1
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Rogers J, Bajur AT, Salaita K, Spillane KM. Mechanical control of antigen detection and discrimination by T and B cell receptors. Biophys J 2024:S0006-3495(24)00347-3. [PMID: 38794795 DOI: 10.1016/j.bpj.2024.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 05/10/2024] [Accepted: 05/21/2024] [Indexed: 05/26/2024] Open
Abstract
The adaptive immune response is orchestrated by just two cell types, T cells and B cells. Both cells possess the remarkable ability to recognize virtually any antigen through their respective antigen receptors-the T cell receptor (TCR) and B cell receptor (BCR). Despite extensive investigations into the biochemical signaling events triggered by antigen recognition in these cells, our ability to predict or control the outcome of T and B cell activation remains elusive. This challenge is compounded by the sensitivity of T and B cells to the biophysical properties of antigens and the cells presenting them-a phenomenon we are just beginning to understand. Recent insights underscore the central role of mechanical forces in this process, governing the conformation, signaling activity, and spatial organization of TCRs and BCRs within the cell membrane, ultimately eliciting distinct cellular responses. Traditionally, T cells and B cells have been studied independently, with researchers working in parallel to decipher the mechanisms of activation. While these investigations have unveiled many overlaps in how these cell types sense and respond to antigens, notable differences exist. To fully grasp their biology and harness it for therapeutic purposes, these distinctions must be considered. This review compares and contrasts the TCR and BCR, placing emphasis on the role of mechanical force in regulating the activity of both receptors to shape cellular and humoral adaptive immune responses.
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Affiliation(s)
- Jhordan Rogers
- Department of Chemistry, Emory University, Atlanta, Georgia
| | - Anna T Bajur
- Department of Physics, King's College London, London, United Kingdom; Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Khalid Salaita
- Department of Chemistry, Emory University, Atlanta, Georgia; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia.
| | - Katelyn M Spillane
- Department of Physics, King's College London, London, United Kingdom; Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom; Department of Life Sciences, Imperial College London, London, United Kingdom.
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2
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Acuto O. T-cell virtuosity in ''knowing thyself". Front Immunol 2024; 15:1343575. [PMID: 38415261 PMCID: PMC10896960 DOI: 10.3389/fimmu.2024.1343575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 01/17/2024] [Indexed: 02/29/2024] Open
Abstract
Major Histocompatibility Complex (MHC) I and II and the αβ T-cell antigen receptor (TCRαβ) govern fundamental traits of adaptive immunity. They form a membrane-borne ligand-receptor system weighing host proteome integrity to detect contamination by nonself proteins. MHC-I and -II exhibit the "MHC-fold", which is able to bind a large assortment of short peptides as proxies for self and nonself proteins. The ensuing varying surfaces are mandatory ligands for Ig-like TCRαβ highly mutable binding sites. Conserved molecular signatures guide TCRαβ ligand binding sites to focus on the MHC-fold (MHC-restriction) while leaving many opportunities for its most hypervariable determinants to contact the peptide. This riveting molecular strategy affords many options for binding energy compatible with specific recognition and signalling aimed to eradicated microbial pathogens and cancer cells. While the molecular foundations of αβ T-cell adaptive immunity are largely understood, uncertainty persists on how peptide-MHC binding induces the TCRαβ signals that instruct cell-fate decisions. Solving this mystery is another milestone for understanding αβ T-cells' self/nonself discrimination. Recent developments revealing the innermost links between TCRαβ structural dynamics and signalling modality should help dissipate this long-sought-after enigma.
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Affiliation(s)
- Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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3
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McShan AC, Flores-Solis D, Sun Y, Garfinkle SE, Toor JS, Young MC, Sgourakis NG. Conformational plasticity of RAS Q61 family of neoepitopes results in distinct features for targeted recognition. Nat Commun 2023; 14:8204. [PMID: 38081856 PMCID: PMC10713829 DOI: 10.1038/s41467-023-43654-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 11/15/2023] [Indexed: 12/18/2023] Open
Abstract
The conformational landscapes of peptide/human leucocyte antigen (pHLA) protein complexes encompassing tumor neoantigens provide a rationale for target selection towards autologous T cell, vaccine, and antibody-based therapeutic modalities. Here, using complementary biophysical and computational methods, we characterize recurrent RAS55-64 Q61 neoepitopes presented by the common HLA-A*01:01 allotype. We integrate sparse NMR restraints with Rosetta docking to determine the solution structure of NRASQ61K/HLA-A*01:01, which enables modeling of other common RAS55-64 neoepitopes. Hydrogen/deuterium exchange mass spectrometry experiments alongside molecular dynamics simulations reveal differences in solvent accessibility and conformational plasticity across a panel of common Q61 neoepitopes that are relevant for recognition by immunoreceptors. Finally, we predict binding and provide structural models of NRASQ61K antigens spanning the entire HLA allelic landscape, together with in vitro validation for HLA-A*01:191, HLA-B*15:01, and HLA-C*08:02. Our work provides a basis to delineate the solution surface features and immunogenicity of clinically relevant neoepitope/HLA targets for cancer therapy.
