South Korea
| | - Young Hyo Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Inha University School of Medicine, Incheon, 22212, South Korea
| | - Jinwook Shin
- Department of Microbiology, Inha University School of Medicine, Incheon, 22212, South Korea.
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5
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Dashtsoodol N, Bortoluzzi S, Schmidt-Supprian M. T Cell Receptor Expression Timing and Signal Strength in the Functional Differentiation of Invariant Natural Killer T Cells. Front Immunol 2019; 10:841. [PMID: 31080448 PMCID: PMC6497757 DOI: 10.3389/fimmu.2019.00841] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/01/2019] [Indexed: 12/19/2022] Open
Abstract
The CD1d-restricted Vα14 invariant NKT (iNKT) cell lineage in mice (Vα24 in humans) represents an evolutionary conserved innate-like immune cell type that recognizes glycolipid antigens. Because of their unique ability to promptly secrete copious amounts of both pro-inflammatory and anti-inflammatory cytokines, typically produced by different T helper cell types, iNKT cells are implicated in the regulation of various pathologic conditions such as infection, allergy, autoimmune disease, maintenance of transplantation tolerance, and cancer. This striking multifaceted role in immune regulation is correlated with the presence of multiple functionally distinct iNKT cell subsets that can be distinguished based on the expression of characteristic surface markers and transcription factors. However, to date it, remains largely unresolved how this puzzling diversity of iNKT cell functional subsets emerges and what factors dictate the type of effector cell differentiation during the thymic differentiation considering the mono-specific nature of their T cell receptor (TCR) and their selecting molecule CD1d. Here, we summarize recent findings focusing on the role of TCR-mediated signaling and discuss possible mechanisms that may influence the sub-lineage choice of iNKT cells.
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Affiliation(s)
- Nyambayar Dashtsoodol
- Department of Hematology and Medical Oncology, Klinikum rechts der Isar and TranslaTUM Cancer Center, Technische Universität München, München, Germany.,Department of Microbiology and Immunology, School of Biomedicine, Mongolian National University of Medical Sciences, Ulaanbaatar, Mongolia
| | - Sabrina Bortoluzzi
- Department of Hematology and Medical Oncology, Klinikum rechts der Isar and TranslaTUM Cancer Center, Technische Universität München, München, Germany
| | - Marc Schmidt-Supprian
- Department of Hematology and Medical Oncology, Klinikum rechts der Isar and TranslaTUM Cancer Center, Technische Universität München, München, Germany
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6
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Wang LN, Gao MH, Wang B, Cong BB, Zhang SC. A role for GPI-CD59 in promoting T-cell signal transduction via LAT. Oncol Lett 2018. [PMID: 29541246 PMCID: PMC5835848 DOI: 10.3892/ol.2018.7908] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Cluster of differentiation 59 (CD59) is a glycosylphosphatidylinositol-anchored protein. Cross-linking of CD59 with specific monoclonal antibodies can cause a series of intracellular signal transduction events. However, the underlying molecular mechanisms are poorly understood. Linker for activation of T-cells (LAT) is a crucial adaptor protein in T-cell signaling, and its phosphorylation and palmitoylation are essential for its localization and function. In a previous study by the present authors, it was demonstrated that CD59 may be responsible for LAT palmitoylation, thereby regulating T-cell signal transduction. The present study detected the co-localization of LAT and CD59 in lipid rafts by transfecting Jurkat cells with lentivirus vectors carrying the LAT-enhanced green fluorescent protein fusion protein. In addition, LAT and CD59 were shown to have a synergistic effect on the proliferation of Jurkat cells. The results also indicated that CD59 may transfer the palmitate group from phosphatidylinositol to LAT to form LAT palmitate, which then localizes to lipid rafts to regulate T-cell activation. The results of the present study provided novel insights into the role of CD59 in T-cell signal transduction.
