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Liu M, Xia N, Zha L, Yang H, Gu M, Hao Z, Zhu X, Li N, He J, Tang T, Nie S, Zhang M, Lv B, Lu Y, Jiao J, Li J, Cheng X. Increased expression of protein tyrosine phosphatase nonreceptor type 22 alters early T-cell receptor signaling and differentiation of CD4 + T cells in chronic heart failure. FASEB J 2024; 38:e23386. [PMID: 38112398 DOI: 10.1096/fj.202300663r] [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: 04/06/2023] [Revised: 10/31/2023] [Accepted: 12/11/2023] [Indexed: 12/21/2023]
Abstract
CD4+ T-cell counts are increased and activated in patients with chronic heart failure (CHF), whereas regulatory T-cell (Treg) expansion is inhibited, probably due to aberrant T-cell receptor (TCR) signaling. TCR signaling is affected by protein tyrosine phosphatase nonreceptor type 22 (PTPN22) in autoimmune disorders, but whether PTPN22 influences TCR signaling in CHF remains unclear. This observational case-control study included 45 patients with CHF [18 patients with ischemic heart failure versus 27 patients with nonischemic heart failure (NIHF)] and 16 non-CHF controls. We used flow cytometry to detect PTPN22 expression, tyrosine phosphorylation levels, zeta-chain-associated protein kinase, 70 kDa (ZAP-70) inhibitory residue tyrosine 292 and 319 phosphorylation levels, and CD4+ T cell and Treg proportions. We conducted lentivirus-mediated PTPN22 RNA silencing in isolated CD4+ T cells. PTPN22 expression increased in the CD4+ T cells of patients with CHF compared with that in controls. PTPN22 expression was positively correlated with left ventricular end-diastolic diameter and type B natriuretic peptide but negatively correlated with left ventricular ejection fraction in the NIHF group. ZAP-70 tyrosine 292 phosphorylation was decreased, which correlated positively with PTPN22 overexpression in patients with NIHF and promoted early TCR signaling. PTPN22 silencing induced Treg differentiation in CD4+ T cells from patients with CHF, which might account for the reduced frequency of peripheral Tregs in these patients. PTPN22 is a potent immunomodulator in CHF and might play an essential role in the development of CHF by promoting early TCR signaling and impairing Treg differentiation from CD4+ T cells.
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Affiliation(s)
- Meilin Liu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ni Xia
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Lingfeng Zha
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haoyi Yang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Muyang Gu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zhiheng Hao
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xinyu Zhu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Nana Li
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Junyi He
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tingting Tang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shaofang Nie
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Min Zhang
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Bingjie Lv
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yuzhi Lu
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jiao Jiao
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jingyong Li
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiang Cheng
- Department of Cardiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Key Laboratory of Biological Targeted Therapy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Hubei Provincial Engineering Research Center of Immunological Diagnosis and Therapy for Cardiovascular Diseases, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Fernández-Aguilar LM, Vico-Barranco I, Arbulo-Echevarria MM, Aguado E. A Story of Kinases and Adaptors: The Role of Lck, ZAP-70 and LAT in Switch Panel Governing T-Cell Development and Activation. BIOLOGY 2023; 12:1163. [PMID: 37759563 PMCID: PMC10525366 DOI: 10.3390/biology12091163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 08/18/2023] [Accepted: 08/20/2023] [Indexed: 09/29/2023]
Abstract
Specific antigen recognition is one of the immune system's features that allows it to mount intense yet controlled responses to an infinity of potential threats. T cells play a relevant role in the host defense and the clearance of pathogens by means of the specific recognition of peptide antigens presented by antigen-presenting cells (APCs), and, to do so, they are equipped with a clonally distributed antigen receptor called the T-cell receptor (TCR). Upon the specific engagement of the TCR, multiple intracellular signals are triggered, which lead to the activation, proliferation and differentiation of T lymphocytes into effector cells. In addition, this signaling cascade also operates during T-cell development, allowing for the generation of cells that can be helpful in the defense against threats, as well as preventing the generation of autoreactive cells. Early TCR signals include phosphorylation events in which the tyrosine kinases Lck and ZAP70 are involved. The sequential activation of these kinases leads to the phosphorylation of the transmembrane adaptor LAT, which constitutes a signaling hub for the generation of a signalosome, finally resulting in T-cell activation. These early signals play a relevant role in triggering the development, activation, proliferation and apoptosis of T cells, and the negative regulation of these signals is key to avoid aberrant processes that could generate inappropriate cellular responses and disease. In this review, we will examine and discuss the roles of the tyrosine kinases Lck and ZAP70 and the membrane adaptor LAT in these cellular processes.
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Grants
- PY20_01297 Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, Spain
- PID2020-113943RB-I00 Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación, Spain
- PR2022-037 University of Cádiz
- PAIDI2020/DOC_01433 Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, Spain
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Affiliation(s)
- Luis M. Fernández-Aguilar
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Inmaculada Vico-Barranco
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Mikel M. Arbulo-Echevarria
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
| | - Enrique Aguado
- Institute for Biomedical Research of Cadiz (INIBICA), 11009 Cadiz, Spain; (L.M.F.-A.); (I.V.-B.); (M.M.A.-E.)
- Department of Biomedicine, Biotechnology and Public Health (Immunology), University of Cadiz, 11002 Cadiz, Spain
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3
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Damen H, Tebid C, Viens M, Roy DC, Dave VP. Negative Regulation of Zap70 by Lck Forms the Mechanistic Basis of Differential Expression in CD4 and CD8 T Cells. Front Immunol 2022; 13:935367. [PMID: 35860252 PMCID: PMC9289233 DOI: 10.3389/fimmu.2022.935367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/07/2022] [Indexed: 11/24/2022] Open
Abstract
Lck and Zap70, two non-receptor tyrosine kinases, play a crucial role in the regulation of membrane proximal TCR signaling critical for thymic selection, CD4/CD8 lineage choice and mature T cell function. Signal initiation upon TCR/CD3 and peptide/MHC interaction induces Lck-mediated phosphorylation of CD3 ITAMs. This is necessary for Zap70 recruitment and its phosphorylation by Lck leading to full Zap70 activation. In its native state Zap70 maintains a closed conformation creating an auto-inhibitory loop, which is relieved by Lck-mediated phosphorylation of Y315/Y319. Zap70 is differentially expressed in thymic subsets and mature T cells with CD8 T cells expressing the highest amount compared to CD4 T cells. However, the mechanistic basis of differential Zap70 expression in thymic subsets and mature T cells is not well understood. Here, we show that Zap70 is degraded relatively faster in DP and mature CD4 T cells compared to CD8 T cells, and inversely correlated with relative level of activated Zap70. Importantly, we found that Zap70 expression is negatively regulated by Lck activity: augmented Lck activity resulting in severe diminution in total Zap70. Moreover, Lck-mediated phosphorylation of Y315/Y319 was essential for Zap70 degradation. Together, these data shed light on the underlying mechanism of Lck-mediated differential modulation of Zap70 expression in thymic subsets and mature T cells.
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Affiliation(s)
- Hassan Damen
- Institute for Hematology-Oncology, Cell and Gene Therapy, Hopital Maisonneuve-Rosemont Research Center, Montreal, QC, Canada
| | - Christian Tebid
- Institute for Hematology-Oncology, Cell and Gene Therapy, Hopital Maisonneuve-Rosemont Research Center, Montreal, QC, Canada
| | - Melissa Viens
- Institute for Hematology-Oncology, Cell and Gene Therapy, Hopital Maisonneuve-Rosemont Research Center, Montreal, QC, Canada
| | - Denis-Claude Roy
- Institute for Hematology-Oncology, Cell and Gene Therapy, Hopital Maisonneuve-Rosemont Research Center, Montreal, QC, Canada
- Department of Medicine, University of Montreal, Montreal, QC, Canada
- *Correspondence: Denis-Claude Roy, ; Vibhuti P. Dave,
| | - Vibhuti P. Dave
- Institute for Hematology-Oncology, Cell and Gene Therapy, Hopital Maisonneuve-Rosemont Research Center, Montreal, QC, Canada
- *Correspondence: Denis-Claude Roy, ; Vibhuti P. Dave,
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Affiliation(s)
- Byron B. Au-Yeung
- Department of Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Neel H. Shah
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
| | - Lin Shen
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, California 94143, USA;,
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, University of California, San Francisco, California 94143, USA;,
- Howard Hughes Medical Institute, University of California, San Francisco, California 94143, USA
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5
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Intensity and duration of TCR signaling is limited by p38 phosphorylation of ZAP-70 T293 and destabilization of the signalosome. Proc Natl Acad Sci U S A 2018; 115:2174-2179. [PMID: 29440413 DOI: 10.1073/pnas.1713301115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ZAP-70 is a tyrosine kinase that is essential for initiation of T cell antigen receptor (TCR) signaling. We have found that T cell p38 MAP kinase (MAPK), which is directly phosphorylated and activated by ZAP-70 downstream of the TCR, in turn phosphorylates Thr-293 in the interdomain B region of ZAP-70. Mutant T cells expressing ZAP-70 with an alanine substitution at this residue (ZAP-70T293A) had enhanced TCR proximal signaling and increased effector responses. Lack of ZAP-70T293 phosphorylation increased association of ZAP-70 with the TCR and prolonged the existence of TCR signaling microclusters. These results identify a tight negative feedback loop in which ZAP-70-activated p38 reciprocally phosphorylates ZAP-70 and destabilizes the signaling complex.
