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Perico L, Casiraghi F, Sônego F, Todeschini M, Corna D, Cerullo D, Pezzotta A, Isnard-Petit P, Faravelli S, Forneris F, Thiam K, Benigni A, Remuzzi G. Bi-specific autoantigen-T cell engagers as targeted immunotherapy for autoreactive B cell depletion in autoimmune diseases. Front Immunol 2024; 15:1335998. [PMID: 38469301 PMCID: PMC10926275 DOI: 10.3389/fimmu.2024.1335998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 02/07/2024] [Indexed: 03/13/2024] Open
Abstract
Introduction In autoimmune diseases, autoreactive B cells comprise only the 0.1-0.5% of total circulating B cells. However, current first-line treatments rely on non-specific and general suppression of the immune system, exposing patients to severe side effects. For this reason, identification of targeted therapies for autoimmune diseases is an unmet clinical need. Methods Here, we designed a novel class of immunotherapeutic molecules, Bi-specific AutoAntigen-T cell Engagers (BiAATEs), as a potential approach for targeting the small subset of autoreactive B cells. To test this approach, we focused on a prototype autoimmune disease of the kidney, membranous nephropathy (MN), in which phospholipase A2 receptor (PLA2R) serves as primary nephritogenic antigen. Specifically, we developed a BiAATE consisting of the immunodominant Cysteine-Rich (CysR) domain of PLA2R and the single-chain variable fragment (scFv) of an antibody against the T cell antigen CD3, connected by a small flexible linker. Results BiAATE creates an immunological synapse between autoreactive B cells bearing an CysR-specific surface Ig+ and T cells. Ex vivo, the BiAATE successfully induced T cell-dependent depletion of PLA2R-specific B cells isolated form MN patients, sparing normal B cells. Systemic administration of BiAATE to mice transgenic for human CD3 reduced anti-PLA2R antibody levels following active immunization with PLA2R. Discussion Should this approach be confirmed for other autoimmune diseases, BiAATEs could represent a promising off-the-shelf therapy for precision medicine in virtually all antibody-mediated autoimmune diseases for which the pathogenic autoantigen is known, leading to a paradigm shift in the treatment of these diseases.
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Affiliation(s)
- Luca Perico
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Federica Casiraghi
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | | | - Marta Todeschini
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Daniela Corna
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Domenico Cerullo
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Anna Pezzotta
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | | | - Silvia Faravelli
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Federico Forneris
- The Armenise-Harvard Laboratory of Structural Biology, Department of Biology and Biotechnology, University of Pavia, Pavia, Italy
| | - Kader Thiam
- Preclinical Models & Services, genOway, Lyon, France
| | - Ariela Benigni
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
| | - Giuseppe Remuzzi
- Department of Molecular Medicine, Istituto di Ricerche Farmacologiche Mario Negri IRCCS, Bergamo, Italy
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2
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Manolios N, Pham S, Hou G, Du J, Quek C, Hibbs D. Non-Antigenic Modulation of Antigen Receptor (TCR) Cβ-FG Loop Modulates Signalling: Implications of External Factors Influencing T-Cell Responses. Int J Mol Sci 2023; 24:ijms24119334. [PMID: 37298286 DOI: 10.3390/ijms24119334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
T-cell recognition of antigens is complex, leading to biochemical and cellular events that impart both specific and targeted immune responses. The end result is an array of cytokines that facilitate the direction and intensity of the immune reaction-such as T-cell proliferation, differentiation, macrophage activation, and B-cell isotype switching-all of which may be necessary and appropriate to eliminate the antigen and induce adaptive immunity. Using in silico docking to identify small molecules that putatively bind to the T-cell Cβ-FG loop, we have shown in vitro using an antigen presentation assay that T-cell signalling is altered. The idea of modulating T-cell signalling independently of antigens by directly targeting the FG loop is novel and warrants further study.
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Affiliation(s)
- Nicholas Manolios
- Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
- Department of Rheumatology, Westmead Hospital, Sydney, NSW 2145, Australia
| | - Son Pham
- Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Guojiang Hou
- Department of Rheumatology, Westmead Hospital, Sydney, NSW 2145, Australia
| | - Jonathan Du
- The University of Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - Camelia Quek
- Sydney Medical School, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
| | - David Hibbs
- The University of Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW 2006, Australia
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3
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Lidström T, Cumming J, Gaur R, Frängsmyr L, Pateras IS, Mickert MJ, Franklin O, Forsell MN, Arnberg N, Dongre M, Patthey C, Öhlund D. Extracellular Galectin 4 Drives Immune Evasion and Promotes T-cell Apoptosis in Pancreatic Cancer. Cancer Immunol Res 2023; 11:72-92. [PMID: 36478037 PMCID: PMC9808371 DOI: 10.1158/2326-6066.cir-21-1088] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 07/19/2022] [Accepted: 11/08/2022] [Indexed: 12/13/2022]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is characterized by rich deposits of extracellular matrix (ECM), affecting the pathophysiology of the disease. Here, we identified galectin 4 (gal 4) as a cancer cell-produced protein that was deposited into the ECM of PDAC tumors and detected high-circulating levels of gal 4 in patients with PDAC. In orthotopic transplantation experiments, we observed increased infiltration of T cells and prolonged survival in immunocompetent mice transplanted with cancer cells with reduced expression of gal 4. Increased survival was not observed in immunodeficient RAG1-/- mice, demonstrating that the effect was mediated by the adaptive immune system. By performing single-cell RNA-sequencing, we found that the myeloid compartment and cancer-associated fibroblast (CAF) subtypes were altered in the transplanted tumors. Reduced gal 4 expression associated with a higher proportion of myofibroblastic CAFs and reduced numbers of inflammatory CAFs. We also found higher proportions of M1 macrophages, T cells, and antigen-presenting dendritic cells in tumors with reduced gal 4 expression. Using a coculture system, we observed that extracellular gal 4 induced apoptosis in T cells by binding N-glycosylation residues on CD3ε/δ. Hence, we show that gal 4 is involved in immune evasion and identify gal 4 as a promising drug target for overcoming immunosuppression in PDAC.
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Affiliation(s)
- Tommy Lidström
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.,Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Joshua Cumming
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.,Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Rahul Gaur
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.,Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Lars Frängsmyr
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Ioannis S. Pateras
- 2nd Department of Pathology, “Attikon” University Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Oskar Franklin
- Department of Surgical and Perioperative Science, Umeå University, Umeå, Sweden
| | | | - Niklas Arnberg
- Department of Clinical Microbiology, Umeå University, Umeå, Sweden
| | - Mitesh Dongre
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.,Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Cedric Patthey
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.,Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Daniel Öhlund
- Wallenberg Centre for Molecular Medicine, Umeå University, Umeå, Sweden.,Department of Radiation Sciences, Umeå University, Umeå, Sweden.,Corresponding Author: Daniel Öhlund, Wallenberg Centre for Molecular Medicine (WCMM), Umeå University, 90187 Umeå, Sweden. Phone: 469-0785-1727; E-mail:
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4
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Analysis of rainbow trout TCRαβ/CD3 complex: An in-silico modeling approach. Mol Immunol 2022; 144:35-43. [DOI: 10.1016/j.molimm.2022.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 11/18/2022]
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5
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Pandey PR, Różycki B, Lipowsky R, Weikl TR. Structural variability and concerted motions of the T cell receptor - CD3 complex. eLife 2021; 10:67195. [PMID: 34490842 PMCID: PMC8504971 DOI: 10.7554/elife.67195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 09/06/2021] [Indexed: 11/28/2022] Open
Abstract
We investigate the structural and orientational variability of the membrane-embedded T cell receptor (TCR) – CD3 complex in extensive atomistic molecular dynamics simulations based on the recent cryo-EM structure determined by Dong et al., 2019. We find that the TCR extracellular (EC) domain is highly variable in its orientation by attaining tilt angles relative to the membrane normal that range from 15° to 55°. The tilt angle of the TCR EC domain is both coupled to a rotation of the domain and to characteristic changes throughout the TCR – CD3 complex, in particular in the EC interactions of the Cβ FG loop of the TCR, as well as in the orientation of transmembrane helices. The concerted motions of the membrane-embedded TCR – CD3 complex revealed in our simulations provide atomistic insights on conformational changes of the complex in response to tilt-inducing forces on antigen-bound TCRs.
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Affiliation(s)
- Prithvi R Pandey
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, Potsdam, Germany
| | - Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Reinhard Lipowsky
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, Potsdam, Germany
| | - Thomas R Weikl
- Max Planck Institute of Colloids and Interfaces, Department of Theory and Bio-Systems, Potsdam, Germany
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6
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Mizsei R, Li X, Chen WN, Szabo M, Wang JH, Wagner G, Reinherz EL, Mallis RJ. A general chemical crosslinking strategy for structural analyses of weakly interacting proteins applied to preTCR-pMHC complexes. J Biol Chem 2021; 296:100255. [PMID: 33837736 PMCID: PMC7948749 DOI: 10.1016/j.jbc.2021.100255] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/29/2020] [Accepted: 01/04/2021] [Indexed: 11/04/2022] Open
Abstract
T lymphocytes discriminate between healthy and infected or cancerous cells via T-cell receptor-mediated recognition of peptides bound and presented by cell-surface-expressed major histocompatibility complex molecules (MHCs). Pre-T-cell receptors (preTCRs) on thymocytes foster development of αβT lymphocytes through their β chain interaction with MHC displaying self-peptides on thymic epithelia. The specific binding of a preTCR with a peptide-MHC complex (pMHC) has been identified previously as forming a weak affinity complex with a distinct interface from that of mature αβTCR. However, a lack of appropriate tools has limited prior efforts to investigate this unique interface. Here we designed a small-scale linkage screening protocol using bismaleimide linkers for determining residue-specific distance constraints between transiently interacting protein pairs in solution. Employing linkage distance restraint-guided molecular modeling, we report the oriented solution docking geometry of a preTCRβ-pMHC interaction. The linkage model of preTCRβ-pMHC complex was independently verified with paramagnetic pseudocontact chemical shift (PCS) NMR of the unlinked protein mixtures. Using linkage screens, we show that the preTCR binds with differing affinities to peptides presented by MHC in solution. Moreover, the C-terminal peptide segment is a key determinant in preTCR-pMHC recognition. We also describe the process for future large-scale production and purification of the linked constructs for NMR, X-ray crystallography, and single-molecule electron microscopy studies.