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Affiliation(s)
- Li-Na Wang
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China.,Department of Blood Transfusion, Qilu Hospital of Shandong University (Qingdao), Qingdao, Shandong 266071, P.R. China
| | - Mei-Hua Gao
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Bing Wang
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Bei-Bei Cong
- Department of Immunology, Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
| | - Shu-Chao Zhang
- Department of Transfusion, The Affiliated Hospital of Qingdao University Medical College, Qingdao, Shandong 266071, P.R. China
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7
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Lake D, Corrêa SAL, Müller J. Negative feedback regulation of the ERK1/2 MAPK pathway. Cell Mol Life Sci 2016; 73:4397-4413. [PMID: 27342992 PMCID: PMC5075022 DOI: 10.1007/s00018-016-2297-8] [Citation(s) in RCA: 351] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 01/04/2023]
Abstract
The extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signalling pathway regulates many cellular functions, including proliferation, differentiation, and transformation. To reliably convert external stimuli into specific cellular responses and to adapt to environmental circumstances, the pathway must be integrated into the overall signalling activity of the cell. Multiple mechanisms have evolved to perform this role. In this review, we will focus on negative feedback mechanisms and examine how they shape ERK1/2 MAPK signalling. We will first discuss the extensive number of negative feedback loops targeting the different components of the ERK1/2 MAPK cascade, specifically the direct posttranslational modification of pathway components by downstream protein kinases and the induction of de novo gene synthesis of specific pathway inhibitors. We will then evaluate how negative feedback modulates the spatiotemporal signalling dynamics of the ERK1/2 pathway regarding signalling amplitude and duration as well as subcellular localisation. Aberrant ERK1/2 activation results in deregulated proliferation and malignant transformation in model systems and is commonly observed in human tumours. Inhibition of the ERK1/2 pathway thus represents an attractive target for the treatment of malignant tumours with increased ERK1/2 activity. We will, therefore, discuss the effect of ERK1/2 MAPK feedback regulation on cancer treatment and how it contributes to reduced clinical efficacy of therapeutic agents and the development of drug resistance.
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Affiliation(s)
- David Lake
- Warwick Medical School, University of Warwick, Coventry, UK
| | - Sonia A L Corrêa
- School of Life Sciences, University of Warwick, Coventry, UK
- Faculty of Life Sciences, University of Bradford, Bradford, UK
| | - Jürgen Müller
- Warwick Medical School, University of Warwick, Coventry, UK.
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK.
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8
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Hrdinka M, Sudan K, Just S, Drobek A, Stepanek O, Schlüter D, Reinhold D, Jordan BA, Gintschel P, Schraven B, Kreutz MR. Normal Development and Function of T Cells in Proline Rich 7 (Prr7) Deficient Mice. PLoS One 2016; 11:e0162863. [PMID: 27657535 PMCID: PMC5033326 DOI: 10.1371/journal.pone.0162863] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 08/30/2016] [Indexed: 11/18/2022] Open
Abstract
Transmembrane adaptor proteins (TRAPs) are important organisers for the transduction of immunoreceptor-mediated signals. Prr7 is a TRAP that regulates T cell receptor (TCR) signalling and potently induces cell death when overexpressed in human Jurkat T cells. Whether endogenous Prr7 has a similar functional role is currently unknown. To address this issue, we analysed the development and function of the immune system in Prr7 knockout mice. We found that loss of Prr7 partially impairs development of single positive CD4+ T cells in the thymus but has no effect on the development of other T cell subpopulations, B cells, NK cells, or NKT cells. Moreover, Prr7 does not affect the TCR signalling pathway as T cells derived from Prr7 knockout and wild-type animals and stimulated in vitro express the same levels of the activation marker CD69, and retain their ability to proliferate and activate induced cell death programs. Importantly, Prr7 knockout mice retained the capacity to mount a protective immune response when challenged with Listeria monocytogenes infection in vivo. In addition, T cell effector functions (activation, migration, and reactivation) were normal following induction of experimental autoimmune encephalomyelitis (EAE) in Prr7 knockout mice. Collectively, our work shows that loss of Prr7 does not result in a major immune system phenotype and suggests that Prr7 has a dispensable function for TCR signalling.