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6
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Klammt C, Novotná L, Li DT, Wolf M, Blount A, Zhang K, Fitchett JR, Lillemeier BF. T cell receptor dwell times control the kinase activity of Zap70. Nat Immunol 2015; 16:961-9. [PMID: 26237552 DOI: 10.1038/ni.3231] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 06/22/2015] [Indexed: 12/15/2022]
Abstract
Kinase recruitment to membrane receptors is essential for signal transduction. However, the underlying regulatory mechanisms are poorly understood. We investigated how conformational changes control T cell receptor (TCR) association and activity of the kinase Zap70. Structural analysis showed that TCR binding or phosphorylation of Zap70 triggers a transition from a closed, autoinhibited conformation to an open conformation. Using Zap70 mutants with defined conformations, we found that TCR dwell times controlled Zap70 activity. The closed conformation minimized TCR dwell times and thereby prevented activation by membrane-associated kinases. Parallel recruitment of coreceptor-associated Lck kinase to the TCR ensured Zap70 phosphorylation and stabilized Zap70 TCR binding. Our study suggests that the dynamics of cytosolic enzyme recruitment to the plasma membrane regulate the activity and function of receptors lacking intrinsic catalytic activity.
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Affiliation(s)
- Christian Klammt
- Nomis Center for Immunobiology and Microbial Pathogenesis &Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Lucie Novotná
- Nomis Center for Immunobiology and Microbial Pathogenesis &Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Dongyang T Li
- Nomis Center for Immunobiology and Microbial Pathogenesis &Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Miriam Wolf
- Nomis Center for Immunobiology and Microbial Pathogenesis &Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Amy Blount
- Nomis Center for Immunobiology and Microbial Pathogenesis &Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, California, USA
| | - Kai Zhang
- Eli Lilly Inc., Lilly Biotechnology Center, San Diego, California, USA
| | | | - Björn F Lillemeier
- Nomis Center for Immunobiology and Microbial Pathogenesis &Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, California, USA
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Helou YA, Petrashen AP, Salomon AR. Vav1 Regulates T-Cell Activation through a Feedback Mechanism and Crosstalk between the T-Cell Receptor and CD28. J Proteome Res 2015; 14:2963-75. [PMID: 26043137 DOI: 10.1021/acs.jproteome.5b00340] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vav1, a Rac/Rho guanine nucleotide exchange factor and a critical component of the T-cell receptor (TCR) signaling cascade is tyrosine phosphorylated rapidly in response to T-cell activation. Vav1 has established roles in proliferation, cytokine secretion, Ca(2+) responses, and actin cytoskeleton regulation; however, its function in the regulation of phosphorylation of TCR components, including the ζ chain, the CD3 δ, ε, γ chains, and the associated kinases Lck and ZAP-70, is not well established. To obtain a more comprehensive picture of the role of Vav1 in receptor proximal signaling, we performed a wide-scale characterization of Vav1-dependent tyrosine phosphorylation events using quantitative phosphoproteomic analysis of Vav1-deficient T cells across a time course of TCR stimulation. Importantly, this study revealed a new function for Vav1 in the negative feedback regulation of the phosphorylation of immunoreceptor tyrosine-based activation motifs within the ζ chains, CD3 δ, ε, γ chains, as well as activation sites on the critical T cell tyrosine kinases Itk, Lck, and ZAP-70. Our study also uncovered a previously unappreciated role for Vav1 in crosstalk between the CD28 and TCR signaling pathways.
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Affiliation(s)
- Ynes A Helou
- †Department of Molecular Pharmacology, Physiology, and Biotechnology and ‡Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, United States
| | - Anna P Petrashen
- †Department of Molecular Pharmacology, Physiology, and Biotechnology and ‡Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, United States
| | - Arthur R Salomon
- †Department of Molecular Pharmacology, Physiology, and Biotechnology and ‡Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island 02903, United States
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8
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Increased PTPN22 expression and defective CREB activation impair regulatory T-cell differentiation in non-ST-segment elevation acute coronary syndromes. J Am Coll Cardiol 2015; 65:1175-1186. [PMID: 25814225 DOI: 10.1016/j.jacc.2015.01.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 01/07/2015] [Accepted: 01/14/2015] [Indexed: 01/08/2023]
Abstract
BACKGROUND Critical impairment of adaptive immune response has been observed in patients with acute coronary syndromes (ACS) with reduced expansion of regulatory T cells (Treg) and enhanced effector T-cell responsiveness, both associated with poorer outcomes. OBJECTIVES This study investigated the mechanisms underlying T-cell dysregulation in ACS. METHODS We evaluated both early and downstream T-cell receptor activation pathways after ex vivo stimulation with anti-CD3 and anti-CD28 crosslink in CD4(+) T cells from 20 patients with non-ST-segment elevation myocardial infarction (NSTEMI), 20 with stable angina (SA), and 20 controls. We reassessed 10 NSTEMI and 10 SA patients after 1 year. RESULTS Phospho-flow analysis revealed reduced phosphorylation of the zeta-chain-associated protein kinase of 70 kDa at the inhibitory residue tyrosine 292, enhancing T-cell activation, in NSTEMI helper T cells versus SA and controls (each, p < 0.001), resulting from increased expression of the protein tyrosine phosphatase, nonreceptor type, 22 (PTPN22) (p < 0.001 for both comparisons), persisting at follow-up. We also observed reduced phosphorylation (p < 0.001 versus controls) and lower levels of binding to interleukins 2 and 10 core promoter regions of the transcription factor cyclic adenosine monophosphate response element-binding protein (CREB) in NSTEMI (p < 0.05 vs. controls), which recovered at 1 year. Finally, in NSTEMI patients, helper T cells had a reduced ability in T-cell receptor-induced Treg generation (p = 0.002 vs. SA; p = 0.001 vs. controls), partially recovered at 1 year. Restoring CREB activity and silencing PTPN22 enhanced NSTEMI patients' ability to generate Treg. CONCLUSIONS The persistent overexpression of PTPN22 and the transient reduction of CREB activity, associated with impaired Treg differentiation, might play a role in ACS.
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Goodfellow HS, Frushicheva MP, Ji Q, Cheng DA, Kadlecek TA, Cantor AJ, Kuriyan J, Chakraborty AK, Salomon A, Weiss A. The catalytic activity of the kinase ZAP-70 mediates basal signaling and negative feedback of the T cell receptor pathway. Sci Signal 2015; 8:ra49. [PMID: 25990959 DOI: 10.1126/scisignal.2005596] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
T cell activation by antigens binding to the T cell receptor (TCR) must be properly regulated to ensure normal T cell development and effective immune responses to pathogens and transformed cells while avoiding autoimmunity. The Src family kinase Lck and the Syk family kinase ZAP-70 (ζ chain-associated protein kinase of 70 kD) are sequentially activated in response to TCR engagement and serve as critical components of the TCR signaling machinery that leads to T cell activation. We performed a mass spectrometry-based phosphoproteomic study comparing the quantitative differences in the temporal dynamics of phosphorylation in stimulated and unstimulated T cells with or without inhibition of ZAP-70 catalytic activity. The data indicated that the kinase activity of ZAP-70 stimulates negative feedback pathways that target Lck and thereby modulate the phosphorylation patterns of the immunoreceptor tyrosine-based activation motifs (ITAMs) of the CD3 and ζ chain components of the TCR and of signaling molecules downstream of Lck, including ZAP-70. We developed a computational model that provides a mechanistic explanation for the experimental findings on ITAM phosphorylation in wild-type cells, ZAP-70-deficient cells, and cells with inhibited ZAP-70 catalytic activity. This model incorporated negative feedback regulation of Lck activity by the kinase activity of ZAP-70 and predicted the order in which tyrosines in the ITAMs of TCR ζ chains must be phosphorylated to be consistent with the experimental data.
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Affiliation(s)
- Hanna Sjölin Goodfellow
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Maria P Frushicheva
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Qinqin Ji
- Department of Chemistry, Brown University, Providence, RI 02912, USA
| | - Debra A Cheng
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Theresa A Kadlecek
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
| | - Aaron J Cantor
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA
| | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.,California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720, USA.,Department of Chemistry, University of California, Berkeley, CA 94720, USA.,Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA.,Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Arup K Chakraborty
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Institute for Medical Engineering & Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.,Ragon Institute of MGH, MIT, and Harvard, Cambridge, MA 02139, USA
| | - Arthur Salomon
- Department of Chemistry, Brown University, Providence, RI 02912, USA.,Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Arthur Weiss
- Howard Hughes Medical Institute, UCSF, San Francisco, CA 94143, USA.,Department of Medicine, UCSF, San Francisco, CA 94143, USA
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10
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Friend SF, Deason-Towne F, Peterson LK, Berger AJ, Dragone LL. Regulation of T cell receptor complex-mediated signaling by ubiquitin and ubiquitin-like modifications. AMERICAN JOURNAL OF CLINICAL AND EXPERIMENTAL IMMUNOLOGY 2014; 3:107-123. [PMID: 25628960 PMCID: PMC4299764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Accepted: 11/10/2014] [Indexed: 06/04/2023]
Abstract
Post-translational protein modifications are a dynamic method of regulating protein function in response to environmental signals. As with any cellular process, T cell receptor (TCR) complex-mediated signaling is highly regulated, since the strength and duration of TCR-generated signals governs T cell development and activation. While regulation of TCR complex-mediated signaling by phosphorylation has been well studied, regulation by ubiquitin and ubiquitin-like modifiers is still an emerging area of investigation. This review will examine how ubiquitin, E3 ubiquitin ligases, and other ubiquitin-like modifications such as SUMO and NEDD8 regulate TCR complex-mediated signaling.