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MESH Headings
- Antigens, Surface/chemistry
- Antigens, Surface/genetics
- Antigens, Surface/ultrastructure
- Humans
- Major Histocompatibility Complex/genetics
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/ultrastructure
- Nuclear Magnetic Resonance, Biomolecular
- Peptides/chemistry
- Peptides/genetics
- Protein Binding/genetics
- Protein Interaction Domains and Motifs/genetics
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/genetics
- Receptors, Antigen, T-Cell/ultrastructure
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/ultrastructure
- T-Lymphocytes/chemistry
- T-Lymphocytes/immunology
- T-Lymphocytes/ultrastructure
- Thymocytes/chemistry
- Thymocytes/ultrastructure
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Affiliation(s)
- Réka Mizsei
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Biochemistry, Semmelweis University, Budapest, Hungary
| | - Xiaolong Li
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | - Wan-Na Chen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Monika Szabo
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Jia-Huai Wang
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA; Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Ellis L Reinherz
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA.
| | - Robert J Mallis
- Laboratory of Immunobiology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Medical Oncology, Dana Farber Cancer Institute, Boston, Massachusetts, USA; Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA; Department of Dermatology, Harvard Medical School, Boston, Massachusetts, USA.
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7
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Ramesh S, Park S, Call MJ, Im W, Call ME. Experimentally Guided Computational Methods Yield Highly Accurate Insights into Transmembrane Interactions within the T Cell Receptor Complex. J Phys Chem B 2020; 124:10303-10310. [PMID: 33030343 DOI: 10.1021/acs.jpcb.0c06403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Understanding how molecular interactions within the plasma membrane govern assembly, clustering, and conformational changes in single-pass transmembrane (TM) receptors has long presented substantial experimental challenges. Our previous work on activating immune receptors has combined direct biochemical and biophysical characterizations with both independent and experimentally restrained computational methods to provide novel insights into the key TM interactions underpinning assembly and stability of complex, multisubunit receptor systems. The recently published cryo-EM structure of the intact T cell receptor (TCR)-CD3 complex provides a unique opportunity to test the models and predictions arising from these studies, and we find that they are accurate, which we attribute to robust simulation environments and careful consideration of limitations related to studying TM interactions in isolation from additional receptor domains. With this in mind, we revisit results in other immune receptors and look forward to how similar methods may be applied to understand receptors for which little or no structural information is currently available.
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Affiliation(s)
- Samyuktha Ramesh
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Soohyung Park
- Departments of Biological Sciences, Chemistry, Bioengineering, and Computer Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Melissa J Call
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry, Bioengineering, and Computer Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States
| | - Matthew E Call
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia.,Department of Medical Biology, University of Melbourne, Parkville, Victoria 3052, Australia
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8
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Chandler NJ, Call MJ, Call ME. T Cell Activation Machinery: Form and Function in Natural and Engineered Immune Receptors. Int J Mol Sci 2020; 21:E7424. [PMID: 33050044 PMCID: PMC7582382 DOI: 10.3390/ijms21197424] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 12/15/2022] Open
Abstract
The impressive success of chimeric antigen receptor (CAR)-T cell therapies in treating advanced B-cell malignancies has spurred a frenzy of activity aimed at developing CAR-T therapies for other cancers, particularly solid tumors, and optimizing engineered T cells for maximum clinical benefit in many different disease contexts. A rapidly growing body of design work is examining every modular component of traditional single-chain CARs as well as expanding out into many new and innovative engineered immunoreceptor designs that depart from this template. New approaches to immune cell and receptor engineering are being reported with rapidly increasing frequency, and many recent high-quality reviews (including one in this special issue) provide comprehensive coverage of the history and current state of the art in CAR-T and related cellular immunotherapies. In this review, we step back to examine our current understanding of the structure-function relationships in natural and engineered lymphocyte-activating receptors, with an eye towards evaluating how well the current-generation CAR designs recapitulate the most desirable features of their natural counterparts. We identify key areas that we believe are under-studied and therefore represent opportunities to further improve our grasp of form and function in natural and engineered receptors and to rationally design better therapeutics.
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Affiliation(s)
- Nicholas J Chandler
- Structural Biology Division, Walter and Eliza Hall Institute, Parkville, VIC 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Melissa J Call
- Structural Biology Division, Walter and Eliza Hall Institute, Parkville, VIC 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
| | - Matthew E Call
- Structural Biology Division, Walter and Eliza Hall Institute, Parkville, VIC 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC 3052, Australia
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9
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Schamel WW, Alarcon B, Minguet S. The TCR is an allosterically regulated macromolecular machinery changing its conformation while working. Immunol Rev 2020; 291:8-25. [PMID: 31402501 DOI: 10.1111/imr.12788] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 05/30/2019] [Indexed: 12/13/2022]
Abstract
The αβ T-cell receptor (TCR) is a multiprotein complex controlling the activation of T cells. Although the structure of the complete TCR is not known, cumulative evidence supports that the TCR cycles between different conformational states that are promoted either by thermal motion or by force. These structural transitions determine whether the TCR engages intracellular effectors or not, regulating TCR phosphorylation and signaling. As for other membrane receptors, ligand binding selects and stabilizes the TCR in active conformations, and/or switches the TCR to activating states that were not visited before ligand engagement. Here we review the main models of TCR allostery, that is, ligand binding at TCRαβ changes the structure at CD3 and ζ. (a) The ITAM and proline-rich sequence exposure model, in which the TCR's cytoplasmic tails shield each other and ligand binding exposes them for phosphorylation. (b) The membrane-ITAM model, in which the CD3ε and ζ tails are sequestered inside the membrane and again ligand binding exposes them. (c) The mechanosensor model in which ligand binding exerts force on the TCR, inducing structural changes that allow signaling. Since these models are complementary rather than competing, we propose a unified model that aims to incorporate all existing data.
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Affiliation(s)
- Wolfgang W Schamel
- Department of Immunology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Center of Chronic Immunodeficiency CCI, University Clinics and Medical Faculty, Freiburg, Germany
| | - Balbino Alarcon
- Centro de Biología Molecular Severo Ochoa, CSIC-UAM, Madrid, Spain
| | - Susana Minguet
- Department of Immunology, Faculty of Biology, Albert-Ludwigs-University of Freiburg, Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.,Center of Chronic Immunodeficiency CCI, University Clinics and Medical Faculty, Freiburg, Germany
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10
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Xu X, Li H, Xu C. Structural understanding of T cell receptor triggering. Cell Mol Immunol 2020; 17:193-202. [PMID: 32047259 DOI: 10.1038/s41423-020-0367-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 01/08/2020] [Indexed: 11/09/2022] Open
Abstract
The T cell receptor (TCR) is one of the most complicated receptors in mammalian cells, and its triggering mechanism remains mysterious. As an octamer complex, TCR comprises an antigen-binding subunit (TCRαβ) and three CD3 signaling subunits (CD3ζζ, CD3δε, and CD3γε). Engagement of TCRαβ with an antigen peptide presented on the MHC leads to tyrosine phosphorylation of the immunoreceptor tyrosine-based activation motif (ITAM) in CD3 cytoplasmic domains (CDs), thus translating extracellular binding kinetics to intracellular signaling events. Whether conformational change plays an important role in the transmembrane signal transduction of TCR is under debate. Attracted by the complexity and functional importance of TCR, many groups have been studying TCR structure and triggering for decades using diverse biochemical and biophysical tools. Here, we synthesize these structural studies and discuss the relevance of the conformational change model in TCR triggering.
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Affiliation(s)
- Xinyi Xu
- State Key Laboratory of Molecular Biology, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, 320 Yueyang Road, 200031, Shanghai, China
| | - Hua Li
- State Key Laboratory of Molecular Biology, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, 320 Yueyang Road, 200031, Shanghai, China
| | - Chenqi Xu
- State Key Laboratory of Molecular Biology, Shanghai Science Research Center, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences; University of Chinese Academy of Sciences, 320 Yueyang Road, 200031, Shanghai, China. .,School of Life Science and Technology, ShanghaiTech University, 100 Haike Road, 201210, Shanghai, China.
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11
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Mariuzza RA, Agnihotri P, Orban J. The structural basis of T-cell receptor (TCR) activation: An enduring enigma. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49904-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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12
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Ultrasmall silica nanoparticles directly ligate the T cell receptor complex. Proc Natl Acad Sci U S A 2019; 117:285-291. [PMID: 31871161 DOI: 10.1073/pnas.1911360117] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The impact of ultrasmall nanoparticles (<10-nm diameter) on the immune system is poorly understood. Recently, ultrasmall silica nanoparticles (USSN), which have gained increasing attention for therapeutic applications, were shown to stimulate T lymphocytes directly and at relatively low-exposure doses. Delineating underlying mechanisms and associated cell signaling will hasten therapeutic translation and is reported herein. Using competitive binding assays and molecular modeling, we established that the T cell receptor (TCR):CD3 complex is required for USSN-induced T cell activation, and that direct receptor complex-particle interactions are permitted both sterically and electrostatically. Activation is not limited to αβ TCR-bearing T cells since those with γδ TCR showed similar responses, implying that USSN mediate their effect by binding to extracellular domains of the flanking CD3 regions of the TCR complex. We confirmed that USSN initiated the signaling pathway immediately downstream of the TCR with rapid phosphorylation of both ζ-chain-associated protein 70 and linker for activation of T cells protein. However, T cell proliferation or IL-2 secretion were only triggered by USSN when costimulatory anti-CD28 or phorbate esters were present, demonstrating that the specific impact of USSN is in initiation of the primary, nuclear factor of activated T cells-pathway signaling from the TCR complex. Hence, we have established that USSN are partial agonists for the TCR complex because of induction of the primary T cell activation signal. Their ability to bind the TCR complex rapidly, and then to dissolve into benign orthosilicic acid, makes them an appealing option for therapies targeted at transient TCR:CD3 receptor binding.