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Affiliation(s)
- Matous Hrdinka
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg, Germany
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke University, Magdeburg, Germany
- * E-mail: (MH); (BS); (MRK)
| | - Kritika Sudan
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg, Germany
| | - Sissy Just
- Institute of Medical Microbiology, Otto-von-Guericke University, Germany
| | - Ales Drobek
- Group of Adaptive Immunity, Institute of Molecular Genetics, CAS, Prague, Czech Republic
| | - Ondrej Stepanek
- Group of Adaptive Immunity, Institute of Molecular Genetics, CAS, Prague, Czech Republic
| | - Dirk Schlüter
- Institute of Medical Microbiology, Otto-von-Guericke University, Germany
- Organ-Specific Immune Regulation, Helmholtz-Center of Infection Research (HZI). Braunschweig, Germany
| | - Dirk Reinhold
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke University, Magdeburg, Germany
| | - Bryen A. Jordan
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Patricia Gintschel
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke University, Magdeburg, Germany
| | - Burkhart Schraven
- Institute of Molecular and Clinical Immunology, Otto-von-Guericke University, Magdeburg, Germany
- Department of Immune Control, Helmholtz-Center of Infection Research (HZI). Braunschweig, Germany
- * E-mail: (MH); (BS); (MRK)
| | - Michael R. Kreutz
- RG Neuroplasticity, Leibniz-Institute for Neurobiology, Magdeburg, Germany
- Leibniz Group 'Dendritic Organelles and Synaptic Function', University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology, Hamburg, Germany
- * E-mail: (MH); (BS); (MRK)
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9
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Au-Yeung BB, Melichar HJ, Ross JO, Cheng DA, Zikherman J, Shokat KM, Robey EA, Weiss A. Quantitative and temporal requirements revealed for Zap70 catalytic activity during T cell development. Nat Immunol 2014; 15:687-94. [PMID: 24908390 PMCID: PMC4095875 DOI: 10.1038/ni.2918] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 05/06/2014] [Indexed: 02/06/2023]
Abstract
The catalytic activity of Zap70 is crucial for T cell antigen receptor (TCR) signaling, but the quantitative and temporal requirements for its function in thymocyte development are not known. Using a chemical-genetic system to selectively and reversibly inhibit Zap70 catalytic activity in a model of synchronized thymic selection, we showed that CD4(+)CD8(+) thymocytes integrate multiple, transient, Zap70-dependent signals over more than 36 h to reach a cumulative threshold for positive selection, whereas 1 h of signaling was sufficient for negative selection. Titration of Zap70 activity resulted in graded reductions in positive and negative selection but did not decrease the cumulative TCR signals integrated by positively selected OT-I cells, which revealed heterogeneity, even among CD4(+)CD8(+) thymocytes expressing identical TCRs undergoing positive selection.
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Affiliation(s)
- Byron B Au-Yeung
- 1] Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA. [2] Rosalind Russell-Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, San Francisco, California, USA. [3] Department of Medicine, University of California, San Francisco, San Francisco, California, USA. [4] Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA. [5]
| | - Heather J Melichar
- 1] Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California, USA. [2] [3]
| | - Jenny O Ross
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California, USA
| | - Debra A Cheng
- 1] Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA. [2] Rosalind Russell-Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, San Francisco, California, USA. [3] Department of Medicine, University of California, San Francisco, San Francisco, California, USA. [4] Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
| | - Julie Zikherman
- 1] Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA. [2] Rosalind Russell-Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, San Francisco, California, USA. [3] Department of Medicine, University of California, San Francisco, San Francisco, California, USA. [4] Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
| | - Kevan M Shokat
- 1] Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA. [2] Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, California, USA
| | - Ellen A Robey
- Division of Immunology and Pathogenesis, Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California, USA
| | - Arthur Weiss
- 1] Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, USA. [2] Rosalind Russell-Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, San Francisco, California, USA. [3] Department of Medicine, University of California, San Francisco, San Francisco, California, USA. [4] Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California, USA