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Affiliation(s)
- Samantha F Friend
- Department of Pediatrics, University of Colorado School of MedicineAurora, CO 80045, USA
- Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish HealthDenver, CO 80206, USA
| | - Francina Deason-Towne
- Department of Pediatrics, University of Colorado School of MedicineAurora, CO 80045, USA
- Department of Biology, Regis UniversityDenver, CO 80221, USA
| | - Lisa K Peterson
- Department of Pediatrics, University of Colorado School of MedicineAurora, CO 80045, USA
- Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish HealthDenver, CO 80206, USA
| | - Allison J Berger
- Takeda Pharmaceuticals International Co.Cambridge, MA 02139, USA
| | - Leonard L Dragone
- Department of Pediatrics, University of Colorado School of MedicineAurora, CO 80045, USA
- Integrated Department of Immunology, University of Colorado School of Medicine and National Jewish HealthDenver, CO 80206, USA
- Division of Rheumatology, Colorado Children’s HospitalAurora, CO 80045, USA
- Since completing this study, Dr. Dragone has joined Genentech, a member of the Roche group. GenentechSouth San Francisco, CA 94090, USA
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11
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Insight into the therapeutic aspects of ‘Zeta-Chain Associated Protein Kinase 70kDa’ inhibitors: A review. Cell Signal 2014; 26:2481-92. [DOI: 10.1016/j.cellsig.2014.06.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 06/27/2014] [Indexed: 01/06/2023]
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12
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Structural basis for activation of ZAP-70 by phosphorylation of the SH2-kinase linker. Mol Cell Biol 2013; 33:2188-201. [PMID: 23530057 DOI: 10.1128/mcb.01637-12] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Serial activation of the tyrosine kinases Lck and ZAP-70 initiates signaling downstream of the T cell receptor. We previously reported the structure of an autoinhibited ZAP-70 variant in which two regulatory tyrosine residues (315 and 319) in the SH2-kinase linker were replaced by phenylalanine. We now present a crystal structure of ZAP-70 in which Tyr 315 and Tyr 319 are not mutated, leading to the recognition of a five-residue sequence register error in the SH2-kinase linker of the original crystallographic model. The revised model identifies distinct roles for these two tyrosines. As seen in a recently reported structure of the related tyrosine kinase Syk, Tyr 315 of ZAP-70 is part of a hydrophobic interface between the regulatory apparatus and the kinase domain, and the integrity of this interface would be lost upon engagement of doubly phosphorylated peptides by the SH2 domains. Tyr 319 is not necessarily dislodged by SH2 engagement, which activates ZAP-70 only ∼5-fold in vitro. In contrast, phosphorylation by Lck activates ZAP-70 ∼100-fold. This difference is due to the ability of Tyr 319 to suppress ZAP-70 activity even when the SH2 domains are dislodged from the kinase domain, providing stringent control of ZAP-70 activity downstream of Lck.
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13
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Szabo M, Czompoly T, Kvell K, Talaber G, Bartis D, Nemeth P, Berki T, Boldizsar F. Fine-tuning of proximal TCR signaling by ZAP-70 tyrosine residues in Jurkat cells. Int Immunol 2011; 24:79-87. [PMID: 22207134 DOI: 10.1093/intimm/dxr105] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Zeta-chain-associated protein kinase of 70kDa (ZAP-70) kinase is a key regulator in the early steps of TCR signaling but some aspects of its fine regulation are still unclear. From its 31 tyrosine (Y) residues, 11 phosphorylation sites have been identified, some with activator (Y315 and Y493) or inhibitory (Y292 and Y492) and others with unknown function (Y069, Y126 and Y178). In our present work, we aimed to elucidate the role of different Y residues of ZAP-70, especially those with unknown function, in calcium signaling and the autoregulation of the kinase. ZAP-70-deficient Jurkat cells (P116) were stably reconstituted with point-mutated ZAP-70 constructs where tyrosine residues 069, 126, 178, 238, 292, 315, 492 or 493 were replaced with phenylalanine (F). The anti-CD3-elicited calcium signal increased in F069-, F292- and F492-ZAP-70-expressing cell lines but decreased in the F126-, F315- and F493-ZAP-70-expressing cell lines. ZAP-70 point mutations led to phosphorylation changes predominantly in SH2 domain containing leukocyte protein of 76kDa (SLP-76) but not linker of activated T cells (LAT) during CD3-activation; moreover, we detected basal hyperphosphorylation of SLP-76 Y128 in the F126-, F178- and F492-ZAP-70-expressing cell lines. In summary, Y069, Y178, Y292 and Y492 have inhibitory, while Y126, Y315 and Y493 activator role in anti-CD3-induced T-cell activation. Phosphorylation changes in LAT and SLP-76 suggest that fine regulation of ZAP-70 on calcium signaling is rather transmitted through SLP-76 not LAT. Additionally, negative or positive autoregulatory function of Y292 and Y493 or Y315, respectively, was revealed in ZAP-70. These data indicate that previously not characterized Y069, Y126 and Y178 in ZAP-70 participate in the fine regulation of TCR signaling.
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Affiliation(s)
- M Szabo
- Department of Immunology and Biotechnology, University of Pecs, H-7643 Pecs, Hungary
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14
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Iwai LK, Benoist C, Mathis D, White FM. Quantitative phosphoproteomic analysis of T cell receptor signaling in diabetes prone and resistant mice. J Proteome Res 2010; 9:3135-45. [PMID: 20438120 DOI: 10.1021/pr100035b] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Type 1 diabetes, in human patients and NOD mice, results from an immune attack on insulin-producing beta-cells of the pancreas by autoreactive T lymphocytes. In NOD mice, genetically controlled perturbations in the signaling pathways downstream of the antigen-specific T cell receptor (TCR) may be instrumental in the altered responses of T cells, manifest as inefficient induction of apoptosis after recognition of self-antigens in the thymus or as perturbed reactivity of mature T cells in peripheral organs. To map this signaling difference(s), we have used mass spectrometry-based quantitative phosphoproteomics to compare the activation of primary CD4(+) T cells of diabetes-prone NOD and -resistant B6.H2g7 mice. Immunoprecipitation and IMAC purification of tyrosine-phosphorylated peptides, combined with a stable-isotope iTRAQ labeling, enabled us to identify and quantify over 77 phosphorylation events in 54 different proteins downstream of TCR stimulation of primary CD4(+) T cells. This analysis showed a generally higher level of phosphotyrosine in activated NOD cells, as well as several phosphorylation sites that appeared to be differentially regulated in these two strains (involving TXK, CD5, PAG1, and ZAP-70). These data highlight the differences in signaling between CD4(+) T cell compartments of NOD and B6g7 mice and may underlie the dysregulation of T cells in NOD mice.
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Affiliation(s)
- Leo K Iwai
- Department of Pathology, Harvard Medical School and Section on Immunology and Immunogenetics, Joslin Diabetes Center, Boston, Massachusetts, USA
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15
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Wang H, Kadlecek TA, Au-Yeung BB, Goodfellow HES, Hsu LY, Freedman TS, Weiss A. ZAP-70: an essential kinase in T-cell signaling. Cold Spring Harb Perspect Biol 2010; 2:a002279. [PMID: 20452964 DOI: 10.1101/cshperspect.a002279] [Citation(s) in RCA: 268] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
ZAP-70 is a cytoplasmic protein tyrosine kinase that plays a critical role in the events involved in initiating T-cell responses by the antigen receptor. Here we review the structure of ZAP-70, its regulation, its role in development and in disease. We also describe a model experimental system in which ZAP-70 function can be interrupted by a small chemical inhibitor.
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Affiliation(s)
- Haopeng Wang
- Howard Hughes Medical Institute, Rosalind Russell Medical Research Center for Arthritis, Department of Medicine, University of California, San Francisco, San Francisco, California 94143, USA
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16
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Abstract
Development, survival, and activation of B lymphocytes are controlled by signals emanating from the B-cell antigen receptor (BCR). The BCR has an autonomous signaling function also known as tonic signaling that allows for long-term survival of B cells in the immune system. Upon binding of antigen to the BCR, the tonic signal is amplified and diversified, leading to alteration in gene expression and B-cell activation. The spleen tyrosine kinase (Syk) intimately cooperates with the signaling subunits of the BCR and plays a central role in the amplification and diversification of BCR signals. In this review, we discuss the molecular mechanisms by which Syk activity is inhibited and activated at the BCR. Importantly, Syk acts not only as a kinase that phosphorylates downstream substrates but also as an adapter that can bind to a diverse set of signaling proteins. Depending on its interactions and localization, Syk can signal opposing cell fate decisions such as proliferation or differentiation of B cells.
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Affiliation(s)
- Yogesh Kulathu
- Centre for Biological Signaling Studies (Bioss) and Department of Molecular Immunology, Faculty of Biology, Albert-Ludwigs-Universität Freiburg and Max-Planck Institute for Immunobiology, Freiburg, Germany
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17
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Dragone LL, Shaw LA, Myers MD, Weiss A. SLAP, a regulator of immunoreceptor ubiquitination, signaling, and trafficking. Immunol Rev 2010; 232:218-28. [PMID: 19909366 DOI: 10.1111/j.1600-065x.2009.00827.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Src-like adapter proteins (SLAP and SLAP-2) constitute a family of proteins that are expressed in a variety of cell types but are studied most extensively in lymphocytes. They have been shown to associate with proximal components of the T-cell receptor (TCR) and B-cell receptor (BCR) signaling complexes. An interaction of SLAP with c-Cbl leads to the ubiquitination and degradation of phosphorylated components of the TCR- and BCR-signaling complexes. The absence of this process in immature SLAP-deficient T and B cells leads to increased immunoreceptor levels due to decreased intracellular retention and degradation. We propose a model in which SLAP-dependent regulation of immunoreceptor levels allows for finer control of immunoreceptor signaling. Thus, SLAP functions to dampen immunoreceptor signaling, thereby influencing lymphocyte development and repertoire selection.