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Affiliation(s)
- Andrew C McShan
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr NW, Atlanta, GA, 30318, USA
| | - David Flores-Solis
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, 95064, USA
- German Center for Neurodegenerative Diseases (DZNE), Von-Siebold Straße 3A, 37075, Göttingen, Germany
| | - Yi Sun
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Samuel E Garfinkle
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Jugmohit S Toor
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, 95064, USA
- Immunology Research Program, Henry Ford Cancer Institute, Henry Ford Health, Detroit, MI, 48202, USA
| | - Michael C Young
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Nikolaos G Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA.
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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4
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Ayres CM, Corcelli SA, Baker BM. The Energetic Landscape of Catch Bonds in TCR Interfaces. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:325-332. [PMID: 37459192 PMCID: PMC10361606 DOI: 10.4049/jimmunol.2300121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/14/2023] [Indexed: 07/20/2023]
Abstract
Recognition of peptide/MHC complexes by αβ TCRs has traditionally been viewed through the lens of conventional receptor-ligand theory. Recent work, however, has shown that TCR recognition and T cell signaling can be profoundly influenced and tuned by mechanical forces. One outcome of applied force is the catch bond, where TCR dissociation rates decrease (half-lives increase) when limited force is applied. Although catch bond behavior is believed to be widespread in biology, its counterintuitive nature coupled with the difficulties of describing mechanisms at the structural level have resulted in considerable mystique. In this review, we demonstrate that viewing catch bonds through the lens of energy landscapes, barriers, and the ensuing reaction rates can help demystify catch bonding and provide a foundation on which atomic-level TCR catch bond mechanisms can be built.
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Affiliation(s)
- Cory M Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
- The Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN
| | - Steve A Corcelli
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
- The Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN
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5
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Patskovsky Y, Natarajan A, Patskovska L, Nyovanie S, Joshi B, Morin B, Brittsan C, Huber O, Gordon S, Michelet X, Schmitzberger F, Stein RB, Findeis MA, Hurwitz A, Van Dijk M, Chantzoura E, Yague AS, Pollack Smith D, Buell JS, Underwood D, Krogsgaard M. Molecular mechanism of phosphopeptide neoantigen immunogenicity. Nat Commun 2023; 14:3763. [PMID: 37353482 PMCID: PMC10290117 DOI: 10.1038/s41467-023-39425-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 06/12/2023] [Indexed: 06/25/2023] Open
Abstract
Altered protein phosphorylation in cancer cells often leads to surface presentation of phosphopeptide neoantigens. However, their role in cancer immunogenicity remains unclear. Here we describe a mechanism by which an HLA-B*0702-specific acute myeloid leukemia phosphoneoantigen, pMLL747-755 (EPR(pS)PSHSM), is recognized by a cognate T cell receptor named TCR27, a candidate for cancer immunotherapy. We show that the replacement of phosphoserine P4 with serine or phosphomimetics does not affect pMHC conformation or peptide-MHC affinity but abrogates TCR27-dependent T cell activation and weakens binding between TCR27 and pMHC. Here we describe the crystal structures for TCR27 and cognate pMHC, map of the interface produced by nuclear magnetic resonance, and a ternary complex generated using information-driven protein docking. Our data show that non-covalent interactions between the epitope phosphate group and TCR27 are crucial for TCR specificity. This study supports development of new treatment options for cancer patients through target expansion and TCR optimization.
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Grants
- P30 GM133893 NIGMS NIH HHS
- P30 CA016087 NCI NIH HHS
- U01 CA214354 NCI NIH HHS
- P50 CA225450 NCI NIH HHS
- R01 GM085586 NIGMS NIH HHS
- R01 GM124489 NIGMS NIH HHS
- R01 CA243486 NCI NIH HHS
- S10 OD016343 NIH HHS
- P41 GM118302 NIGMS NIH HHS
- U.S. Department of Health & Human Services | NIH | National Cancer Institute (NCI)
- This work was supported by the NIH grant NIGMS R01 GM124489 (to M.K.), NCI R01 CA243486 (to M.K) and a Sponsored Research Agreement from Agenus to M.K. Results shown in this report are partially derived from work performed at Argonne National Laboratory, Structural Biology Center at the Advanced Photon Source. SBC is operated by UChicago Argonne, LLC, for the U.S. Department of Energy, Office of Biological and Environmental Research under contract DE-AC02-06CH11357. Results in this report are partially derived from work performed at The Center for BioMolecular Structure (CBMS) primarily supported by the National Institutes of Health, National Institute of General Medical Sciences (NIGMS) through a Center Core P30 Grant (P30GM133893), and by the DOE Office of Biological and Environmental Research (KP1607011). As part of NSLS-II, a national user facility at Brookhaven National Laboratory, work performed at the CBMS is supported in part by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences Program under contract number and DE-SC0012704. The NMR spectrometers at the NYU Chemistry Shared Instrumentation Facility were supported by NYU and the NIH Grant 1S10-OD016343. The facilities at the NYSBC were supported by the NIH Grant P41GM118302.