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10
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Hrdinka M, Horejsi V. PAG - a multipurpose transmembrane adaptor protein. Oncogene 2013; 33:4881-92. [DOI: 10.1038/onc.2013.485] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/25/2013] [Accepted: 09/25/2013] [Indexed: 12/25/2022]
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11
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Dilek N, Poirier N, Usal C, Martinet B, Blancho G, Vanhove B. Control of transplant tolerance and intragraft regulatory T cell localization by myeloid-derived suppressor cells and CCL5. THE JOURNAL OF IMMUNOLOGY 2012; 188:4209-16. [PMID: 22450806 DOI: 10.4049/jimmunol.1101512] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature cells that are believed to inhibit immune responses in the contexts of cancer and organ transplantation, in association with regulatory T cells (Treg). However, the way in which MDSC cooperate with Treg remains elusive. In this study, we used DNA microarrays to analyze gene expression in blood-derived MDSC from rat recipients of kidney allografts. We found CCL5 (Rantes), a chemotactic C-C motif 5 chemokine, to be strongly downregulated after treatment with a tolerizing regimen. The amount of CCL5 protein was also lower in the plasma of tolerant recipients, whereas intragraft CCL5 was unchanged. Because CCL5 is chemotactic for Treg, we hypothesized that a gradient of CCL5 between the graft and peripheral blood might contribute to the intragraft localization of Treg in tolerant animals. To test this hypothesis, we treated tolerant rat recipients of kidney allografts with recombinant rat CCL5 to restore normal plasma concentrations. This led to a strong reduction in intragraft Treg monitored by immunohistofluorescence and by quantitative real-time PCR measurement of Foxp3 mRNA. Ultimately, this treatment led to an increase in serum creatinine concentrations and to kidney graft rejection after about a month. The kidney function of syngeneic grafts was not affected by a similar administration of CCL5. These data highlight the contribution of MDSC to the establishment of a graft-to-periphery CCL5 gradient in tolerant kidney allograft recipients, which controls recruitment of Treg to the graft where they likely contribute to maintaining tolerance.
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Affiliation(s)
- Nahzli Dilek
- INSERM, Unité Mixte de Recherche en Santé 1064, Nantes F-44093, France
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12
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Nag A, Monine M, Perelson AS, Goldstein B. Modeling and simulation of aggregation of membrane protein LAT with molecular variability in the number of binding sites for cytosolic Grb2-SOS1-Grb2. PLoS One 2012; 7:e28758. [PMID: 22396725 PMCID: PMC3291652 DOI: 10.1371/journal.pone.0028758] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 11/14/2011] [Indexed: 01/08/2023] Open
Abstract
The linker for activation of T cells (LAT), the linker for activation of B cells (LAB), and the linker for activation of X cells (LAX) form a family of transmembrane adaptor proteins widely expressed in lymphocytes. These scaffolding proteins have multiple binding motifs that, when phosphorylated, bind the SH2 domain of the cytosolic adaptor Grb2. Thus, the valence of LAT, LAB and LAX for Grb2 is variable, depending on the strength of receptor activation that initiates phosphorylation. During signaling, the LAT population will exhibit a time-varying distribution of Grb2 valences from zero to three. In the cytosol, Grb2 forms 1∶1 and 2∶1 complexes with the guanine nucleotide exchange factor SOS1. The 2∶1 complex can bridge two LAT molecules when each Grb2, through their SH2 domains, binds to a phosphorylated site on a separate LAT. In T cells and mast cells, after receptor engagement, receptor phosphoyrlation is rapidly followed by LAT phosphorylation and aggregation. In mast cells, aggregates containing more than one hundred LAT molecules have been detected. Previously we considered a homogeneous population of trivalent LAT molecules and showed that for a range of Grb2, SOS1 and LAT concentrations, an equilibrium theory for LAT aggregation predicts the formation of a gel-like phase comprising a very large aggregate (superaggregate). We now extend this theory to investigate the effects of a distribution of Grb2 valence in the LAT population on the formation of LAT aggregates and superaggregate and use stochastic simulations to calculate the fraction of the total LAT population in the superaggregate.
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Affiliation(s)
- Ambarish Nag
- Theoretical Biololgy and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, United States of America.