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18
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Fischer A, Picard C, Chemin K, Dogniaux S, le Deist F, Hivroz C. ZAP70: a master regulator of adaptive immunity. Semin Immunopathol 2010; 32:107-16. [DOI: 10.1007/s00281-010-0196-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Accepted: 12/29/2009] [Indexed: 10/24/2022]
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19
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Stability of an autoinhibitory interface in the structure of the tyrosine kinase ZAP-70 impacts T cell receptor response. Proc Natl Acad Sci U S A 2009; 106:20699-704. [PMID: 19920178 DOI: 10.1073/pnas.0911512106] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The delivery of signals from the activated T cell antigen receptor (TCR) inside the cell relies on the protein tyrosine kinase ZAP-70 (zeta-associated protein of 70 kDa). A recent crystal structure of inactive full-length ZAP-70 suggests that a central interface formed by the docking of the two SH2 domains of ZAP-70 onto the kinase domain is crucial for suppressing catalytic activity. Here we validate the significance of this autoinhibitory interface for the regulation of ZAP-70 catalytic activity and the T cell response. For this purpose, we perform in vitro catalytic activity assays and binding experiments using ZAP-70 proteins purified from insect cells to examine activation of ZAP-70. Furthermore, we use cell lines stably expressing wild-type or mutant ZAP-70 to monitor proximal events in T cell signaling, including TCR-induced phosphorylation of ZAP-70 substrates, activation of the MAP kinase pathway, and intracellular Ca(2+) levels. Taken together, our results directly correlate the stability of the autoinhibitory interface with the activation of these key events in the T cell response.
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20
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Abstract
The series of events leading to T-cell activation following antigen recognition has been extensively investigated. Although the exact mechanisms of ligand binding and transmission of this extracellular interaction into a productive intracellular signaling sequence remains incomplete, it has been known for many years that the immunoreceptor tyrosine activation motifs (ITAMs) of the T-cell receptor (TCR):CD3 complex are required for initiation of this signaling cascade because of the recruitment and activation of multiple protein tyrosine kinases, signaling intermediates, and adapter molecules. It however remains unclear why the TCR:CD3 complex requires 10 ITAMs, while many other ITAM-containing immune receptors, such as Fc receptors (FcRs) and the B cell receptor (BCR), contain far fewer ITAMs. We have recently demonstrated that various parameters of T cell development and activation are influenced by the number, as well as location and type, of ITAMs within the TCR:CD3 complex and hence propose that the TCR is capable of 'scalable signaling' that facilitates the initiation and orchestration of diverse T-cell functions. While many of the underlying mechanisms remain hypothetical, this review intends to amalgamate what we have learned from conventional biochemical analyses regarding initiation and diversification of T-cell signaling, with more recent evidence from molecular and fluorescent microscopic analyses, to propose a broader purpose for the TCR:CD3 ITAMs. Rather than simply signal initiation, individual ITAMs may also be responsible for the differential recruitment of signaling and regulatory molecules which ultimately affects T-cell development, activation and differentiation.
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Affiliation(s)
- Clifford S Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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21
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Hsu LY, Tan YX, Xiao Z, Malissen M, Weiss A. A hypomorphic allele of ZAP-70 reveals a distinct thymic threshold for autoimmune disease versus autoimmune reactivity. ACTA ACUST UNITED AC 2009; 206:2527-41. [PMID: 19841086 PMCID: PMC2768860 DOI: 10.1084/jem.20082902] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
ZAP-70 is critical for T cell receptor (TCR) signaling. Tyrosine to phenylalanine mutations of Y315 and Y319 in ZAP-70 suggest these residues function to recruit downstream effector molecules, but mutagenesis and crystallization studies reveal that these residues also play an important role in autoinhibition ZAP-70. To address the importance of the scaffolding function, we generated a zap70 mutant mouse (YYAA mouse) with Y315 and Y319 both mutated to alanines. These YYAA mice reveal that the scaffolding function is important for normal development and function. Moreover, the YYAA mice have many similarities to a previously identified ZAP-70 mutant mouse, SKG, which harbors a distinct hypomorphic mutation. Both YYAA and SKG mice have impaired T cell development and hyporesponsiveness to TCR stimulation, markedly reduced numbers of thymic T regulatory cells and defective positive and negative selection. YYAA mice, like SKG mice, develop rheumatoid factor antibodies, but fail to develop autoimmune arthritis. Signaling differences that result from ZAP-70 mutations appear to skew the TCR repertoire in ways that differentially influence propensity to autoimmunity versus autoimmune disease susceptibility. By uncoupling the relative contribution from T regulatory cells and TCR repertoire during thymic selection, our data help to identify events that may be important, but alone are insufficient, for the development of autoimmune disease.
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Affiliation(s)
- Lih-Yun Hsu
- Department of Medicine, Rosalind Russell Medical Research Center for Arthritis, Howard Hughes Medical Institute, University of California San Francisco Children's Hospital, University of California, San Francisco, San Francisco, CA 94143, USA
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22
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Au-Yeung BB, Deindl S, Hsu LY, Palacios EH, Levin SE, Kuriyan J, Weiss A. The structure, regulation, and function of ZAP-70. Immunol Rev 2009; 228:41-57. [PMID: 19290920 DOI: 10.1111/j.1600-065x.2008.00753.x] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The tyrosine ZAP-70 (zeta-associated protein of 70 kDa) kinase plays a critical role in activating many downstream signal transduction pathways in T cells following T-cell receptor (TCR) engagement. The importance of ZAP-70 is evidenced by the severe combined immunodeficiency that occurs in ZAP-70-deficient mice and humans. In this review, we describe recent analyses of the ZAP-70 crystal structure, revealing a complex regulatory mechanism of ZAP-70 activity, the differential requirements for ZAP-70 and spleen tyrosine kinase (SyK) in early T-cell development, as well as the role of ZAP-70 in chronic lymphocytic leukemia and autoimmunity. Thus, the critical importance of ZAP-70 in TCR signaling and its predominantly T-cell-restricted expression pattern make ZAP-70 an attractive drug target for the inhibition of pathological T-cell responses in disease.
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Affiliation(s)
- Byron B Au-Yeung
- Department of Medicine, Rosalind Russell Medical Research Center for Arthritis, Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA 94143-0795, USA
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23
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Geahlen RL. Syk and pTyr'd: Signaling through the B cell antigen receptor. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2009; 1793:1115-27. [PMID: 19306898 DOI: 10.1016/j.bbamcr.2009.03.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 03/06/2009] [Indexed: 11/18/2022]
Abstract
The B cell receptor (BCR) transduces antigen binding into alterations in the activity of intracellular signaling pathways through its ability to recruit and activate the cytoplasmic protein-tyrosine kinase Syk. The recruitment of Syk to the receptor, its activation and its subsequent interactions with downstream effectors are all regulated by its phosphorylation on tyrosine. This review discusses our current understanding of how this phosphorylation regulates the activity of Syk and its participation in signaling through the BCR.
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Affiliation(s)
- Robert L Geahlen
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA.
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24
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Abstract
Little is known regarding the functional effects of common autoimmune susceptibility variants on human immune cells. The SNP CT60 (rs3087243; A/G) located in the 3' UTR of the CTLA4 gene has been associated with autoimmune diseases. We examined a cohort of healthy individuals stratified by genotypes at CTLA4 to gain insight into the functional effects of allelic variation on T cell signaling. Using phospho-site-specific mAbs, we tested the hypothesis that the CT60 genotype at CTLA4 is associated with altered T cell antigen receptor (TCR) signaling in naive and/or memory T cells. By normalizing for the extent of the initial TCR signaling event at CD3zeta, we observed that the relative responsiveness to TCR stimulation as assessed by phosphorylation levels of downstream signaling molecules was altered in naive (CD4(+)CD45RA(high)) and memory (CD4(+)CD45RA(low)) T cells obtained from individuals with the disease-susceptibility allele at CTLA4. Thus, allelic variation associated with autoimmune disease can alter the signaling threshold of CD4(+) T cells. These experiments provide a rational approach for the dissection of T cell-susceptibility genes in autoimmune diseases.
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25
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Deindl S, Kadlecek TA, Brdicka T, Cao X, Weiss A, Kuriyan J. Structural basis for the inhibition of tyrosine kinase activity of ZAP-70. Cell 2007; 129:735-46. [PMID: 17512407 DOI: 10.1016/j.cell.2007.03.039] [Citation(s) in RCA: 195] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 02/28/2007] [Accepted: 03/19/2007] [Indexed: 11/23/2022]
Abstract
ZAP-70, a cytoplasmic tyrosine kinase required for T cell antigen receptor signaling, is controlled by a regulatory segment that includes a tandem SH2 unit responsible for binding to immunoreceptor tyrosine-based activation motifs (ITAMs). The crystal structure of autoinhibited ZAP-70 reveals that the inactive kinase domain adopts a conformation similar to that of cyclin-dependent kinases and Src kinases. The autoinhibitory mechanism of ZAP-70 is, however, distinct and involves interactions between the regulatory segment and the hinge region of the kinase domain that reduce its flexibility. Two tyrosine residues in the SH2-kinase linker that activate ZAP-70 when phosphorylated are involved in aromatic-aromatic interactions that connect the linker to the kinase domain. These interactions are inconsistent with ITAM binding, suggesting that destabilization of this autoinhibited ZAP-70 conformation is the first step in kinase activation.