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Affiliation(s)
- Yury Patskovsky
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, USA
- Laura and Isaac Perlmutter Cancer Center at NYU Langone Health, New York, NY, USA
| | - Aswin Natarajan
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, USA
- Laura and Isaac Perlmutter Cancer Center at NYU Langone Health, New York, NY, USA
| | - Larysa Patskovska
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, USA
- Laura and Isaac Perlmutter Cancer Center at NYU Langone Health, New York, NY, USA
| | - Samantha Nyovanie
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, USA
- Laura and Isaac Perlmutter Cancer Center at NYU Langone Health, New York, NY, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Michelle Krogsgaard
- Department of Pathology, New York University Grossman School of Medicine, New York, NY, USA.
- Laura and Isaac Perlmutter Cancer Center at NYU Langone Health, New York, NY, USA.
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6
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Thomas C, Tampé R. Structure and mechanism of immunoreceptors: New horizons in T cell and B cell receptor biology and beyond. Curr Opin Struct Biol 2023; 80:102570. [PMID: 36940642 DOI: 10.1016/j.sbi.2023.102570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Revised: 01/15/2023] [Accepted: 02/07/2023] [Indexed: 03/23/2023]
Abstract
Immunoreceptors, also named non-catalytic tyrosine-phosphorylated receptors, are a large class of leukocyte cell-surface proteins critically involved in innate and adaptive immune responses. Their most characteristic defining feature is a shared signal transduction machinery where binding events of cell surface-anchored ligands to the small extracellular receptor domains are translated into phosphorylation of conserved tyrosine-containing cytosolic sequence motifs initiating downstream signal transduction cascades. Despite their central importance to immunology, the molecular mechanism of how ligand binding activates the receptors and results in robust intracellular signaling has remained enigmatic. Recent breakthroughs in our understanding of the architecture and triggering mechanism of immunoreceptors come from cryogenic electron microscopy studies of the B cell and T cell antigen receptors.
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Affiliation(s)
- Christoph Thomas
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt/Main, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt/Main, Germany.
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7
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Papadaki GF, Ani O, Florio TJ, Young MC, Danon JN, Sun Y, Dersh D, Sgourakis NG. Decoupling peptide binding from T cell receptor recognition with engineered chimeric MHC-I molecules. Front Immunol 2023; 14:1116906. [PMID: 36761745 PMCID: PMC9905809 DOI: 10.3389/fimmu.2023.1116906] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/10/2023] [Indexed: 01/26/2023] Open
Abstract
Major Histocompatibility Complex class I (MHC-I) molecules display self, viral or aberrant epitopic peptides to T cell receptors (TCRs), which employ interactions between complementarity-determining regions with both peptide and MHC-I heavy chain 'framework' residues to recognize specific Human Leucocyte Antigens (HLAs). The highly polymorphic nature of the HLA peptide-binding groove suggests a malleability of interactions within a common structural scaffold. Here, using structural data from peptide:MHC-I and pMHC:TCR structures, we first identify residues important for peptide and/or TCR binding. We then outline a fixed-backbone computational design approach for engineering synthetic molecules that combine peptide binding and TCR recognition surfaces from existing HLA allotypes. X-ray crystallography demonstrates that chimeric molecules bridging divergent HLA alleles can bind selected peptide antigens in a specified backbone conformation. Finally, in vitro tetramer staining and biophysical binding experiments using chimeric pMHC-I molecules presenting established antigens further demonstrate the requirement of TCR recognition on interactions with HLA framework residues, as opposed to interactions with peptide-centric Chimeric Antigen Receptors (CARs). Our results underscore a novel, structure-guided platform for developing synthetic HLA molecules with desired properties as screening probes for peptide-centric interactions with TCRs and other therapeutic modalities.