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13
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Mariuzza RA, Agnihotri P, Orban J. The structural basis of T-cell receptor (TCR) activation: An enduring enigma. J Biol Chem 2019; 295:914-925. [PMID: 31848223 DOI: 10.1074/jbc.rev119.009411] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
T cells are critical for protective immune responses to pathogens and tumors. The T-cell receptor (TCR)-CD3 complex is composed of a diverse αβ TCR heterodimer noncovalently associated with the invariant CD3 dimers CD3ϵγ, CD3ϵδ, and CD3ζζ. The TCR mediates recognition of antigenic peptides bound to MHC molecules (pMHC), whereas the CD3 molecules transduce activation signals to the T cell. Whereas much is known about downstream T-cell signaling pathways, the mechanism whereby TCR engagement by pMHC is first communicated to the CD3 signaling apparatus, a process termed early T-cell activation, remains largely a mystery. In this review, we examine the molecular basis for TCR activation in light of the recently determined cryoEM structure of a complete TCR-CD3 complex. This structure provides an unprecedented opportunity to assess various signaling models that have been proposed for the TCR. We review evidence from single-molecule and structural studies for force-induced conformational changes in the TCR-CD3 complex, for dynamically-driven TCR allostery, and for pMHC-induced structural changes in the transmembrane and cytoplasmic regions of CD3 subunits. We identify major knowledge gaps that must be filled in order to arrive at a comprehensive model of TCR activation that explains, at the molecular level, how pMHC-specific information is transmitted across the T-cell membrane to initiate intracellular signaling. An in-depth understanding of this process will accelerate the rational design of immunotherapeutic agents targeting the TCR-CD3 complex.
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Affiliation(s)
- Roy A Mariuzza
- W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850 .,Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Pragati Agnihotri
- W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850.,Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - John Orban
- W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850 .,Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742
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14
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Connolly A, Gagnon E. Electrostatic interactions: From immune receptor assembly to signaling. Immunol Rev 2019; 291:26-43. [DOI: 10.1111/imr.12769] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 04/30/2019] [Indexed: 12/21/2022]
Affiliation(s)
- Audrey Connolly
- Institut de Recherche en Immunologie et Cancérologie/Institute for Research in Immunology and Cancer Montréal Québec Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine Université de Montréal Montréal Québec Canada
| | - Etienne Gagnon
- Institut de Recherche en Immunologie et Cancérologie/Institute for Research in Immunology and Cancer Montréal Québec Canada
- Département de Microbiologie, Infectiologie et Immunologie, Faculté de Médecine Université de Montréal Montréal Québec Canada
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15
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Mallis RJ, Brazin KN, Duke-Cohan JS, Hwang W, Wang JH, Wagner G, Arthanari H, Lang MJ, Reinherz EL. NMR: an essential structural tool for integrative studies of T cell development, pMHC ligand recognition and TCR mechanobiology. JOURNAL OF BIOMOLECULAR NMR 2019; 73:319-332. [PMID: 30815789 PMCID: PMC6693947 DOI: 10.1007/s10858-019-00234-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 02/06/2019] [Indexed: 05/05/2023]
Abstract
Early studies of T cell structural biology using X-ray crystallography, surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) focused on a picture of the αβT cell receptor (αβTCR) component domains and their cognate ligands (peptides bound to MHC molecules, i.e. pMHCs) as static interaction partners. Moving forward requires integrating this corpus of data with dynamic technologies such as NMR, molecular dynamics (MD) simulations and real-time single molecule (SM) studies exemplified by optical tweezers (OT). NMR bridges relevant timescales and provides the potential for an all-atom dynamic description of αβTCR components prior to and during interactions with binding partners. SM techniques have opened up vistas in understanding the non-equilibrium nature of T cell signaling through the introduction of force-mediated binding measurements into the paradigm for T cell function. In this regard, bioforces consequent to T-lineage cell motility are now perceived as placing piconewton (pN)-level loads on single receptor-pMHC bonds to impact structural change and αβT-lineage biology, including peptide discrimination, cellular activation, and developmental progression. We discuss herein essential NMR technologies in illuminating the role of ligand binding in the preT cell receptor (preTCR), the αβTCR developmental precursor, and convergence of NMR, SM and MD data in advancing our comprehension of T cell development. More broadly we review the central hypothesis that the αβTCR is a mechanosensor, fostered by breakthrough NMR-based structural insights. Collectively, elucidating dynamic aspects through the integrative use of NMR, SM, and MD shall advance fundamental appreciation of the mechanism of T cell signaling as well as inform translational efforts in αβTCR and chimeric T cell (CAR-T) immunotherapies and T cell vaccinology.
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Affiliation(s)
- Robert J Mallis
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Department of Dermatology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
| | - Kristine N Brazin
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Jonathan S Duke-Cohan
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, 77843, USA
- Department of Materials Science & Engineering, Texas A&M University, College Station, TX, 77843, USA
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, 02455, Republic of Korea
| | - Jia-Huai Wang
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, 02115, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Haribabu Arthanari
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
| | - Matthew J Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, 37235, USA.
| | - Ellis L Reinherz
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, 02115, USA.
- Department of Medicine, Harvard Medical School, Boston, MA, 02115, USA.
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16
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Buckle AM, Borg NA. Integrating Experiment and Theory to Understand TCR-pMHC Dynamics. Front Immunol 2018; 9:2898. [PMID: 30581442 PMCID: PMC6293202 DOI: 10.3389/fimmu.2018.02898] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/26/2018] [Indexed: 11/13/2022] Open
Abstract
The conformational dynamism of proteins is well established. Rather than having a single structure, proteins are more accurately described as a conformational ensemble that exists across a rugged energy landscape, where different conformational sub-states interconvert. The interaction between αβ T cell receptors (TCR) and cognate peptide-MHC (pMHC) is no exception, and is a dynamic process that involves substantial conformational change. This review focuses on technological advances that have begun to establish the role of conformational dynamics and dynamic allostery in TCR recognition of the pMHC and the early stages of signaling. We discuss how the marriage of molecular dynamics (MD) simulations with experimental techniques provides us with new ways to dissect and interpret the process of TCR ligation. Notably, application of simulation techniques lags behind other fields, but is predicted to make substantial contributions. Finally, we highlight integrated approaches that are being used to shed light on some of the key outstanding questions in the early events leading to TCR signaling.
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Affiliation(s)
- Ashley M Buckle
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
| | - Natalie A Borg
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC, Australia
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17
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The T Cell Antigen Receptor α Transmembrane Domain Coordinates Triggering through Regulation of Bilayer Immersion and CD3 Subunit Associations. Immunity 2018; 49:829-841.e6. [PMID: 30389415 DOI: 10.1016/j.immuni.2018.09.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/15/2018] [Accepted: 09/07/2018] [Indexed: 12/18/2022]
Abstract
Initial molecular details of cellular activation following αβT cell antigen receptor (TCR) ligation by peptide-major histocompatibility complexes (pMHC) remain unexplored. We determined the nuclear magnetic resonance (NMR) structure of the TCRα subunit transmembrane (TM) domain revealing a bipartite helix whose segmentation fosters dynamic movement. Positively charged TM residues Arg251 and Lys256 project from opposite faces of the helix, with Lys256 controlling immersion depth. Their modification caused stepwise reduction in TCR associations with CD3ζζ homodimers and CD3εγ plus CD3εδ heterodimers, respectively, leading to an activated transcriptome. Optical tweezers revealed that Arg251 and Lys256 mutations altered αβTCR-pMHC bond lifetimes, while mutations within interacting TCRα connecting peptide and CD3δ CxxC motif juxtamembrane elements selectively attenuated signal transduction. Our findings suggest that mechanical forces applied during pMHC ligation initiate T cell activation via a dissociative mechanism, shifting disposition of those basic sidechains to rearrange TCR complex membrane topology and weaken TCRαβ and CD3 associations.
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18
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19
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Abstract
T cell receptors (TCRs) are protein complexes formed by six different polypeptides. In most T cells, TCRs are composed of αβ subunits displaying immunoglobulin-like variable domains that recognize peptide antigens associated with major histocompatibility complex molecules expressed on the surface of antigen-presenting cells. TCRαβ subunits are associated with the CD3 complex formed by the γ, δ, ε, and ζ subunits, which are invariable and ensure signal transduction. Here, we review how the expression and function of TCR complexes are orchestrated by several fine-tuned cellular processes that encompass (a) synthesis of the subunits and their correct assembly and expression at the plasma membrane as a single functional complex, (b) TCR membrane localization and dynamics at the plasma membrane and in endosomal compartments, (c) TCR signal transduction leading to T cell activation, and (d) TCR degradation. These processes balance each other to ensure efficient T cell responses to a variety of antigenic stimuli while preventing autoimmunity.