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Affiliation(s)
- Sebastian Deindl
- Department of Molecular and Cell Biology, Department of Chemistry, and Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
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26
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Swaminathan G, Tsygankov AY. The Cbl family proteins: ring leaders in regulation of cell signaling. J Cell Physiol 2006; 209:21-43. [PMID: 16741904 DOI: 10.1002/jcp.20694] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The proto-oncogenic protein c-Cbl was discovered as the cellular form of v-Cbl, a retroviral transforming protein. This was followed over the years by important discoveries, which identified c-Cbl and other Cbl-family proteins as key players in several signaling pathways. c-Cbl has donned the role of a multivalent adaptor protein, capable of interacting with a plethora of proteins, and has been shown to positively influence certain biological processes. The identity of c-Cbl as an E3 ubiquitin ligase unveiled the existence of an important negative regulatory pathway involved in maintaining homeostasis in protein tyrosine kinase (PTK) signaling. Recent years have also seen the emergence of novel regulators of Cbl, which have provided further insights into the complexity of Cbl-influenced pathways. This review will endeavor to provide a summary of current studies focused on the effects of Cbl proteins on various biological processes and the mechanism of these effects. The major sections of the review are as follows: Structure and genomic organization of Cbl proteins; Phosphorylation of Cbl; Interactions of Cbl; Localization of Cbl; Mechanism of effects of Cbl: (a) Ubiquitylation-dependent events: This section elucidates the mechanism of Cbl-mediated downregulation of EGFR and details the PTK and non-PTKs targeted by Cbl. In addition, it addresses the functional requirements for E3 Ubiquitin ligase activity of Cbl and negative regulation of Cbl-mediated downregulation of PTKs, (b) Adaptor functions: This section discusses the mechanisms of adaptor functions of Cbl in mitogen-activated protein kinase (MAPK) activation, insulin signaling, regulation of Ras-related protein 1 (Rap1), PI-3' kinase signaling, and regulation of Rho-family GTPases and cytoskeleton; Biological functions: This section gives an account of the diverse biological functions of Cbl and includes the role of Cbl in transformation, T-cell signaling and thymus development, B-cell signaling, mast-cell degranulation, macrophage functions, bone development, neurite growth, platelet activation, muscle degeneration, and bacterial invasion; Conclusions and perspectives.
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Affiliation(s)
- Gayathri Swaminathan
- Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
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27
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Gelkop S, Gish GD, Babichev Y, Pawson T, Isakov N. T cell activation-induced CrkII binding to the Zap70 protein tyrosine kinase is mediated by Lck-dependent phosphorylation of Zap70 tyrosine 315. THE JOURNAL OF IMMUNOLOGY 2006; 175:8123-32. [PMID: 16339550 DOI: 10.4049/jimmunol.175.12.8123] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The Zap70 protein tyrosine kinase controls TCR-linked signal transduction pathways and is critical for T cell development and responsiveness. Following engagement of TCR, the Zap70 undergoes phosphorylation on multiple tyrosine residues that are implicated in the regulation of its catalytic activity and interaction with signaling effector molecules downstream of the TCR. We have shown previously that the CT10 regulator of kinase II (CrkII) adapter protein interacts with tyrosine-phosphorylated Zap70 in TCR-engaged T cells, and now extend these studies to show that Tyr315 in the Zap70 interdomain B region is the site of interaction with CrkII. A point mutation of Tyr315 (Y315F) eliminated the CrkII-Zap70 interaction capacity. Phosphorylation of Tyr315 and Zap70 association with CrkII were both dependent upon the Lck protein tyrosine kinase. Previous studies demonstrated the Tyr315 is the Vav-Src homology 2 (SH2) binding site, and that replacement of Tyr315 by Phe impaired the function of Zap70 in TCR signaling. However, fluorescence polarization-based binding studies revealed that the CrkII-SH2 and the Vav-SH2 bind a phosphorylated Tyr315-Zap70-derived peptide with affinities of a similar order of magnitude (Kd of 2.5 and 1.02 microM, respectively). The results suggest therefore that the biological functions attributed to the association of Zap70 with Vav following T cell activation may equally reflect the association of Zap70 with CrkII, and further support a regulatory role for CrkII in the TCR-linked signal transduction pathway.
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Affiliation(s)
- Sigal Gelkop
- Department of Microbiology and Immunology, Faculty of Health Sciences, and the Cancer Research Center, Ben Gurion University of the Negev, Beer Sheva, Israel
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28
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Bartis D, Boldizsár F, Szabó M, Pálinkás L, Németh P, Berki T. Dexamethasone induces rapid tyrosine-phosphorylation of ZAP-70 in Jurkat cells. J Steroid Biochem Mol Biol 2006; 98:147-54. [PMID: 16406604 DOI: 10.1016/j.jsbmb.2005.01.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2005] [Revised: 07/12/2005] [Accepted: 09/19/2005] [Indexed: 12/18/2022]
Abstract
Steroid hormones are known to mediate rapid non-genomic effects occurring within minutes, besides the classical genomic actions mediated by the nuclear translocation of the cytoplasmic glucocorticoid receptor (GR). The glucocorticoid hormone (GC) has significant role in the regulation of T-cell activation; however, the cross-talk between the GC and T-cell receptor (TcR) signal transducing pathways are still to be elucidated. We examined the rapid effects of GC exposure on in vitro cultured human T-cells. Our results showed that Dexamethasone (DX), a GC analogue, when applied at high dose (10 microM), induced rapid (within 5 min) tyrosine-phosphorylation events in Jurkat cells. Short DX pre-treatment strongly inhibited the tyrosine-phosphorylation stimulated by CD3 cross-linking. Furthermore, we also investigated the phosphorylation status of ZAP-70, an important member of tyrosine kinase mediated signalling pathway of TcR-elicited T-cell activation. Here, we demonstrate that high dose DX induced a rapid ZAP-70 tyrosine-phosphorylation in Jurkat T-cells. DX-induced ZAP-70 phosphorylation could be inhibited by RU486 (GR antagonist), suggesting that this process was GR mediated. DX-induced ZAP-70 phosphorylation did not occur in the absence of active p56-lck as examined in the p56-lck kinase-deficient Jurkat cell line JCaM1.6. Our results show that DX, at a high dose, can rapidly influence the initial tyrosine-phosphorylation events of the CD3 signalling pathway in Jurkat cells, thereby modifying TcR-derived signals. Lck and ZAP-70 represent an important molecular link between the TcR and GC signalling pathways.
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Affiliation(s)
- Domokos Bartis
- University of Pécs, Faculty of Medicine, Department of Immunology and Biotechnology, Szigeti út 12, H-7643 Pécs, Hungary.
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29
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Groesch TD, Zhou F, Mattila S, Geahlen RL, Post CB. Structural basis for the requirement of two phosphotyrosine residues in signaling mediated by Syk tyrosine kinase. J Mol Biol 2005; 356:1222-36. [PMID: 16410013 DOI: 10.1016/j.jmb.2005.11.095] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2005] [Revised: 11/30/2005] [Accepted: 11/30/2005] [Indexed: 11/30/2022]
Abstract
The protein-tyrosine kinase Syk couples immune recognition receptors to multiple signal transduction pathways, including the mobilization of calcium and the activation of NFAT. The ability of Syk to regulate signaling is influenced by its phosphorylation on tyrosine residues within the linker B region. The phosphorylation of both Y342 and Y346 is necessary for optimal signaling from the B cell receptor for antigen. The SH2 domains of multiple signaling proteins share the ability to bind this doubly phosphorylated site. The NMR structure of the C-terminal SH2 domain of PLCgamma (PLCC) bound to a doubly phosphorylated Syk peptide reveals a novel mode of phosphotyrosine recognition. PLCC undergoes extensive conformational changes upon binding to form a second phosphotyrosine-binding pocket in which pY346 is largely desolvated and stabilized through electrostatic interactions. The formation of the second binding pocket is distinct from other modes of phosphotyrosine recognition in SH2-protein association. The dependence of signaling on simultaneous phosphorylation of these two tyrosine residues offers a new mechanism to fine-tune the cellular response to external stimulation.
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Affiliation(s)
- Teresa D Groesch
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue Cancer Center and Markey Center for Structural Biology, Purdue University, West Lafayette, IN 47907, USA
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30
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Davanture S, Leignadier J, Milani P, Soubeyran P, Malissen B, Malissen M, Schmitt-Verhulst AM, Boyer C. Selective defect in antigen-induced TCR internalization at the immune synapse of CD8 T cells bearing the ZAP-70(Y292F) mutation. THE JOURNAL OF IMMUNOLOGY 2005; 175:3140-9. [PMID: 16116204 DOI: 10.4049/jimmunol.175.5.3140] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Cbl proteins have been implicated in ligand-induced TCR/CD3 down-modulation, but underlying mechanisms are unclear. We analyzed the effect of mutation of a cbl-binding site on ZAP-70 (ZAP-Y292F) on dynamics, internalization, and degradation of the TCR/CD3 complex in response to distinct stimuli. Naive CD8 T cells expressing the P14 transgenic TCR from ZAP-Y292F mice were selectively affected in TCR/CD3 down-modulation in response to antigenic stimulation, whereas neither anti-CD3 Ab-, and PMA-induced TCR down-modulation, nor constitutive receptor endocytosis/cycling were impaired. We further established that the defect in TCR/CD3 down-modulation in response to Ag was paralleled by an impaired TCR/CD3 internalization and CD3zeta degradation. Analysis of T/APC conjugates revealed that delayed redistribution of TCR at the T/APC contact zone was paralleled by a delay in TCR internalization in the synaptic zone in ZAP-Y292F compared with ZAP-wild-type T cells. Cbl recruitment to the synapse was also retarded in ZAP-Y292F T cells, although F-actin and LFA-1 redistribution was similar for both cell types. This study identifies a step involving ZAP-70/cbl interaction that is critical for rapid internalization of the TCR/CD3 complex at the CD8 T cell/APC synapse.