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13
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Chevrier S, Genton C, Malissen B, Malissen M, Acha-Orbea H. Dominant Role of CD80-CD86 Over CD40 and ICOSL in the Massive Polyclonal B Cell Activation Mediated by LAT(Y136F) CD4(+) T Cells. Front Immunol 2012; 3:27. [PMID: 22566911 PMCID: PMC3342035 DOI: 10.3389/fimmu.2012.00027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 02/09/2012] [Indexed: 12/26/2022] Open
Abstract
Coordinated interactions between T and B cells are crucial for inducing physiological B cell responses. Mutant mice in which tyrosine 136 of linker for activation of T cell (LAT) is replaced by a phenylalanine (LatY136F) exhibit a strong CD4+ T cell proliferation in the absence of intended immunization. The resulting effector T cells produce high amounts of TH2 cytokines and are extremely efficient at inducing polyclonal B cell activation. As a consequence, these LatY136F mutant mice showed massive germinal center formations and hypergammaglobulinemia. Here, we analyzed the involvement of different costimulators and their ligands in such T–B interactions both in vitro and in vivo, using blocking antibodies, knockout mice, and adoptive transfer experiments. Surprisingly, we showed in vitro that although B cell activation required contact with T cells, CD40, and inducible T cell costimulator molecule-ligand (ICOSL) signaling were not necessary for this process. These observations were further confirmed in vivo, where none of these molecules were required for the unfolding of the LAT CD4+ T cell expansion and the subsequent polyclonal B cell activation, although, the absence of CD40 led to a reduction of the follicular B cell response. These results indicate that the crucial functions played by CD40 and ICOSL in germinal center formation and isotype switching in physiological humoral responses are partly overcome in LatY136F mice. By comparison, the absence of CD80–CD86 was found to almost completely block the in vitro B cell activation mediated by LatY136F CD4+ T cells. The role of CD80–CD86 in T–B cooperation in vivo remained elusive due to the upstream implication of these costimulatory molecules in the expansion of LatY136F CD4+ T cells. Together, our data suggest that CD80 and CD86 costimulators play a key role in the polyclonal B cell activation mediated by LatY136F CD4+ T cells even though additional costimulatory molecules or cytokines are likely to be required in this process.
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Affiliation(s)
- Stéphane Chevrier
- Department of Biochemistry, University of Lausanne Lausanne, Switzerland
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14
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Zhu M, Fuller DM, Ou-Yang CW, Sullivan SA, Zhang W. Tyrosine phosphorylation-independent regulation of lipopolysaccharide-mediated response by the transmembrane adaptor protein LAB. THE JOURNAL OF IMMUNOLOGY 2012; 188:2733-41. [PMID: 22308309 DOI: 10.4049/jimmunol.1101581] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Linker for activation of B cells (LAB)/non-T cell activation linker is a transmembrane adaptor protein that functions in immunoreceptor-mediated signaling. Published studies have shown that LAB has both positive and negative roles in regulating TCR and high-affinity Fc receptor-mediated signaling and cellular function. In this study, we showed that LAB was also expressed in dendritic cells and that LAB deficiency affected LPS-mediated signaling and cytokine production. LPS-mediated MAPK activation was enhanced in LAB(-/-) bone marrow-derived dendritic cells. These bone marrow-derived dendritic cells also produced more TNF-α, IL-6, and IL-10 than wild-type cells. Moreover, LAB(-/-) mice were hyperresponsive to LPS-induced septic shock. These data indicated that LAB has a negative role in LPS-mediated responses. By using LAB knockin mice, which harbor mutations at five membrane-distal tyrosines, we further showed that, in contrast to its role in immunoreceptor-mediated signaling, LAB function in LPS-mediated signaling pathway did not depend on its tyrosine phosphorylation. Our study suggested a novel mechanism by which LAB functions in the regulation of innate immunity.