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Affiliation(s)
- Andrés Alcover
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France; ,
| | - Balbino Alarcón
- Severo Ochoa Center for Molecular Biology, CSIC-UAM, Madrid 28049, Spain;
| | - Vincenzo Di Bartolo
- Lymphocyte Cell Biology Unit, INSERM U1221, Department of Immunology, Institut Pasteur, Paris 75015, France; ,
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20
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Zimmermann K, Eells R, Heinrich F, Rintoul S, Josey B, Shekhar P, Lösche M, Stern LJ. The cytosolic domain of T-cell receptor ζ associates with membranes in a dynamic equilibrium and deeply penetrates the bilayer. J Biol Chem 2017; 292:17746-17759. [PMID: 28893902 PMCID: PMC5663876 DOI: 10.1074/jbc.m117.794370] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/21/2017] [Indexed: 11/06/2022] Open
Abstract
Interactions between lipid bilayers and the membrane-proximal regions of membrane-associated proteins play important roles in regulating membrane protein structure and function. The T-cell antigen receptor is an assembly of eight single-pass membrane-spanning subunits on the surface of T lymphocytes that initiates cytosolic signaling cascades upon binding antigens presented by MHC-family proteins on antigen-presenting cells. Its ζ-subunit contains multiple cytosolic immunoreceptor tyrosine-based activation motifs involved in signal transduction, and this subunit by itself is sufficient to couple extracellular stimuli to intracellular signaling events. Interactions of the cytosolic domain of ζ (ζcyt) with acidic lipids have been implicated in the initiation and regulation of transmembrane signaling. ζcyt is unstructured in solution. Interaction with acidic phospholipids induces structure, but its disposition when bound to lipid bilayers is controversial. Here, using surface plasmon resonance and neutron reflection, we characterized the interaction of ζcyt with planar lipid bilayers containing mixtures of acidic and neutral lipids. We observed two binding modes of ζcyt to the bilayers in dynamic equilibrium: one in which ζcyt is peripherally associated with lipid headgroups and one in which it penetrates deeply into the bilayer. Such an equilibrium between the peripherally bound and embedded forms of ζcyt apparently controls accessibility of the immunoreceptor tyrosine-based activation signal transduction pathway. Our results reconcile conflicting findings of the ζ structure reported in previous studies and provide a framework for understanding how lipid interactions regulate motifs to tyrosine kinases and may regulate the T-cell antigen receptor biological activities for this cell-surface receptor system.
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Affiliation(s)
| | | | - Frank Heinrich
- the Departments of Physics and
- the National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, Maryland 20899
| | | | | | | | - Mathias Lösche
- the Departments of Physics and
- the National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, Maryland 20899
- Biomedical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, and
| | - Lawrence J Stern
- From the Departments of Pathology and
- Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01655
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21
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Merkle PS, Irving M, Hongjian S, Ferber M, Jørgensen TJD, Scholten K, Luescher I, Coukos G, Zoete V, Cuendet MA, Michielin O, Rand KD. The T-Cell Receptor Can Bind to the Peptide-Bound Major Histocompatibility Complex and Uncomplexed β2-Microglobulin through Distinct Binding Sites. Biochemistry 2017; 56:3945-3961. [DOI: 10.1021/acs.biochem.7b00385] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Patrick S. Merkle
- Department
of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Melita Irving
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - Song Hongjian
- Department
of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Mathias Ferber
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
| | - Thomas J. D. Jørgensen
- Department
of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark
| | - Kirsten Scholten
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - Immanuel Luescher
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - George Coukos
- Ludwig
Branch for Cancer Research, University of Lausanne, 1015 Lausanne, Switzerland
| | - Vincent Zoete
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
| | - Michel A. Cuendet
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
- Department
of Physiology and Biophysics, Weill Cornell Medical College, 1300
York Avenue, New York, New
York 10065, United States
| | - Olivier Michielin
- Swiss Institute of Bioinformatics, Bâtiment Génopode, UNIL Sorge, 1015 Lausanne, Switzerland
| | - Kasper D. Rand
- Department
of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark
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22
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Natarajan K, McShan AC, Jiang J, Kumirov VK, Wang R, Zhao H, Schuck P, Tilahun ME, Boyd LF, Ying J, Bax A, Margulies DH, Sgourakis NG. An allosteric site in the T-cell receptor Cβ domain plays a critical signalling role. Nat Commun 2017; 8:15260. [PMID: 28508865 PMCID: PMC5440810 DOI: 10.1038/ncomms15260] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 03/14/2017] [Indexed: 12/21/2022] Open
Abstract
The molecular mechanism through which the interaction of a clonotypic αβ T-cell receptor (TCR) with a peptide-loaded major histocompatibility complex (p/MHC) leads to T-cell activation is not yet fully understood. Here we exploit a high-affinity TCR (B4.2.3) to examine the structural changes that accompany binding to its p/MHC ligand (P18-I10/H2-Dd). In addition to conformational changes in complementarity-determining regions (CDRs) of the TCR seen in comparison of unliganded and bound X-ray structures, NMR characterization of the TCR β-chain dynamics reveals significant chemical shift effects in sites removed from the MHC-binding site. Remodelling of electrostatic interactions near the Cβ H3 helix at the membrane-proximal face of the TCR, a region implicated in interactions with the CD3 co-receptor, suggests a possible role for an allosteric mechanism in TCR signalling. The contribution of these TCR residues to signal transduction is supported by mutagenesis and T-cell functional assays.
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MESH Headings
- Allosteric Site/immunology
- Animals
- Complementarity Determining Regions/chemistry
- Complementarity Determining Regions/metabolism
- Crystallography, X-Ray
- Major Histocompatibility Complex/immunology
- Mice
- Molecular Dynamics Simulation
- Mutagenesis
- Peptides/metabolism
- Protein Binding/immunology
- Protein Domains/immunology
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Signal Transduction/immunology
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
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Affiliation(s)
- Kannan Natarajan
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Andrew C. McShan
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Vlad K Kumirov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
| | - Rui Wang
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Huaying Zhao
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Peter Schuck
- Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Mulualem E. Tilahun
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Lisa F. Boyd
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - David H. Margulies
- Molecular Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nikolaos G. Sgourakis
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, USA
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23
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Kashima D, Kawade R, Nagamune T, Kawahara M. A Chemically Inducible Helper Module for Detecting Protein–Protein Interactions with Tunable Sensitivity Based on KIPPIS. Anal Chem 2017; 89:4824-4830. [DOI: 10.1021/acs.analchem.6b04063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Daiki Kashima
- Department of Chemistry and
Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Raiji Kawade
- Department of Chemistry and
Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Teruyuki Nagamune
- Department of Chemistry and
Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
| | - Masahiro Kawahara
- Department of Chemistry and
Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
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24
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Abstract
Triggering of cell-mediated immunity is largely dependent on the recognition of foreign or abnormal molecules by a myriad of cell surface-bound receptors. Many activating immune receptors do not possess any intrinsic signaling capacity but instead form noncovalent complexes with one or more dimeric signaling modules that communicate with a common set of kinases to initiate intracellular information-transfer pathways. This modular architecture, where the ligand binding and signaling functions are detached from one another, is a common theme that is widely employed throughout the innate and adaptive arms of immune systems. The evolutionary advantages of this highly adaptable platform for molecular recognition are visible in the variety of ligand-receptor interactions that can be linked to common signaling pathways, the diversification of receptor modules in response to pathogen challenges, and the amplification of cellular responses through incorporation of multiple signaling motifs. Here we provide an overview of the major classes of modular activating immune receptors and outline the current state of knowledge regarding how these receptors assemble, recognize their ligands, and ultimately trigger intracellular signal transduction pathways that activate immune cell effector functions.
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Affiliation(s)
- Richard Berry
- Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University , Clayton, Victoria 3800, Australia.,ARC Centre of Excellence in Advanced Molecular Imaging, Monash University , Clayton, Victoria 3800, Australia
| | - Matthew E Call
- Structural Biology Division, The Walter and Eliza Hall Institute of Medical Research , Parkville, Victoria 3052, Australia.,Department of Medical Biology, University of Melbourne , Parkville, Victoria 3052, Australia
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25
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A conserved αβ transmembrane interface forms the core of a compact T-cell receptor-CD3 structure within the membrane. Proc Natl Acad Sci U S A 2016; 113:E6649-E6658. [PMID: 27791034 DOI: 10.1073/pnas.1611445113] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The T-cell antigen receptor (TCR) is an assembly of eight type I single-pass membrane proteins that occupies a central position in adaptive immunity. Many TCR-triggering models invoke an alteration in receptor complex structure as the initiating event, but both the precise subunit organization and the pathway by which ligand-induced alterations are transferred to the cytoplasmic signaling domains are unknown. Here, we show that the receptor complex transmembrane (TM) domains form an intimately associated eight-helix bundle organized by a specific interhelical TCR TM interface. The salient features of this core structure are absolutely conserved between αβ and γδ TCR sequences and throughout vertebrate evolution, and mutations at key interface residues caused defects in the formation of stable TCRαβ:CD3δε:CD3γε:ζζ complexes. These findings demonstrate that the eight TCR-CD3 subunits form a compact and precisely organized structure within the membrane and provide a structural basis for further investigation of conformationally regulated models of transbilayer TCR signaling.
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26
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Glassman CR, Parrish HL, Deshpande NR, Kuhns MS. The CD4 and CD3δε Cytosolic Juxtamembrane Regions Are Proximal within a Compact TCR-CD3-pMHC-CD4 Macrocomplex. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2016; 196:4713-22. [PMID: 27183595 PMCID: PMC4875830 DOI: 10.4049/jimmunol.1502110] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 03/29/2016] [Indexed: 12/15/2022]
Abstract
TCRs relay information about peptides embedded within MHC molecules (pMHC) to the ITAMs of the associated CD3γε, CD3δε, and CD3ζζ signaling modules. CD4 then recruits the Src kinase p56(Lck) (Lck) to the TCR-CD3 complex to phosphorylate the ITAMs, initiate intracellular signaling, and drive CD4(+) T cell fate decisions. Whereas the six ITAMs of CD3ζζ are key determinants of T cell development, activation, and the execution of effector functions, multiple models predict that CD4 recruits Lck proximal to the four ITAMs of the CD3 heterodimers. We tested these models by placing FRET probes at the cytosolic juxtamembrane regions of CD4 and the CD3 subunits to evaluate their relationship upon pMHC engagement in mouse cell lines. The data are consistent with a compact assembly in which CD4 is proximal to CD3δε, CD3ζζ resides behind the TCR, and CD3γε is offset from CD3δε. These results advance our understanding of the architecture of the TCR-CD3-pMHC-CD4 macrocomplex and point to regions of high CD4-Lck + ITAM concentrations therein. The findings thus have implications for TCR signaling, as phosphorylation of the CD3 ITAMs by CD4-associated Lck is important for CD4(+) T cell fate decisions.