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Affiliation(s)
- Suzel Davanture
- Centre d'Immunologie de Marseille-Luminy, Centre National de la Recherche Scientifique/Institut National de la Santé et de la Recherche Médicale/Université de la Méditerranée, Marseille, Cedex, France
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31
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Brdicka T, Kadlecek TA, Roose JP, Pastuszak AW, Weiss A. Intramolecular regulatory switch in ZAP-70: analogy with receptor tyrosine kinases. Mol Cell Biol 2005; 25:4924-33. [PMID: 15923611 PMCID: PMC1140569 DOI: 10.1128/mcb.25.12.4924-4933.2005] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ZAP-70, a Syk family cytoplasmic protein tyrosine kinase (PTK), is required to couple the activated T-cell antigen receptor (TCR) to downstream signaling pathways. It contains two tandem SH2 domains that bind to phosphorylated TCR subunits and a C-terminal catalytic domain. The region connecting the SH2 domains with the kinase domain, termed interdomain B, has previously been shown to have striking regulatory effects on ZAP-70 function, presumed to be due to the recruitment of key substrates. Paradoxically, deletion of interdomain B preserves ZAP-70 function. Recent structural studies of several receptor tyrosine kinases (RTKs) revealed that their juxtamembrane regions negatively regulate their catalytic activities. In EphB2 and several other RTKs, this autoinhibition depends upon interaction between the kinase domain and tyrosine residues within the juxtamembrane region. Autoinhibition is released when these tyrosines become phosphorylated following receptor stimulation. Sequence homology suggested analogous regulation for ZAP-70. Based on mutagenesis analysis of ZAP-70 interdomain B, we find that this region downregulates ZAP-70 catalytic activity in a similar manner as the juxtamembrane region of EphB2. Similar regulation was also noted for the related Syk kinase. These findings suggest that a general autoinhibitory mechanism employed by RTKs is also used by some cytoplasmic tyrosine kinases.
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Affiliation(s)
- Tomas Brdicka
- Department of Medicine, The Rosalind Russell Medical Research Center for Arthritis and Howard Hughes Medical Institute, University of California at San Francisco, 533 Parnassus Avenue, San Francisco, CA 94143-0795, USA
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32
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Qu X, Kawauchi-Kamata K, Miah SMS, Hatani T, Yamamura H, Sada K. Tyrosine phosphorylation of adaptor protein 3BP2 induces T cell receptor-mediated activation of transcription factor. Biochemistry 2005; 44:3891-8. [PMID: 15751964 DOI: 10.1021/bi048353o] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Molecular adaptors/scaffolds have indispensable roles in the activation of lymphocytes. In this report, we have demonstrated the role of tyrosine phosphorylation of an adaptor protein 3BP2 (c-Abl-SH3 domain binding protein-2, also known as SH3BP2) in T cell receptor (TCR)-mediated activation of transcription factor. Short interfering RNA for 3BP2 suppresses the expression level of endogenous 3BP2 and inhibits TCR-mediated activation of interleukin (IL)-2 promoter and nuclear factor of activated T cells (NFAT) element. Engagement of TCR induces tyrosine phosphorylation and lipid raft translocation of 3BP2. The overexpression studies reveal that substitution of 3BP2-Tyr(183), Tyr(446), or Arg(486) in the SH2 domain suppresses TCR-mediated activation of NFAT. Point mutations of 3BP2 cannot affect the translocation of 3BP2 into the lipid raft. Phosphorylation of Tyr(183) is required for the interaction with Vav1, the guanine nucleotide exchanging factor of Rac1. In fact, overexpression of dominant-negative form of Rac1 inhibits TCR-mediated activation of NFAT. Phosphorylation of Tyr(446) recruits the SH2 domain of Lck for the optimal activation of transcription factors. Furthermore, point mutation of Arg(486) in the 3BP2-SH2 domain that couples ZAP-70 to LAT dramatically reduces NFAT activation. These results suggest that the site-directed functions of 3BP2 induce the activation of transcription factors.
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MESH Headings
- Adaptor Proteins, Signal Transducing/antagonists & inhibitors
- Adaptor Proteins, Signal Transducing/genetics
- Adaptor Proteins, Signal Transducing/metabolism
- Adaptor Proteins, Signal Transducing/physiology
- Amino Acid Substitution/genetics
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- DNA-Binding Proteins/antagonists & inhibitors
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Homeodomain Proteins/antagonists & inhibitors
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Homeodomain Proteins/physiology
- Humans
- Interleukin-2/antagonists & inhibitors
- Interleukin-2/genetics
- Interleukin-2/metabolism
- Jurkat Cells
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/genetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/metabolism
- Membrane Microdomains/genetics
- Membrane Microdomains/metabolism
- NFATC Transcription Factors
- Nuclear Proteins/antagonists & inhibitors
- Nuclear Proteins/genetics
- Nuclear Proteins/metabolism
- Phosphorylation
- Promoter Regions, Genetic
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins/metabolism
- Proto-Oncogene Proteins c-vav
- RNA, Small Interfering/chemistry
- RNA-Binding Proteins
- Receptors, Antigen, T-Cell/antagonists & inhibitors
- Receptors, Antigen, T-Cell/physiology
- Transcription Factors/antagonists & inhibitors
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcriptional Activation/genetics
- Transfection
- Tyrosine/genetics
- Tyrosine/metabolism
- src Homology Domains/genetics
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Affiliation(s)
- Xiujuan Qu
- Division of Proteomics, Department of Genome Sciences, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
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33
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Ikehara Y, Ikehara SK, Paulson JC. Negative regulation of T cell receptor signaling by Siglec-7 (p70/AIRM) and Siglec-9. J Biol Chem 2004; 279:43117-25. [PMID: 15292262 DOI: 10.1074/jbc.m403538200] [Citation(s) in RCA: 144] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Siglec-7 (p70/AIRM) and Siglec-9 are "CD33"-related siglecs expressed on natural killer (NK) cells and subsets of peripheral T cells. Like other inhibitory NK cell receptors, they contain immunoglobulin receptor family tyrosine-based inhibitory motifs in their cytoplasmic domains, and Siglec-7 has been demonstrated to negatively regulate NK cell activation. Based on reports of the presence of these siglecs on T cells, we sought to determine if they are capable of modulating T cell receptor (TCR) signaling using Jurkat T cells stably and transiently transfected with Siglec-7 or Siglec-9. Following either pervanadate stimulation or TCR engagement, both Siglecs exhibited increased tyrosine phosphorylation and recruitment of SHP-1. Effects of Siglec-7 and -9 were also evident in downstream events in the signaling pathway. Both siglecs reduced phosphorylation of Tyr319 on ZAP-70, known to play a pivotal role in up-regulation of gene transcription following TCR stimulation. There was also a corresponding decreased transcriptional activity of nuclear factor of activated T cells (NFAT) as determined using a luciferase reporter gene. Like all siglecs, Siglec-7 and -9 recognize sialic acid-containing glycans of glycoproteins and glycolipids as ligands. Mutation of the conserved Arg in the ligand binding site of Siglec-7 (Arg124) or Siglec-9 (Arg120) resulted in reduced inhibitory function in the NFAT/luciferase transcription assay, suggesting that ligand binding is required for optimal inhibition of TCR signaling. The combined results demonstrate that both Siglec-7 and Siglec-9 are capable of negative regulation of TCR signaling and that ligand binding is required for optimal activity.
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MESH Headings
- Amino Acid Motifs
- Antigens, CD/chemistry
- Antigens, CD/metabolism
- Antigens, CD/physiology
- Antigens, Differentiation, Myelomonocytic/chemistry
- Antigens, Differentiation, Myelomonocytic/metabolism
- Antigens, Differentiation, Myelomonocytic/physiology
- Blotting, Western
- Cell Separation
- Cytoplasm/metabolism
- Dose-Response Relationship, Drug
- Enzyme Activation
- Enzyme Inhibitors/pharmacology
- Flow Cytometry
- Genes, Reporter
- Humans
- Immunoprecipitation
- Jurkat Cells
- Lectins/metabolism
- Lectins/physiology
- Ligands
- Luciferases/metabolism
- Microscopy, Fluorescence
- Models, Biological
- Phosphorylation
- Protein Binding
- Protein Structure, Tertiary
- Protein-Tyrosine Kinases/chemistry
- Sialic Acid Binding Ig-like Lectin 3
- Sialic Acid Binding Immunoglobulin-like Lectins
- Signal Transduction
- T-Lymphocytes/metabolism
- Time Factors
- Transcription, Genetic
- Transcriptional Activation
- Transfection
- Tyrosine/chemistry
- Vanadates/chemistry
- ZAP-70 Protein-Tyrosine Kinase
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Affiliation(s)
- Yuzuru Ikehara
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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34
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Steinberg M, Adjali O, Swainson L, Merida P, Di Bartolo V, Pelletier L, Taylor N, Noraz N. T-cell receptor–induced phosphorylation of the ζ chain is efficiently promoted by ZAP-70 but not Syk. Blood 2004; 104:760-7. [PMID: 15059847 DOI: 10.1182/blood-2003-12-4314] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractEngagement of the T-cell receptor (TCR) results in the activation of Lck/Fyn and ZAP-70/Syk tyrosine kinases. Lck-mediated tyrosine phosphorylation of signaling motifs (ITAMs) in the CD3-ζ subunits of the TCR is an initial step in the transduction of signaling cascades. However, ζ phosphorylation is also promoted by ZAP-70, as TCR-induced ζ phosphorylation is defective in ZAP-70–deficient T cells. We show that this defect is corrected by stable expression of ZAP-70, but not Syk, in primary and transformed T cells. Indeed, these proteins are differentially coupled to the TCR with a 5- to 10-fold higher association of ZAP-70 with ζ as compared to Syk. Low-level Syk-ζ binding is associated with significantly less Lck coupled to the TCR. Moreover, diminished coupling of Lck to ζ correlates with a poor phosphorylation of the positive regulatory tyr352 residue of Syk. Thus, recruitment of Lck into the TCR complex with subsequent ζ chain phosphorylation is promoted by ZAP-70 but not Syk. Importantly, the presence of ZAP-70 positively regulates the TCR-induced tyrosine phosphorylation of Syk. The interplay between Syk and ZAP-70 in thymocytes, certain T cells, and B-chronic lymphocytic leukemia cells, in which they are coexpressed, will therefore modulate the amplitude of antigen-mediated receptor signaling.