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Affiliation(s)
- Minghua Zhu
- Department of Immunology, Duke University Medical Center, Durham, NC 27710, USA
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15
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Draber P, Halova I, Levi-Schaffer F, Draberova L. Transmembrane adaptor proteins in the high-affinity IgE receptor signaling. Front Immunol 2012; 2:95. [PMID: 22566884 PMCID: PMC3342071 DOI: 10.3389/fimmu.2011.00095] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/28/2011] [Indexed: 11/24/2022] Open
Abstract
Aggregation of the high-affinity IgE receptor (FcεRI) initiates a cascade of signaling events leading to release of preformed inflammatory and allergy mediators and de novo synthesis and secretion of cytokines and other compounds. The first biochemically well defined step of this signaling cascade is tyrosine phosphorylation of the FcεRI subunits by Src family kinase Lyn, followed by recruitment and activation of spleen tyrosine kinase (Syk). Activity of Syk is decisive for the formation of multicomponent signaling assemblies, the signalosomes, in the vicinity of the receptors. Formation of the signalosomes is dependent on the presence of transmembrane adaptor proteins (TRAPs). These proteins are characterized by a short extracellular domain, a single transmembrane domain, and a cytoplasmic tail with various motifs serving as anchors for cytoplasmic signaling molecules. In mast cells five TRAPs have been identified [linker for activation of T cells (LAT), non-T cell activation linker (NTAL), linker for activation of X cells (LAX), phosphoprotein associated with glycosphingolipid-enriched membrane microdomains (PAG), and growth factor receptor-bound protein 2 (Grb2)-binding adaptor protein, transmembrane (GAPT)]; engagement of four of them (LAT, NTAL, LAX, and PAG) in FcεRI signaling has been documented. Here we discuss recent progress in the understanding of how TRAPs affect FcεRI-mediated mast cell signaling. The combined data indicate that individual TRAPs have irreplaceable roles in important signaling events such as calcium response, degranulation, cytokines production, and chemotaxis.
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Affiliation(s)
- Petr Draber
- Department of Signal Transduction, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic Prague, Czech Republic
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16
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Ferro M, Savino MT, Ortensi B, Finetti F, Genovese L, Masi G, Ulivieri C, Benati D, Pelicci G, Baldari CT. The Shc family protein adaptor, Rai, negatively regulates T cell antigen receptor signaling by inhibiting ZAP-70 recruitment and activation. PLoS One 2011; 6:e29899. [PMID: 22242145 PMCID: PMC3248456 DOI: 10.1371/journal.pone.0029899] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 12/08/2011] [Indexed: 12/16/2022] Open
Abstract
Rai/ShcC is a member of the Shc family of protein adaptors expressed with the highest abundance in the central nervous system, where it exerts a protective function by coupling neurotrophic receptors to the PI3K/Akt survival pathway. Rai is also expressed, albeit at lower levels, in other cell types, including T and B lymphocytes. We have previously reported that in these cells Rai attenuates antigen receptor signaling, thereby impairing not only cell proliferation but also, opposite to neurons, cell survival. Here we have addressed the mechanism underlying the inhibitory activity of Rai on TCR signaling. We show that Rai interferes with the TCR signaling cascade one of the earliest steps –recruitment of the initiating kinase ZAP-70 to the phosphorylated subunit of the TCR/CD3 complex, which results in a generalized dampening of the downstream signaling events. The inhibitory activity of Rai is associated to its inducible recruitment to phosphorylated CD3, which occurs in the physiological signaling context of the immune synapse. Rai is moreover found as a pre-assembled complex with ZAP-70 and also constitutively interacts with the regulatory p85 subunit of PI3K, similar to neuronal cells, notwithstanding the opposite biological outcome, i.e. impairment of PI-3K/Akt activation. The data highlight the ability of Rai to establish interactions with the TCR and key signaling mediators which, either directly (e.g. by inhibiting ZAP-70 recruitment to the TCR or sequestering ZAP-70/PI3K in the cytosol) or indirectly (e.g. by promoting the recruitment of effectors responsible for signal extinction) prevent full triggering of the TCR signaling cascade.