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Affiliation(s)
- Caleb R Glassman
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724
| | - Heather L Parrish
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724
| | - Neha R Deshpande
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724; The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, AZ 85724; and
| | - Michael S Kuhns
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724; The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, AZ 85724; and The BIO5 Institute, The University of Arizona College of Medicine, Tucson, AZ 85724
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27
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Natarajan A, Nadarajah V, Felsovalyi K, Wang W, Jeyachandran VR, Wasson RA, Cardozo T, Bracken C, Krogsgaard M. Structural Model of the Extracellular Assembly of the TCR-CD3 Complex. Cell Rep 2016; 14:2833-45. [PMID: 26997265 DOI: 10.1016/j.celrep.2016.02.081] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 12/24/2015] [Accepted: 02/21/2016] [Indexed: 11/29/2022] Open
Abstract
Antigen recognition of peptide-major histocompatibility complexes (pMHCs) by T cells, a key step in initiating adaptive immune responses, is performed by the T cell receptor (TCR) bound to CD3 heterodimers. However, the biophysical basis of the transmission of TCR-CD3 extracellular interaction into a productive intracellular signaling sequence remains incomplete. Here we used nuclear magnetic resonance (NMR) spectroscopy combined with mutational analysis and computational docking to derive a structural model of the extracellular TCR-CD3 assembly. In the inactivated state, CD3γε interacts with the helix 3 and helix 4-F strand regions of the TCR Cβ subunit, whereas CD3δε interacts with the F and C strand regions of the TCR Cα subunit in this model, placing the CD3 subunits on opposing sides of the TCR. This work identifies the molecular contacts between the TCR and CD3 subunits, identifying a physical basis for transmitting an activating signal through the complex.
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Affiliation(s)
- Aswin Natarajan
- Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Vidushan Nadarajah
- Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Klara Felsovalyi
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Wenjuan Wang
- Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Vivian R Jeyachandran
- Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Riley A Wasson
- Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - Clay Bracken
- Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA
| | - Michelle Krogsgaard
- Laura and Isaac Perlmutter Cancer Center, New York University School of Medicine, New York, NY 10016, USA; Interdiciplinary Cooperative Melanoma Group, New York University School of Medicine, New York, NY 10016, USA; Department of Pathology, New York University School of Medicine, New York, NY 10016, USA.
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28
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Reinherz EL. αβ TCR-mediated recognition: relevance to tumor-antigen discovery and cancer immunotherapy. Cancer Immunol Res 2016; 3:305-12. [PMID: 25847967 DOI: 10.1158/2326-6066.cir-15-0042] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
αβ T lymphocytes sense perturbations in host cellular body components induced by infectious pathogens, oncogenic transformation, or chemical or physical damage. Millions to billions of these lymphocytes are generated through T-lineage development in the thymus, each endowed with a clonally restricted surface T-cell receptor (TCR). An individual TCR has the capacity to recognize a distinct "foreign" peptide among the myriad of antigens that the mammalian host must be capable of detecting. TCRs explicitly distinguish foreign from self-peptides bound to major histocompatibility complex (MHC) molecules. This is a daunting challenge, given that the MHC-linked peptidome consists of thousands of distinct peptides with a relevant nonself target antigen often embedded at low number, among orders of magnitude higher frequency self-peptides. In this Masters of Immunology article, I review how TCR structure and attendant mechanobiology involving nonlinear responses affect sensitivity as well as specificity to meet this requirement. Assessment of human tumor-cell display using state-of-the-art mass spectrometry physical detection methods that quantify epitope copy number can help to provide information about requisite T-cell functional avidity affording protection and/or therapeutic immunity. Future rational CD8 cytotoxic T-cell-based vaccines may follow, targeting virally induced cancers, other nonviral immunogenic tumors, and potentially even nonimmunogenic tumors whose peptide display can be purposely altered by MHC-binding drugs to stimulate immune attack.
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Affiliation(s)
- Ellis L Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts. Department of Medicine, Harvard Medical School, Boston, Massachusetts.
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29
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Brazin KN, Mallis RJ, Das DK, Feng Y, Hwang W, Wang JH, Wagner G, Lang MJ, Reinherz EL. Structural Features of the αβTCR Mechanotransduction Apparatus That Promote pMHC Discrimination. Front Immunol 2015; 6:441. [PMID: 26388869 PMCID: PMC4558533 DOI: 10.3389/fimmu.2015.00441] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 08/14/2015] [Indexed: 12/20/2022] Open
Abstract
The αβTCR was recently revealed to function as a mechanoreceptor. That is, it leverages mechanical energy generated during immune surveillance and at the immunological synapse to drive biochemical signaling following ligation by a specific foreign peptide-MHC complex (pMHC). Here, we review the structural features that optimize this transmembrane (TM) receptor for mechanotransduction. Specialized adaptations include (1) the CβFG loop region positioned between Vβ and Cβ domains that allosterically gates both dynamic T cell receptor (TCR)-pMHC bond formation and lifetime; (2) the rigid super β-sheet amalgams of heterodimeric CD3εγ and CD3εδ ectodomain components of the αβTCR complex; (3) the αβTCR subunit connecting peptides linking the extracellular and TM segments, particularly the oxidized CxxC motif in each CD3 heterodimeric subunit that facilitates force transfer through the TM segments and surrounding lipid, impacting cytoplasmic tail conformation; and (4) quaternary changes in the αβTCR complex that accompany pMHC ligation under load. How bioforces foster specific αβTCR-based pMHC discrimination and why dynamic bond formation is a primary basis for kinetic proofreading are discussed. We suggest that the details of the molecular rearrangements of individual αβTCR subunit components can be analyzed utilizing a combination of structural biology, single-molecule FRET, optical tweezers, and nanobiology, guided by insightful atomistic molecular dynamic studies. Finally, we review very recent data showing that the pre-TCR complex employs a similar mechanobiology to that of the αβTCR to interact with self-pMHC ligands, impacting early thymic repertoire selection prior to the CD4(+)CD8(+) double positive thymocyte stage of development.
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Affiliation(s)
- Kristine N. Brazin
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Robert J. Mallis
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Dibyendu Kumar Das
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Yinnian Feng
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
| | - Wonmuk Hwang
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- Department of Materials Science and Engineering, Texas A&M University, College Station, TX, USA
- School of Computational Sciences, Korea Institute for Advanced Study, Seoul, South Korea
| | - Jia-huai Wang
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Matthew J. Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA
| | - Ellis L. Reinherz
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
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30
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Lee MS, Glassman CR, Deshpande NR, Badgandi HB, Parrish HL, Uttamapinant C, Stawski PS, Ting AY, Kuhns MS. A Mechanical Switch Couples T Cell Receptor Triggering to the Cytoplasmic Juxtamembrane Regions of CD3ζζ. Immunity 2015; 43:227-39. [PMID: 26231119 PMCID: PMC4545397 DOI: 10.1016/j.immuni.2015.06.018] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 04/30/2015] [Accepted: 06/23/2015] [Indexed: 10/23/2022]
Abstract
The eight-subunit T cell receptor (TCR)-CD3 complex is the primary determinant for T cell fate decisions. Yet how it relays ligand-specific information across the cell membrane for conversion to chemical signals remains unresolved. We hypothesized that TCR engagement triggers a change in the spatial relationship between the associated CD3ζζ subunits at the junction where they emerge from the membrane into the cytoplasm. Using three in situ proximity assays based on ID-PRIME, FRET, and EPOR activity, we determined that the cytosolic juxtamembrane regions of the CD3ζζ subunits are spread apart upon assembly into the TCR-CD3 complex. TCR engagement then triggered their apposition. This mechanical switch resides upstream of the CD3ζζ intracellular motifs that initiate chemical signaling, as well as the polybasic stretches that regulate signal potentiation. These findings provide a framework from which to examine triggering events for activating immune receptors and other complex molecular machines.
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Affiliation(s)
- Mark S Lee
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Caleb R Glassman
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Neha R Deshpande
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724, USA; The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Hemant B Badgandi
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Heather L Parrish
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724, USA
| | - Chayasith Uttamapinant
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02138, USA
| | - Philipp S Stawski
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02138, USA
| | - Alice Y Ting
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02138, USA
| | - Michael S Kuhns
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, AZ 85724, USA; The Arizona Center on Aging, The University of Arizona College of Medicine, Tucson, AZ 85724, USA; The BIO-5 Institute, The University of Arizona College of Medicine, Tucson, AZ 85724, USA.
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31
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He Y, Rangarajan S, Kerzic M, Luo M, Chen Y, Wang Q, Yin Y, Workman CJ, Vignali KM, Vignali DAA, Mariuzza RA, Orban J. Identification of the Docking Site for CD3 on the T Cell Receptor β Chain by Solution NMR. J Biol Chem 2015; 290:19796-805. [PMID: 26109064 DOI: 10.1074/jbc.m115.663799] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 12/23/2022] Open
Abstract
The T cell receptor (TCR)-CD3 complex is composed of a genetically diverse αβ TCR heterodimer associated noncovalently with the invariant CD3 dimers CD3ϵγ, CD3ϵδ, and CD3ζζ. The TCR mediates peptide-MHC recognition, whereas the CD3 molecules transduce activation signals to the T cell. Although much is known about downstream T cell signaling pathways, the mechanism whereby TCR engagement by peptide-MHC initiates signaling is poorly understood. A key to solving this problem is defining the spatial organization of the TCR-CD3 complex and the interactions between its subunits. We have applied solution NMR methods to identify the docking site for CD3 on the β chain of a human autoimmune TCR. We demonstrate a low affinity but highly specific interaction between the extracellular domains of CD3 and the TCR constant β (Cβ) domain that requires both CD3ϵγ and CD3ϵδ subunits. The mainly hydrophilic docking site, comprising 9-11 solvent-accessible Cβ residues, is relatively small (∼400 Å(2)), consistent with the weak interaction between TCR and CD3 extracellular domains, and devoid of glycosylation sites. The docking site is centered on the αA and αB helices of Cβ, which are located at the base of the TCR. This positions CD3ϵγ and CD3ϵδ between the TCR and the T cell membrane, permitting us to distinguish among several possible models of TCR-CD3 association. We further correlate structural results from NMR with mutational data on TCR-CD3 interactions from cell-based assays.