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Affiliation(s)
- Marcos Steinberg
- Institut de Génétique Moléculaire de Montpellier, Centre National de la Recherche Scientifique Unité de Recherches 5535/Institut Fédératife de Recherche, F-34293 Montpellier 5, France
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35
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Abstract
Regulation of tyrosine kinase-mediated cellular activation through antigen receptors is of great biological and practical significance. The evolutionarily conserved Cbl family ubiquitin ligases have emerged as key negative regulators of activated tyrosine kinase-coupled receptors, and their impaired function switches a normal immune response into autoimmunity. Cbl proteins facilitate the ubiquitinylation of activated tyrosine kinases and other signaling proteins and of the signaling chains of receptors themselves; monoubiquitin tag promotes sorting of activated receptors and associated proteins into internal vesicles of the multivesicular body, facilitating their lysosomal degradation, whereas polyubiquitin tag promotes proteasomal degradation. Notably, increased expression of Cbl proteins and other ubiquitin ligases is a component of anergic signaling program in T cells. Thus, controlled destruction of the signaling apparatus has emerged as a key to fine-tuning antigen receptor signaling. Further studies of this pathway are likely to elucidate the pathogenesis of autoimmune diseases and offer new therapeutic targets.
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Affiliation(s)
- Lei Duan
- Division of Molecular Oncology, Department of Medicine, Evanston Northwestern Healthcare Research Institute, Feinberg School of Medicine, Northwestern University, IL 60201, USA
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36
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Goda S, Quale AC, Woods ML, Felthauser A, Shimizu Y. Control of TCR-Mediated Activation of β1 Integrins by the ZAP-70 Tyrosine Kinase Interdomain B Region and the Linker for Activation of T Cells Adapter Protein. THE JOURNAL OF IMMUNOLOGY 2004; 172:5379-87. [PMID: 15100278 DOI: 10.4049/jimmunol.172.9.5379] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
One of the earliest functional responses of T lymphocytes to extracellular signals that activate the Ag-specific CD3/TCR complex is a rapid, but reversible, increase in the functional activity of integrin adhesion receptors. Previous studies have implicated the tyrosine kinase zeta-associated protein of 70 kDa (ZAP-70) and the lipid kinase phosphatidylinositol 3-kinase, in the activation of beta(1) integrins by the CD3/TCR complex. In this report, we use human ZAP-70-deficient Jurkat T cells to demonstrate that the kinase activity of ZAP-70 is required for CD3/TCR-mediated increases in beta(1) integrin-mediated adhesion and activation of phosphatidylinositol 3-kinase. A tyrosine to phenylalanine substitution at position 315 in the interdomain B of ZAP-70 inhibits these responses, whereas a similar substitution at position 292 enhances these downstream signals. These mutations in the ZAP-70 interdomain B region also specifically affect CD3/TCR-mediated tyrosine phosphorylation of residues 171 and 191 in the cytoplasmic domain of the linker for activation of T cells (LAT) adapter protein. CD3/TCR signaling to beta(1) integrins is defective in LAT-deficient Jurkat T cells, and can be restored with expression of wild-type LAT. Mutant LAT constructs with tyrosine to phenylalanine substitutions at position 171 and/or position 191 do not restore CD3/TCR-mediated activation of beta(1) integrins in LAT-deficient T cells. Thus, these studies demonstrate that the interdomain B region of ZAP-70 regulates beta(1) integrin activation by the CD3/TCR via control of tyrosine phosphorylation of tyrosine residues 171 and 191 in the LAT cytoplasmic domain.
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Affiliation(s)
- Seiji Goda
- Department of Laboratory Medicine and Pathology, Center for Immunology, Cancer Center, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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37
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Zhong L, Wu CH, Lee WH, Liu CP. ζ-Associated Protein of 70 kDa (ZAP-70), but Not Syk, Tyrosine Kinase Can Mediate Apoptosis of T Cells through the Fas/Fas Ligand, Caspase-8 and Caspase-3 Pathways. THE JOURNAL OF IMMUNOLOGY 2004; 172:1472-82. [PMID: 14734724 DOI: 10.4049/jimmunol.172.3.1472] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The TCR zeta-chain-associated protein of 70 kDA (ZAP-70) and Syk tyrosine kinases play critical roles in regulating TCR-mediated signal transduction. They not only share some overlapped functions but also may play unique roles in regulating the function and development of T cells. However, it is not known whether they have different effects on the activation and activation-induced cell death of T cells. To address this question, we generated cDNAs encoding chimeric molecules that a tailless TCR zeta-chain was directly linked to truncated ZAP-70 (Z/ZAP) or Syk (Z/Syk) molecules lacking the two Src homology 2 domains. Transfection of these molecules into zeta-chain-deficient cells restored their TCR expression. In addition, Z/ZAP and Z/Syk transfectants but not control cells demonstrated kinase activities in phosphorylating an exogenous substrate specific for ZAP-70 and Syk kinases. Z/ZAP transfectants activated through TCRs underwent a faster time course of apoptosis and had a greater percentage of apoptotic cells than that of Z/Syk and control cells. Activated Z/ZAP transfectants increased Fas and Fas ligand (FasL) expression 3- and 40-fold, respectively. Blocking of the Fas/FasL interaction could inhibit the apoptosis of Z/ZAP transfectants. In contrast, although activated Z/Syk transfectants could increase FasL expression, their Fas expression actually decreased and the percentage of apoptotic cells did not increase. Further studies of the mechanisms revealed that activation of Z/ZAP but not Z/Syk transfectants resulted in rapid activation of caspase-3 and caspase-8 that could also be inhibited by blocking Fas/FasL interaction. These results demonstrated that ZAP-70 and Syk play distinct roles in T cell activation and activation-induced cell death.
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Affiliation(s)
- Lingwen Zhong
- Division of Immunology, Beckman Research Institute, City of Hope, Duarte, CA 91010, USA
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38
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Rodríguez-Borlado L, Barber DF, Hernández C, Rodríguez-Marcos MA, Sánchez A, Hirsch E, Wymann M, Martínez-A C, Carrera AC. Phosphatidylinositol 3-kinase regulates the CD4/CD8 T cell differentiation ratio. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:4475-82. [PMID: 12707323 DOI: 10.4049/jimmunol.170.9.4475] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The signaling pathways that control T cell differentiation have only begun to be elucidated. Using T cell lines, it has been shown that class IA phosphatidylinositol 3-kinase (PI3K), a heterodimer composed of a p85 regulatory and a p110 catalytic subunit, is activated after TCR stimulation. Nonetheless, the contribution of p85/p110 PI3K isoforms in T cell development has not been described. Mice deficient in the other family of class I PI3K, p110gamma, which is regulated by G protein-coupled receptors, exhibit reduced thymus size. Here we examine T cell development in p110gamma-deficient mice and in mice expressing an activating mutation of the p85 regulatory subunit, p65(PI3K), in T cells. We show that p110gamma-deficient mice have a partial defect in pre-TCR-dependent differentiation, which is restored after expression of the p65(PI3K) activating mutation. Genetic alteration of both PI3K isoforms also affects positive selection; p110gamma deletion decreased and p65(PI3K) expression augmented the CD4(+)/CD8(+) differentiation ratio. Finally, data are presented showing that both PI3K isoforms influenced mature thymocyte migration to the periphery. These observations underscore the contribution of PI3K in T cell development, as well as its implication in determining the CD4(+)/CD8(+) T cell differentiation ratio in vivo.
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Affiliation(s)
- Luis Rodríguez-Borlado
- Department of Immunology and Oncology, Centro Nacional de Biotecnología, Universidad Autónoma, Cantoblanco, Madrid, Spain
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39
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Thien CBF, Scaife RM, Papadimitriou JM, Murphy MA, Bowtell DDL, Langdon WY. A mouse with a loss-of-function mutation in the c-Cbl TKB domain shows perturbed thymocyte signaling without enhancing the activity of the ZAP-70 tyrosine kinase. J Exp Med 2003; 197:503-13. [PMID: 12591907 PMCID: PMC2193865 DOI: 10.1084/jem.20021498] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The unique tyrosine kinase binding (TKB) domain of Cbl targets phosphorylated tyrosines on activated protein tyrosine kinases (PTKs); this targeting is considered essential for Cbl proteins to negatively regulate PTKs. Here, a loss-of-function mutation (G304E) in the c-Cbl TKB domain, first identified in Caenorhabditis elegans, was introduced into a mouse and its effects in thymocytes and T cells were studied. In marked contrast to the c-Cbl knockout mouse, we found no evidence of enhanced activity of the ZAP-70 PTK in thymocytes from the TKB domain mutant mouse. This finding contradicts the accepted mechanism of c-Cbl-mediated negative regulation, which requires TKB domain targeting of phosphotyrosine 292 in ZAP-70. However, the TKB domain mutant mouse does show aspects of enhanced signaling that parallel those of the c-Cbl knockout mouse, but these involve the constitutive activation of Rac and not enhanced PTK activity. Furthermore, the enhanced signaling in CD4(+)CD8(+) double positive thymocytes appears to be compensated by the selective down-regulation of CD3 on mature thymocytes and peripheral T cells from both strains of mutant c-Cbl mice.
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Affiliation(s)
- Christine B F Thien
- Department of Pathology, University of Western Australia, Crawley, WA 6009, Australia
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40
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Abstract
Immature double positive (DP) thymocytes bearing a T cell receptor (TCR) that interacts with self-major histocompatibility complex (MHC) molecules receive signals that induce either their differentiation (positive selection) or apoptosis (negative selection). Furthermore, those cells that are positively selected develop into two different lineages, CD4 or CD8, depending on whether their TCRs bind to MHC class II or I, respectively. Positive selection therefore involves rescue from the default fate (death), lineage commitment, and progression to the single positive (SP) stage. These are probably temporally distinct events that may require both unique and overlapping signals. Work in the past several years has started to unravel the signaling networks that control these processes. One of the first pathways identified as important for positive selection was Ras and its downstream effector, the Erk mitogen-activated protein kinase (MAPK) cascade. In this review we examine the factors that connect the TCR to the Ras/Erk cascade in DP thymocytes, as well as what we know about the downstream effectors of the Ras/Erk cascade important for positive selection. We also consider the possible role of this cascade in CD4/CD8 lineage development, and the possible interactions of the Ras/Erk cascade with Notch during these cell fate determination processes.