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Affiliation(s)
- Micol Ferro
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Maria Teresa Savino
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Barbara Ortensi
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Francesca Finetti
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Luca Genovese
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Giulia Masi
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Cristina Ulivieri
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Daniela Benati
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
| | - Giuliana Pelicci
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
| | - Cosima T. Baldari
- Department of Evolutionary Biology European Institute of Oncology, Milan, Italy
- Istituto Toscano Tumori, University of Siena, Siena, Italy
- * E-mail:
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17
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Abstract
Ras guanyl nucleotide releasing proteins (RasGRPs) are guanyl nucleotide exchange factors that activate Ras and related GTPases such as Rap. Like Sos proteins, RasGRPs have a catalytic region composed of a Ras exchange motif (REM) and a CDC25 domain. RasGRPs also possess a pair of atypical EF hands that may bind calcium in vivo and a C1 domain resembling the diacylglycerol (DAG)-binding domain of protein kinase C. DAG directly activates RasGRPs by a membrane recruitment mechanism as well as indirectly by PKC-mediated phosphorylation. RasGRPs are prominently expressed in blood cells. RasGRP1 acts downstream of TCR, while RasGRP1 and RasGRP3 both act downstream of BCR. Together, they regulate Ras in adaptive immune cells. RasGRP2, through Rap, plays a role in controlling platelet adhesion, while RasGRP4 controls Ras activation in mast cells. RasGRP malfunction likely contributes to autoimmunity and may contribute to blood malignancies. RasGRPs might prove to be viable drug targets. The intracellular site of RasGRP action and the relationship between RasGRPs and other Ras regulatory mechanisms are subjects of lively debate.
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Affiliation(s)
- James C Stone
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada
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SCIMP, a transmembrane adaptor protein involved in major histocompatibility complex class II signaling. Mol Cell Biol 2011; 31:4550-62. [PMID: 21930792 DOI: 10.1128/mcb.05817-11] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Formation of the immunological synapse between an antigen-presenting cell (APC) and a T cell leads to signal generation in both cells involved. In T cells, the lipid raft-associated transmembrane adaptor protein LAT plays a central role. Its phosphorylation is a crucial step in signal propagation, including the calcium response and mitogen-activated protein kinase activation, and largely depends on its association with the SLP76 adaptor protein. Here we report the discovery of a new palmitoylated transmembrane adaptor protein, termed SCIMP. SCIMP is expressed in B cells and other professional APCs and is localized in the immunological synapse due to its association with tetraspanin-enriched microdomains. In B cells, it is constitutively associated with Lyn kinase and becomes tyrosine phosphorylated after major histocompatibility complex type II (MHC-II) stimulation. When phosphorylated, SCIMP binds to the SLP65 adaptor protein and also to the inhibitory kinase Csk. While the association with SLP65 initiates the downstream signaling cascades, Csk binding functions as a negative regulatory loop. The results suggest that SCIMP is involved in signal transduction after MHC-II stimulation and therefore serves as a regulator of antigen presentation and other APC functions.
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19
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Chiang J, Hodes RJ. Cbl enforces Vav1 dependence and a restricted pathway of T cell development. PLoS One 2011; 6:e18542. [PMID: 21490975 PMCID: PMC3072394 DOI: 10.1371/journal.pone.0018542] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 03/03/2011] [Indexed: 11/29/2022] Open
Abstract
Extensive studies of pre-TCR- and TCR-dependent signaling have led to characterization of a pathway deemed essential for efficient T cell development, and comprised of a cascade of sequential events involving phosphorylation of Lck and ZAP-70, followed by phosphorylation of LAT and SLP-76, and subsequent additional downstream events. Of interest, however, reports from our lab as well as others have indicated that the requirements for ZAP-70, LAT, and SLP-76 are partially reversed by inactivation of c-Cbl (Cbl), an E3 ubiquitin ligase that targets multiple molecules for ubiquitination and degradation. Analysis of signaling events in these Cbl knockout models, including the recently reported analysis of SLP-76 transgenes defective in interaction with Vav1, suggested that activation of Vav1 might be a critical event in alternative pathways of T cell development. To extend the analysis of signaling requirements for thymic development, we have therefore assessed the effect of Cbl inactivation on the T cell developmental defects that occur in Vav1-deficient mice. The defects in Vav1-deficient thymic development, including a marked defect in DN3-DN4 transition, were completely reversed by Cbl inactivation, accompanied by enhanced phosphorylation of PLC-γ1 and ERKs in response to pre-TCR/TCR cross-linking of Vav1-/-Cbl-/- DP thymocytes. Taken together, these results suggest a substantially modified paradigm for pre-TCR/TCR signaling and T cell development. The observed consensus pathways of T cell development, including requirements for ZAP-70, LAT, SLP-76, and Vav1, appear to reflect the restriction by Cbl of an otherwise much broader set of molecular pathways capable of mediating T cell development.