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Affiliation(s)
- Yanan He
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, the Departments of Chemistry and Biochemistry and
| | - Sneha Rangarajan
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742
| | - Melissa Kerzic
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Ming Luo
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China, and
| | - Yihong Chen
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Qian Wang
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Yiyuan Yin
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Creg J Workman
- the Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Kate M Vignali
- the Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Dario A A Vignali
- the Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261
| | - Roy A Mariuzza
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742,
| | - John Orban
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, the Departments of Chemistry and Biochemistry and
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32
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Pre-TCR ligand binding impacts thymocyte development before αβTCR expression. Proc Natl Acad Sci U S A 2015; 112:8373-8. [PMID: 26056289 DOI: 10.1073/pnas.1504971112] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Adaptive cellular immunity requires accurate self- vs. nonself-discrimination to protect against infections and tumorous transformations while at the same time excluding autoimmunity. This vital capability is programmed in the thymus through selection of αβT-cell receptors (αβTCRs) recognizing peptides bound to MHC molecules (pMHC). Here, we show that the pre-TCR (preTCR), a pTα-β heterodimer appearing before αβTCR expression, directs a previously unappreciated initial phase of repertoire selection. Contrasting with the ligand-independent model of preTCR function, we reveal through NMR and bioforce-probe analyses that the β-subunit binds pMHC using Vβ complementarity-determining regions as well as an exposed hydrophobic Vβ patch characteristic of the preTCR. Force-regulated single bonds akin to those of αβTCRs but with more promiscuous ligand specificity trigger calcium flux. Thus, thymic development involves sequential β- and then, αβ-repertoire tuning, whereby preTCR interactions with self pMHC modulate early thymocyte expansion, with implications for β-selection, immunodominant peptide recognition, and germ line-encoded MHC interaction.
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33
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Reinherz EL, Wang JH. Codification of bidentate pMHC interaction with TCR and its co-receptor. Trends Immunol 2015; 36:300-6. [PMID: 25818864 PMCID: PMC4420642 DOI: 10.1016/j.it.2015.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 02/03/2023]
Abstract
A 1983 Immunology Today rostrum hypothesized that each T cell has two recognition units: a T cell receptor (TCR) complex, which binds antigen associated with a polymorphic region of a MHC molecule (pMHC), and a CD4 or CD8 molecule that binds to a conserved region of that same MHC gene product (class II or I, respectively). Structural biology has since precisely revealed those bidentate pMHC interactions. TCRαβ ligates the membrane-distal antigen-binding MHC platform, whereas CD8 clamps a membrane-proximal MHCI α3 domain loop and CD4 docks to a hydrophobic crevice between MHCII α2 and β2 domains. Here, we review how MHC class-restricted binding impacts signaling and lineage commitment, discussing TCR force-driven conformational transitions that may optimally expose the co-receptor docking site on MHC.
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Affiliation(s)
- Ellis L Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
| | - Jia-huai Wang
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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34
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Perica K, Kosmides AK, Schneck JP. Linking form to function: Biophysical aspects of artificial antigen presenting cell design. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1853:781-90. [PMID: 25200637 PMCID: PMC4344884 DOI: 10.1016/j.bbamcr.2014.09.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 08/15/2014] [Accepted: 09/01/2014] [Indexed: 12/22/2022]
Abstract
Artificial antigen presenting cells (aAPCs) are engineered platforms for T cell activation and expansion, synthesized by coupling T cell activating proteins to the surface of cell lines or biocompatible particles. They can serve both as model systems to study the basic aspects of T cell signaling and translationally as novel approaches for either active or adoptive immunotherapy. Historically, these reductionist systems have not been designed to mimic the temporally and spatially complex interactions observed during endogenous T cell-APC contact, which include receptor organization at both micro- and nanoscales and dynamic changes in cell and membrane morphologies. Here, we review how particle size and shape, as well as heterogenous distribution of T cell activating proteins on the particle surface, are critical aspects of aAPC design. In doing so, we demonstrate how insights derived from endogenous T cell activation can be applied to optimize aAPC, and in turn how aAPC platforms can be used to better understand endogenous T cell stimulation. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling.
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Affiliation(s)
- Karlo Perica
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Institute of Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Alyssa K Kosmides
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Institute of Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Jonathan P Schneck
- Institute of Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Pathology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Oncology, Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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35
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Force-dependent transition in the T-cell receptor β-subunit allosterically regulates peptide discrimination and pMHC bond lifetime. Proc Natl Acad Sci U S A 2015; 112:1517-22. [PMID: 25605925 DOI: 10.1073/pnas.1424829112] [Citation(s) in RCA: 181] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The αβ T-cell receptor (TCR) on each T lymphocyte mediates exquisite specificity for a particular foreign peptide bound to a major histocompatibility complex molecule (pMHC) displayed on the surface of altered cells. This recognition stimulates protection in the mammalian host against intracellular pathogens, including viruses, and involves piconewton forces that accompany pMHC ligation. Physical forces are generated by T-lymphocyte movement during immune surveillance as well as by cytoskeletal rearrangements at the immunological synapse following cessation of cell migration. The mechanistic explanation for how TCRs distinguish between foreign and self-peptides bound to a given MHC molecule is unclear: peptide residues themselves comprise few of the TCR contacts on the pMHC, and pathogen-derived peptides are scant among myriad self-peptides bound to the same MHC class arrayed on infected cells. Using optical tweezers and DNA tether spacer technology that permit piconewton force application and nanometer scale precision, we have determined how bioforces relate to self versus nonself discrimination. Single-molecule analyses involving isolated αβ-heterodimers as well as complete TCR complexes on T lymphocytes reveal that the FG loop in the β-subunit constant domain allosterically controls both the variable domain module's catch bond lifetime and peptide discrimination via force-driven conformational transition. In contrast to integrins, the TCR interrogates its ligand via a strong force-loaded state with release through a weakened, extended state. Our work defines a key element of TCR mechanotransduction, explaining why the FG loop structure evolved for adaptive immunity in αβ but not γδTCRs or immunoglobulins.
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36
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Abstract
αβ T-cell receptor (TCR) activation plays a crucial role for T-cell function. However, the TCR itself does not possess signaling domains. Instead, the TCR is noncovalently coupled to a conserved multisubunit signaling apparatus, the CD3 complex, that comprises the CD3εγ, CD3εδ, and CD3ζζ dimers. How antigen ligation by the TCR triggers CD3 activation and what structural role the CD3 extracellular domains (ECDs) play in the assembled TCR-CD3 complex remain unclear. Here, we use two complementary structural approaches to gain insight into the overall organization of the TCR-CD3 complex. Small-angle X-ray scattering of the soluble TCR-CD3εδ complex reveals the CD3εδ ECDs to sit underneath the TCR α-chain. The observed arrangement is consistent with EM images of the entire TCR-CD3 integral membrane complex, in which the CD3εδ and CD3εγ subunits were situated underneath the TCR α-chain and TCR β-chain, respectively. Interestingly, the TCR-CD3 transmembrane complex bound to peptide-MHC is a dimer in which two TCRs project outward from a central core composed of the CD3 ECDs and the TCR and CD3 transmembrane domains. This arrangement suggests a potential ligand-dependent dimerization mechanism for TCR signaling. Collectively, our data advance our understanding of the molecular organization of the TCR-CD3 complex, and provides a conceptual framework for the TCR activation mechanism.
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37
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Brazin KN, Mallis RJ, Li C, Keskin DB, Arthanari H, Gao Y, Wu SL, Karger BL, Wagner G, Reinherz EL. Constitutively oxidized CXXC motifs within the CD3 heterodimeric ectodomains of the T cell receptor complex enforce the conformation of juxtaposed segments. J Biol Chem 2014; 289:18880-92. [PMID: 24849600 PMCID: PMC4081929 DOI: 10.1074/jbc.m114.574996] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 05/19/2014] [Indexed: 11/06/2022] Open
Abstract
The CD3ϵγ and CD3ϵδ heterodimers along with the CD3ζζ homodimer are the signaling components of the T cell receptor (TCR). These invariant dimers are non-covalently associated on the T cell plasma membrane with a clone-specific (i.e. clonotypic) αβ heterodimer that binds its cognate ligand, a complex between a particular antigenic peptide, and an MHC molecule (pMHC). These four TCR dimers exist in a 1:1:1:1 stoichiometry. At the junction between the extracellular and transmembrane domains of each mammalian CD3ϵ, CD3γ, and CD3δ subunit is a highly conserved CXXC motif previously found to be important for thymocyte and T cell activation. The redox state of each CXXC motif is presently unknown. Here we show using LC-MS and a biotin switch assay that these CXXC segments are constitutively oxidized on resting and activated T cells, consistent with their measured reduction potential. NMR chemical shift perturbation experiments comparing a native oxidized CD3δ CXXC-containing segment with that of a mutant SXXS-containing CD3δ segment in LPPG (1-palmitoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (sodium salt)) micelles show extensive chemical shift differences in residues within the membrane-proximal motif as well as throughout the transmembrane and cytoplasmic domains as a result of the elimination of the native disulfide. Likewise, direct comparison of the native CD3δ segment in oxidizing and reducing conditions reveals numerous spectral differences. The oxidized CXXC maintains the structure within the membrane-proximal stalk region as well as that of its contiguous transmembrane and cytoplasmic domain, inclusive of the ITAM (immunoreceptor tyrosine-based activation motif) involved in signaling. These results suggest that preservation of the CD3 CXXC oxidized state may be essential for TCR mechanotransduction.