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Affiliation(s)
- José Alberola-Ila
- Division of Biology, California Institute of Technology, Pasadena, CA 91125, USA.
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41
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Abstract
After a brief overview of the themes and variations that occur in the family of receptors containing immunoreceptor tyrosine-based activation motifs (ITAMs), and of recent structural data on the ligand-binding subunits of these receptors, we use these data to revisit how information on the state and quality of occupancy of the binding site of the T cell antigen receptor (TCR) is conveyed to the proximal components of the TCR transduction cassette.
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Affiliation(s)
- Bernard Malissen
- Centre d'Immunologie INSERM-CNRS de Marseille-Luminy, Marseille, France.
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42
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Folmer RHA, Geschwindner S, Xue Y. Crystal structure and NMR studies of the apo SH2 domains of ZAP-70: two bikes rather than a tandem. Biochemistry 2002; 41:14176-84. [PMID: 12450381 DOI: 10.1021/bi026465e] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The protein kinase ZAP-70 is involved in T-cell activation, and interacts with tyrosine-phosphorylated peptide sequences known as immunoreceptor tyrosine activation motifs (ITAMs), which are present in three of the subunits of the T-cell receptor. We have studied the tandem SH2 (tSH2) domains of ZAP-70, by both X-ray and NMR. Here, we present the crystal structure of the apoprotein, i.e., the tSH2 domain in the absence of ITAM. Comparison with the previously reported complex structure reveals that binding to the ITAM peptide induces surprisingly large movements between the two SH2 domains and within the actual binding sites. The conformation of the ITAM-free protein is partly governed by a hydrophobic cluster between the linker region and the C-terminal SH2 domain. Our data suggest that the two SH2 domains are able to undergo large interdomain movements. The proposed relative flexibility of the SH2 domains is further supported by the finding that no NMR signals could be detected for the two helices connecting the SH2 domains; these are likely to be broadened beyond detection due to conformational exchange. It is likely that this conformational reorientation induced by ITAM binding is the main signaling event activating the kinase domain in ZAP-70. Another NMR observation was that the N-terminal SH2 domain could bind tetrapeptides derived from the ITAM sequence, apparently without the need to interact with the C-terminal domain. In contrast, the C-terminal domain has little affinity for tetrapeptides. The opposite situation is true for binding to plain phosphotyrosine, where the C-terminal domain has a higher affinity. Distinct features in the crystal structure, showing the interdependence of both domains, explain these binding data.
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Affiliation(s)
- Rutger H A Folmer
- Structural Chemistry Laboratory, AstraZeneca R&D Mölndal, S-431 83 Mölndal, Sweden
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43
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Zhang J, Berenstein E, Siraganian RP. Phosphorylation of Tyr342 in the linker region of Syk is critical for Fc epsilon RI signaling in mast cells. Mol Cell Biol 2002; 22:8144-54. [PMID: 12417718 PMCID: PMC134060 DOI: 10.1128/mcb.22.23.8144-8154.2002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The linker region of Syk and ZAP70 tyrosine kinases plays an important role in regulating their function. There are three conserved tyrosines in this linker region; Tyr317 of Syk and its equivalent residue in ZAP70 were previously shown to negatively regulate the function of Syk and ZAP70. Here we studied the roles of the other two tyrosines, Tyr342 and Tyr346 of Syk, in Fc epsilon RI-mediated signaling. Antigen stimulation resulted in Tyr342 phosphorylation in mast cells. Syk with Y342F mutation failed to reconstitute Fc epsilon RI-initiated histamine release. In the Syk Y342F-expressing cells there was dramatically impaired receptor-induced phosphorylation of multiple signaling molecules, including LAT, SLP-76, phospholipase C-gamma2, but not Vav. Compared to wild-type Syk, Y342F Syk had decreased binding to phosphorylated immunoreceptor tyrosine-based activation motifs and reduced kinase activity. Surprisingly, mutation of Tyr346 had much less effect on Fc epsilon RI-dependent mast cell degranulation. An anti-Syk-phospho-346 tyrosine antibody indicated that antigen stimulation induced only a very minor increase in the phosphorylation of this tyrosine. Therefore, Tyr342, but not Tyr346, is critical for regulating Syk in mast cells and the function of these tyrosines in immune receptor signaling appears to be different from what has been previously reported for the equivalent residues of ZAP70.
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Affiliation(s)
- Juan Zhang
- Receptors and Signal Transduction Section, Oral Infection and Immunity Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA.
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44
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Werlen G, Palmer E. The T-cell receptor signalosome: a dynamic structure with expanding complexity. Curr Opin Immunol 2002; 14:299-305. [PMID: 11973126 DOI: 10.1016/s0952-7915(02)00339-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Signal transduction in T cells is a dynamic process involving a large number of membrane and cytosolic proteins. The TCR macromolecular complex (signalosome) is initiated by receptor occupancy and becomes more elaborate over time. This review describes how 'vertical' displacement mechanisms and lateral coalescence of lipid-raft-associated scaffold proteins combine to form distinct signalosomes, which control signal specificity.
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Affiliation(s)
- Guy Werlen
- Laboratory of Transplantation Immunology and Nephrology, Department of Research, University Hospital-Basel, Hebelstrasse 20, CH-4031, Basel, Switzerland.
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Rao N, Dodge I, Band H. The Cbl family of ubiquitin ligases: critical negative regulators of tyrosine kinase signaling in the immune system. J Leukoc Biol 2002. [DOI: 10.1189/jlb.71.5.753] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Navin Rao
- Division of Medical Sciences, Boston, Massachusetts
| | - Ingrid Dodge
- Division of Medical Sciences, Boston, Massachusetts
| | - Hamid Band
- Lymphocyte Biology Section, Division of Rheumatology, Immunology and Allergy, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts
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Di Bartolo V, Malissen M, Dufour E, Sechet E, Malissen B, Acuto O. Tyrosine 315 determines optimal recruitment of ZAP-70 to the T cell antigen receptor. Eur J Immunol 2002; 32:568-75. [PMID: 11828374 DOI: 10.1002/1521-4141(200202)32:2<568::aid-immu568>3.0.co;2-q] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recruitment of ZAP-70 protein tyrosine kinase to the T cell antigen receptor (TCR) is mediated by the binding of the SH2 domains of this enzyme to phosphorylated ITAM motifs in the CD3 and TCRzeta subunits. We have previously shown that the efficiency of both positive and negative thymocyte selection was decreased in knock-in mice expressing ZAP-70 mutated at Tyr315 (ZAP-70-Y315F), a residue laying in the interdomain B of this protein. Surprisingly, in these cells the amount of phosphorylated TCRzeta chain co-precipitating with ZAP-70-Y315F was significantly reduced compared to control mice. We report now that the binding affinity of ZAP-70-Y315F to phosphorylated ITAM is reduced as compared to the wild-type protein, whereas the intrinsic catalytic activity is untouched. Consequently, phosphorylated ITAM appear to be more accessible to protein tyrosine phosphatases (PTP) and can be readily dephosphorylated. We provide evidence suggesting that the defective ITAM binding induced by Tyr315 mutation is independent of the putative role of this residue as a binding site for Vav-1. Finally, we found that the extracellular signal-regulated kinase pathway is impaired in ZAP-70-Y315F-expressing mice. Collectively, these results demonstrate that Tyr315 has an unsuspected structural role in ZAP-70 and may allosterically regulate the function of the nearby SH2 domains.
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Affiliation(s)
- Vincenzo Di Bartolo
- Molecular Immunology Unit, Department of Immunology, Institut Pasteur, 25 Rue du Docteur Roux, F-75724 Paris Cedex 15, France.
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Gong Q, Jin X, Akk AM, Foger N, White M, Gong G, Wardenburg JB, Chan AC. Requirement for tyrosine residues 315 and 319 within zeta chain-associated protein 70 for T cell development. J Exp Med 2001; 194:507-18. [PMID: 11514606 PMCID: PMC2193491 DOI: 10.1084/jem.194.4.507] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Engagement of the T cell antigen receptor (TCR) induces the transphosphorylation of the zeta chain-associated protein of 70,000 Mr (ZAP-70) protein tyrosine kinase (PTK) by the CD4/8 coreceptor associated Lck PTK. Phosphorylation of Tyr 493 within ZAP-70's activation loop results in the enzymatic activation of ZAP-70. Additional tyrosines (Tyrs) within ZAP-70 are phosphorylated that play both positive and negative regulatory roles in TCR function. Phosphorylation of Tyr residues (Tyrs 315 and 319) within the Interdomain B region of the ZAP-70 PTK plays important roles in the generation of second messengers after TCR engagement. Here, we demonstrate that phosphorylation of these two Tyr residues also play important roles in mediating the positive and negative selection of T cells in the thymus.
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Affiliation(s)
- Qian Gong
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110
| | - Xiaohua Jin
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Antonina M. Akk
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Niko Foger
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110
| | - Mike White
- Center for Immunology, Department of Medicine
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110
| | - Guoqing Gong
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Julie Bubeck Wardenburg
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
| | - Andrew C. Chan
- Center for Immunology, Department of Medicine
- Division of Rheumatology, Department of Medicine
- Howard Hughes Medical Institute, Washington University School of Medicine, St. Louis, MO 63110
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