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Affiliation(s)
- Jeffrey Chiang
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America.
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20
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Hrdinka M, Dráber P, Stepánek O, Ormsby T, Otáhal P, Angelisová P, Brdicka T, Paces J, Horejsí V, Drbal K. PRR7 is a transmembrane adaptor protein expressed in activated T cells involved in regulation of T cell receptor signaling and apoptosis. J Biol Chem 2011; 286:19617-29. [PMID: 21460222 DOI: 10.1074/jbc.m110.175117] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Transmembrane adaptor proteins (TRAPs) are important organizers and regulators of immunoreceptor-mediated signaling. A bioinformatic search revealed several potential novel TRAPs, including a highly conserved protein, proline rich 7 (PRR7), previously described as a component of the PSD-95/N-methyl-d-aspartate receptor protein complex in postsynaptic densities (PSD) of rat neurons. Our data demonstrate that PRR7 is weakly expressed in other tissues but is readily up-regulated in activated human peripheral blood lymphocytes. Transient overexpression of PRR7 in Jurkat T cell line led to gradual apoptotic death dependent on the WW domain binding motif surrounding Tyr-166 in the intracellular part of PRR7. To circumvent the pro-apoptotic effect of PRR7, we generated Jurkat clones with inducible expression of PRR7 (J-iPRR7). In these cells acute induction of PRR7 expression had a dual effect. It resulted in up-regulation of the transcription factor c-Jun and the activation marker CD69 as well as enhanced production of IL-2 after phorbol 12-myristate 13-acetate (PMA) and ionomycin treatment. On the other hand, expression of PRR7 inhibited general tyrosine phosphorylation and calcium influx after T cell receptor cross-linking by antibodies. Moreover, we found PRR7 constitutively tyrosine-phosphorylated and associated with Src. Collectively, these data indicate that PRR7 is a potential regulator of signaling and apoptosis in activated T cells.
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Affiliation(s)
- Matous Hrdinka
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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21
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Abstract
Docking proteins comprise a distinct category of intracellular, noncatalytic signalling protein, that function downstream of a variety of receptor and receptor-associated tyrosine kinases and regulate diverse physiological and pathological processes. The growth factor receptor bound 2-associated binder/Daughter of Sevenless, insulin receptor substrate, fibroblast growth factor receptor substrate 2 and downstream of tyrosine kinases protein families fall into this category. This minireview focuses on the structure, function and regulation of these proteins.
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Affiliation(s)
- Tilman Brummer
- Centre for Biological Systems Analysis (ZBSA), Albert-Ludwigs-University of Freiburg, Freiburg, Germany
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22
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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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23
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Capitani N, Lucherini OM, Baldari CT. Negative regulation of immunoreceptor signaling by protein adapters: Shc proteins join the club. FEBS Lett 2010; 584:4915-22. [DOI: 10.1016/j.febslet.2010.08.046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 08/23/2010] [Accepted: 08/31/2010] [Indexed: 11/26/2022]
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24
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Veillette A. Organization of immunoreceptor signaling by adapters. Immunol Rev 2009; 232:5-6. [PMID: 19909351 DOI: 10.1111/j.1600-065x.2009.00847.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- André Veillette
- Clinical Research Institute of Montreal, Montreal, QC, Canada.
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