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Affiliation(s)
- Kristine N Brazin
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and Departments of Medicine and
| | - Robert J Mallis
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School and
| | - Chen Li
- Barnett Institute of Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115
| | - Derin B Keskin
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and
| | - Haribabu Arthanari
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School and
| | - Yuanwei Gao
- Barnett Institute of Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115
| | - Shiaw-Lin Wu
- Barnett Institute of Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115
| | - Barry L Karger
- Barnett Institute of Chemical and Biological Analysis, Northeastern University, Boston, Massachusetts 02115
| | - Gerhard Wagner
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School and
| | - Ellis L Reinherz
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and Departments of Medicine and
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38
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Berry R, Headey SJ, Call MJ, McCluskey J, Tregaskes CA, Kaufman J, Koh R, Scanlon MJ, Call ME, Rossjohn J. Structure of the chicken CD3εδ/γ heterodimer and its assembly with the αβT cell receptor. J Biol Chem 2014; 289:8240-51. [PMID: 24488493 DOI: 10.1074/jbc.m113.544965] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
In mammals, the αβT cell receptor (TCR) signaling complex is composed of a TCRαβ heterodimer that is noncovalently coupled to three dimeric signaling molecules, CD3εδ, CD3εγ, and CD3ζζ. The nature of the TCR signaling complex and subunit arrangement in different species remains unclear however. Here we present a structural and biochemical analysis of the more primitive ancestral form of the TCR signaling complex found in chickens. In contrast to mammals, chickens do not express separate CD3δ and CD3γ chains but instead encode a single hybrid chain, termed CD3δ/γ, that is capable of pairing with CD3ε. The NMR structure of the chicken CD3εδ/γ heterodimer revealed a unique dimer interface that results in a heterodimer with considerable deviation from the distinct side-by-side architecture found in human and murine CD3εδ and CD3εγ. The chicken CD3εδ/γ heterodimer also contains a unique molecular surface, with the vast majority of surface-exposed, nonconserved residues being clustered to a single face of the heterodimer. Using an in vitro biochemical assay, we demonstrate that CD3εδ/γ can assemble with both chicken TCRα and TCRβ via conserved polar transmembrane sites. Moreover, analogous to the human TCR signaling complex, the presence of two copies of CD3εδ/γ is required for ζζ assembly. These data provide insight into the evolution of this critical receptor signaling apparatus.
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Affiliation(s)
- Richard Berry
- From the Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
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Ferez M, Castro M, Alarcon B, van Santen HM. Cognate peptide-MHC complexes are expressed as tightly apposed nanoclusters in virus-infected cells to allow TCR crosslinking. THE JOURNAL OF IMMUNOLOGY 2013; 192:52-8. [PMID: 24307729 DOI: 10.4049/jimmunol.1301224] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Antigenic T cell stimulation requires interaction between the TCR of the T cell and cognate peptide-MHC molecules presented by the APC. Although studies with TCR-specific Abs and soluble peptide-MHC ligands have shown that the TCR needs to be crosslinked by two or more ligands to induce T cell stimulation, it is not understood how several MHC molecules loaded with the cognate antigenic peptide can produce crosslinking under physiological conditions. We show at the molecular level that large clusters of cognate peptide-MHC are formed at the surface of murine professional and nonprofessional APCs upon virus infection and that these clusters impinge on the stimulatory capacity of the APC. These clusters are formed by tight apposition of cognate peptide-MHC complexes in a configuration that is compatible with simultaneous engagement of two or more TCRs. This suggests that physiological expression of Ag allows formation of multivalent ligands for the TCR that permit TCR crosslinking and T cell activation.
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Affiliation(s)
- María Ferez
- Departamento de Biología Celular e Inmunología, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas/Universidad Autónoma de Madrid, 28049 Cantoblanco, Spain
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40
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Kuhns MS, Badgandi HB. Piecing together the family portrait of TCR-CD3 complexes. Immunol Rev 2013; 250:120-43. [PMID: 23046126 DOI: 10.1111/imr.12000] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The pre-T-cell receptor (TCR)-, αβTCR-, and γδTCR-CD3 complexes are members of a family of modular biosensors that are responsible for driving T-cell development, activation, and effector functions. They inform essential checkpoint decisions by relaying key information from their ligand-binding modules (TCRs) to their signaling modules (CD3γε + CD3δε and CD3ζζ) and on to the intracellular signaling apparatus. Their actions shape the T-cell repertoire, as well as T-cell-mediated immunity; yet, the mechanisms that underlie their activity remain an enigma. As with any molecular machine, understanding how they function depends upon understanding how their parts fit and work together. In the 30 years since the initial biochemical and genetic characterizations of the αβTCR, the structure and function of the individual components of these family members have been extensively characterized. Cumulatively, this information has allowed us to piece together a portrait of the αβTCR-CD3 complex and outline the form of the remaining family members. Here we review the known structural and functional characteristics of the components of these TCR-CD3 complex family members. We then discuss how these data have informed our understanding of the architecture of the αβTCR-CD3 complex as well as their implications for the other family members. The intent is to provide a framework for considering: (i) how these thematically similar complexes diverge to execute their specific functions and (ii) how our knowledge of the form and function of these distinct family members can cross-inform our understanding of the other family members.
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Affiliation(s)
- Michael S Kuhns
- Department of Immunobiology, The University of Arizona College of Medicine, Tucson, USA.
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41
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Abstract
Using an elaborately evolved language of cytokines and chemokines as well as cell-cell interactions, the different components of the immune system communicate with each other and orchestrate a response (or wind one down). Immunological synapses are a key feature of the system in the ways in which they can facilitate and direct these responses. Studies analyzing the structure of an immune synapse as it forms between two cells have provided insight into how the stability and kinetics of this interaction ultimately affect the sensitivity, potency, and magnitude of a given response. Furthermore, we have gained an appreciation of how the immunological synapse provides directionality and contextual cues for downstream signaling and cellular decision-making. In this review, we discuss how using a variety of techniques, developed over the last decade, have allowed us to visualize and quantify key aspects of the dynamic synaptic interface and have furthered our understanding of their function. We describe some of the many characteristics of the immunological synapse that make it a vital part of intercellular communication and some of the questions that remain to be answered.
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Affiliation(s)
- Jianming Xie
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
| | - Cristina M. Tato
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA, USA
| | - Mark M. Davis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA
- Institute for Immunity, Transplantation and Infection, Stanford University School of Medicine, Stanford, CA, USA
- The Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
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42
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Rossy J, Williamson DJ, Benzing C, Gaus K. The integration of signaling and the spatial organization of the T cell synapse. Front Immunol 2012. [PMID: 23189081 PMCID: PMC3504718 DOI: 10.3389/fimmu.2012.00352] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Engagement of the T cell antigen receptor (TCR) triggers signaling pathways that lead to T cell selection, differentiation and clonal expansion. Superimposed onto the biochemical network is a spatial organization that describes individual receptor molecules, dimers, oligomers and higher order structures. Here we discuss recent findings and new concepts that may regulate TCR organization in naïve and memory T cells. A key question that has emerged is how antigen-TCR interactions encode spatial information to direct T cell activation and differentiation. Single molecule super-resolution microscopy may become an important tool in decoding receptor organization at the molecular level.
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Affiliation(s)
- Jérémie Rossy
- Centre for Vascular Research and Australian Centre for Nanomedicine, University of New South Wales Sydney, NSW, Australia
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43
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Wang JH, Reinherz EL. The structural basis of αβ T-lineage immune recognition: TCR docking topologies, mechanotransduction, and co-receptor function. Immunol Rev 2012; 250:102-19. [PMID: 23046125 PMCID: PMC3694212 DOI: 10.1111/j.1600-065x.2012.01161.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Self versus non-self discrimination is at the core of T-lymphocyte recognition. To this end, αβ T-cell receptors (TCRs) ligate 'foreign' peptides bound to major histocompatibility complex (MHC) class I or class II molecules (pMHC) arrayed on the surface of antigen-presenting cells (APCs). Since the discovery of TCRs approximately 30 years ago, considerable structural and functional data have detailed the molecular basis of their extraordinary ligand specificity and sensitivity in mediating adaptive T-cell immunity. This review focuses on the structural biology of the Fab-like TCRαβ clonotypic heterodimer and its unique features in conjunction with those of the associated CD3εγ and CD3εδ heterodimeric molecules, which, along with CD3ζζ homodimer, comprise the TCR complex in a stoichiometry of 1:1:1:1. The basis of optimized TCRαβ docking geometry on the pMHC linked to TCR mechanotransduction and required for T-cell signaling as well as CD4 and CD8 co-receptor function is detailed. A model of the TCR ectodomain complex including its connecting peptides suggests how force generated during T-cell immune surveillance and at the immunological synapse results in dynamic TCR quaternary change involving its heterodimeric components. Potential insights from the structural biology relevant to immunity and immunosuppression are revealed.
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MESH Headings
- Animals
- Antigen-Presenting Cells/cytology
- Antigen-Presenting Cells/immunology
- Antigen-Presenting Cells/metabolism
- Antigens/chemistry
- Antigens/immunology
- Antigens/metabolism
- CD3 Complex/chemistry
- CD3 Complex/immunology
- CD3 Complex/metabolism
- CD4-Positive T-Lymphocytes/cytology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/cytology
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- Humans
- Major Histocompatibility Complex/immunology
- Mechanotransduction, Cellular
- Mice
- Models, Molecular
- Peptides/chemistry
- Peptides/immunology
- Peptides/metabolism
- Protein Conformation
- Protein Multimerization
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
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Affiliation(s)
- Jia-huai Wang
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, Boston, MA, USA
| | - Ellis L. Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Medicine, Harvard Medical School, Boston, MA, USA
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44
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Gras S, Burrows SR, Turner SJ, Sewell AK, McCluskey J, Rossjohn J. A structural voyage toward an understanding of the MHC-I-restricted immune response: lessons learned and much to be learned. Immunol Rev 2012; 250:61-81. [DOI: 10.1111/j.1600-065x.2012.01159.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stephanie Gras
- Department of Biochemistry and Molecular Biology; School of Biomedical Sciences; Monash University; Clayton; Australia
| | - Scott R. Burrows
- Queensland Institute of Medical Research and Australian Centre for Vaccine Development; Brisbane; Australia
| | - Stephen J. Turner
- Department of Microbiology and Immunology; University of Melbourne; Parkville; Australia
| | - Andrew K. Sewell
- Institute of Infection and Immunity; Cardiff University School of Medicine; Cardiff; UK
| | - James McCluskey
- Department of Microbiology and Immunology; University of Melbourne; Parkville; Australia
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45
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Kuhns MS, Davis MM. TCR Signaling Emerges from the Sum of Many Parts. Front Immunol 2012; 3:159. [PMID: 22737151 PMCID: PMC3381686 DOI: 10.3389/fimmu.2012.00159] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2012] [Accepted: 05/27/2012] [Indexed: 11/30/2022] Open
Abstract
“How does T cell receptor signaling begin?” Answering this question requires an understanding of how the parts of the molecular machinery that mediates this process fit and work together. Ultimately this molecular architecture must (i) trigger the relay of information from the TCR-pMHC interface to the signaling substrates of the CD3 molecules and (ii) bring the kinases that modify these substrates in close proximity to interact, initiate, and sustain signaling. In this contribution we will discuss advances of the last decade that have increased our understanding of the complex machinery and interactions that underlie this type of signaling.
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Affiliation(s)
- Michael S Kuhns
- Department of Immunobiology, The University of Arizona College of Medicine Tucson, AZ, USA
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46
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Zhong Y, Fang S. Live cell imaging of protein dislocation from the endoplasmic reticulum. J Biol Chem 2012; 287:28057-66. [PMID: 22722934 DOI: 10.1074/jbc.m112.381798] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Misfolded proteins in the endoplasmic reticulum (ER) are dislocated to the cytosol to be degraded by the proteasomes. Various plant and bacterial toxins and certain viruses hijack this dislocation pathway to exert their toxicity or to infect cells. In this study, we report a dislocation-dependent reconstituted GFP (drGFP) assay that allows, for the first time, imaging proteins dislocated from the ER lumen to the cytosol in living cells. Our results indicate that both luminal and membrane-spanning ER proteins can be fully dislocated from the ER to the cytosol. By combining the drGFP assay with RNAi or chemical inhibitors of proteins in the Hrd1 ubiquitin ligase complex, we demonstrate that the Sel1L, Hrd1, p97/VCP, and importin β proteins are required for the dislocation of misfolded luminal α-1 antitrypsin. The strategy described in this work is broadly applicable to the study of other types of transmembrane transport of proteins and likely also of viruses and toxins in living cells.
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Affiliation(s)
- Yongwang Zhong
- Center for Biomedical Engineering and Technology and Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA
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47
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Blanco R, Alarcón B. TCR Nanoclusters as the Framework for Transmission of Conformational Changes and Cooperativity. Front Immunol 2012; 3:115. [PMID: 22582078 PMCID: PMC3348506 DOI: 10.3389/fimmu.2012.00115] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 04/22/2012] [Indexed: 12/30/2022] Open
Abstract
Increasing evidence favors the notion that, before triggering, the T cell antigen receptor (TCR) forms nanometer-scale oligomers that are called nanoclusters. The organization of the TCR in pre-existing oligomers cannot be ignored when analyzing the properties of ligand (pMHC) recognition and signal transduction. As with other membrane receptors, the existence of TCR oligomers points out to cooperativity phenomena. We review the data in support of conformational changes in the TCR as the basic principle to transduce the activation signal to the cytoplasm and the incipient data suggesting cooperativity within nanoclusters.
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Affiliation(s)
- Raquel Blanco
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid Madrid, Spain
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48
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Kim ST, Shin Y, Brazin K, Mallis RJ, Sun ZYJ, Wagner G, Lang MJ, Reinherz EL. TCR Mechanobiology: Torques and Tunable Structures Linked to Early T Cell Signaling. Front Immunol 2012; 3:76. [PMID: 22566957 PMCID: PMC3342345 DOI: 10.3389/fimmu.2012.00076] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Accepted: 03/27/2012] [Indexed: 11/16/2022] Open
Abstract
Mechanotransduction is a basis for receptor signaling in many biological systems. Recent data based upon optical tweezer experiments suggest that the TCR is an anisotropic mechanosensor, converting mechanical energy into biochemical signals upon specific peptide-MHC complex (pMHC) ligation. Tangential force applied along the pseudo-twofold symmetry axis of the TCR complex post-ligation results in the αβ heterodimer exerting torque on the CD3 heterodimers as a consequence of molecular movement at the T cell-APC interface. Accompanying TCR quaternary change likely fosters signaling via the lipid bilayer predicated on the magnitude and direction of the TCR-pMHC force. TCR glycans may modulate quaternary change, thereby altering signaling outcome as might the redox state of the CxxC motifs located proximal to the TM segments in the heterodimeric CD3 subunits. Predicted alterations in TCR TM segments and surrounding lipid will convert ectodomain ligation into the earliest intracellular signaling events.
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Affiliation(s)
- Sun Taek Kim
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical SchoolBoston, MA, USA
- Department of Medicine, Harvard Medical SchoolBoston, MA, USA
| | - Yongdae Shin
- Department of Mechanical Engineering, Massachusetts Institute of Technology, CambridgeMA, USA
| | - Kristine Brazin
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical SchoolBoston, MA, USA
- Department of Medicine, Harvard Medical SchoolBoston, MA, USA
| | - Robert J. Mallis
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical SchoolBoston, MA, USA
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBoston, MA, USA
| | - Zhen-Yu J. Sun
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBoston, MA, USA
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical SchoolBoston, MA, USA
| | - Matthew J. Lang
- Department of Chemical and Biomolecular Engineering, Vanderbilt UniversityNashville, TN, USA
| | - Ellis L. Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical SchoolBoston, MA, USA
- Department of Medicine, Harvard Medical SchoolBoston, MA, USA
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49
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Fernandes RA, Shore DA, Vuong MT, Yu C, Zhu X, Pereira-Lopes S, Brouwer H, Fennelly JA, Jessup CM, Evans EJ, Wilson IA, Davis SJ. T cell receptors are structures capable of initiating signaling in the absence of large conformational rearrangements. J Biol Chem 2012; 287:13324-35. [PMID: 22262845 PMCID: PMC3339974 DOI: 10.1074/jbc.m111.332783] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 01/10/2012] [Indexed: 12/18/2022] Open
Abstract
Native and non-native ligands of the T cell receptor (TCR), including antibodies, have been proposed to induce signaling in T cells via intra- or intersubunit conformational rearrangements within the extracellular regions of TCR complexes. We have investigated whether any signatures can be found for such postulated structural changes during TCR triggering induced by antibodies, using crystallographic and mutagenesis-based approaches. The crystal structure of murine CD3ε complexed with the mitogenic anti-CD3ε antibody 2C11 enabled the first direct structural comparisons of antibody-liganded and unliganded forms of CD3ε from a single species, which revealed that antibody binding does not induce any substantial rearrangements within CD3ε. Saturation mutagenesis of surface-exposed CD3ε residues, coupled with assays of antibody-induced signaling by the mutated complexes, suggests a new configuration for the complex within which CD3ε is highly exposed and reveals that no large new CD3ε interfaces are required to form during antibody-induced signaling. The TCR complex therefore appears to be a structure that is capable of initiating intracellular signaling in T cells without substantial structural rearrangements within or between the component subunits. Our findings raise the possibility that signaling by native ligands might also be initiated in the absence of large structural rearrangements in the receptor.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- CD3 Complex/chemistry
- CD3 Complex/genetics
- CD3 Complex/immunology
- Crystallography, X-Ray
- Dimerization
- Epitopes, T-Lymphocyte/immunology
- Humans
- Immunoglobulin Fab Fragments/immunology
- Jurkat Cells
- Mice
- Mutagenesis, Site-Directed
- Protein Conformation
- Protein Structure, Tertiary
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/immunology
- Receptors, Antigen, T-Cell/metabolism
- Signal Transduction/immunology
- Structure-Activity Relationship
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Affiliation(s)
- Ricardo A. Fernandes
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - David A. Shore
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Mai T. Vuong
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Chao Yu
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Xueyong Zhu
- the Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Selma Pereira-Lopes
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Heather Brouwer
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Janet A. Fennelly
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Claire M. Jessup
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Edward J. Evans
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
| | - Ian A. Wilson
- the Department of Molecular Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Simon J. Davis
- From the Nuffield Department of Clinical Medicine and Medical Research Council Human Immunology Unit, The University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DU, United Kingdom and
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50
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Gascoigne NRJ, Casas J, Brzostek J, Rybakin V. Initiation of TCR phosphorylation and signal transduction. Front Immunol 2011; 2:72. [PMID: 22566861 PMCID: PMC3342367 DOI: 10.3389/fimmu.2011.00072] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Accepted: 11/21/2011] [Indexed: 01/14/2023] Open
Abstract
Recent data with CD8+ T cells show that the initial phase of T cell receptor (TCR) binding to MHC–peptide (MHCp) is quickly followed by a second, stronger, binding phase representing the binding of CD8 to the MHCp. This second phase requires signaling by a Src-family kinase such as Lck. These data point out two aspects of the initial stage of TCR signaling that have not yet been clearly resolved. Firstly, how and by which Src-family kinase, is the initial phosphorylation of CD3ζ accomplished, given that the Lck associated with the co-receptors (CD4 or CD8) is not yet available. Secondly, what is the mechanism by which the co-receptor is brought close to the bound TCR before the co-receptor binds to MHCp?
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Affiliation(s)
- Nicholas R J Gascoigne
- Department of Immunology and Microbial Science, The Scripps Research Institute La Jolla, CA, USA.
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