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Affiliation(s)
- Georgia F. Papadaki
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Omar Ani
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Tyler J. Florio
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Michael C. Young
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Julia N. Danon
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Yi Sun
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Devin Dersh
- Department of Radiation Oncology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Nikolaos G. Sgourakis
- Center for Computational and Genomic Medicine, Department of Pathology and Laboratory Medicine, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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8
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Rushdi MN, Pan V, Li K, Choi HK, Travaglino S, Hong J, Griffitts F, Agnihotri P, Mariuzza RA, Ke Y, Zhu C. Cooperative binding of T cell receptor and CD4 to peptide-MHC enhances antigen sensitivity. Nat Commun 2022; 13:7055. [PMID: 36396644 PMCID: PMC9671906 DOI: 10.1038/s41467-022-34587-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 10/29/2022] [Indexed: 11/19/2022] Open
Abstract
Antigen recognition by the T cell receptor (TCR) of CD4+ T cells can be greatly enhanced by the coreceptor CD4. Yet, understanding of the molecular mechanism is hindered by the ultra-low affinity of CD4 binding to class-II peptide-major histocompatibility complexes (pMHC). Here we show, using two-dimensional (2D) mechanical-based assays, that the affinity of CD4-pMHC interaction is 3-4 logs lower than that of cognate TCR-pMHC interactions, and it is more susceptible to increased dissociation by forces (slip bond). In contrast, CD4 binds TCR-pre-bound pMHC at 3-6 logs higher affinity, forming TCR-pMHC-CD4 tri-molecular bonds that are prolonged by force (catch bond), and modulated by protein mobility on the cell membrane, indicating profound TCR-CD4 cooperativity. Consistent with a tri-crystal structure, using DNA origami as a molecular ruler to titrate spacing between TCR and CD4 we show that 7-nm proximity optimizes TCR-pMHC-CD4 tri-molecular bond formation with pMHC. Our results thus provide deep mechanistic insight into CD4 enhancement of TCR antigen recognition.
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Affiliation(s)
- Muaz Nik Rushdi
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA ,grid.419673.e0000 0000 9545 2456Present Address: Medtronic CO., Minneapolis, MN USA
| | - Victor Pan
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA ,grid.510306.10000 0004 5907 6472Present Address: Intellia Therapeutics, Cambridge, MA USA
| | - Kaitao Li
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA
| | - Hyun-Kyu Choi
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA
| | - Stefano Travaglino
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA
| | - Jinsung Hong
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA ,grid.417587.80000 0001 2243 3366Present Address: Food and Drug Administration, Silver Spring, MD USA
| | - Fletcher Griffitts
- grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Georgia W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA USA
| | - Pragati Agnihotri
- grid.440664.40000 0001 0313 4029W. M. Keck Laboratory for Structural Biology, Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD USA ,grid.164295.d0000 0001 0941 7177Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD USA ,grid.281126.e0000 0004 0612 4549Present Address: Advanced Bioscience Laboratories, Rockville, MD USA
| | - Roy A. Mariuzza
- grid.440664.40000 0001 0313 4029W. M. Keck Laboratory for Structural Biology, Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD USA ,grid.164295.d0000 0001 0941 7177Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD USA
| | - Yonggang Ke
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.189967.80000 0001 0941 6502Medical Scientist Training Program, Emory University School of Medicine, Atlanta, GA USA
| | - Cheng Zhu
- grid.213917.f0000 0001 2097 4943Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Parker H. Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA USA ,grid.213917.f0000 0001 2097 4943Georgia W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA USA
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9
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Structural mechanism of tapasin-mediated MHC-I peptide loading in antigen presentation. Nat Commun 2022; 13:5470. [PMID: 36115831 PMCID: PMC9482634 DOI: 10.1038/s41467-022-33153-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 08/26/2022] [Indexed: 11/08/2022] Open
Abstract
AbstractLoading of MHC-I molecules with peptide by the catalytic chaperone tapasin in the peptide loading complex plays a critical role in antigen presentation and immune recognition. Mechanistic insight has been hampered by the lack of detailed structural information concerning tapasin–MHC-I. We present here crystal structures of human tapasin complexed with the MHC-I molecule HLA-B*44:05, and with each of two anti-tapasin antibodies. The tapasin-stabilized peptide-receptive state of HLA-B*44:05 is characterized by distortion of the peptide binding groove and destabilization of the β2-microglobulin interaction, leading to release of peptide. Movements of the membrane proximal Ig-like domains of tapasin, HLA-B*44:05, and β2-microglobulin accompany the transition to a peptide-receptive state. Together this ensemble of crystal structures provides insights into a distinct mechanism of tapasin-mediated peptide exchange.
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10
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Sušac L, Vuong MT, Thomas C, von Bülow S, O'Brien-Ball C, Santos AM, Fernandes RA, Hummer G, Tampé R, Davis SJ. Structure of a fully assembled tumor-specific T cell receptor ligated by pMHC. Cell 2022; 185:3201-3213.e19. [PMID: 35985289 PMCID: PMC9630439 DOI: 10.1016/j.cell.2022.07.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 04/05/2022] [Accepted: 07/15/2022] [Indexed: 12/12/2022]
Abstract
The T cell receptor (TCR) expressed by T lymphocytes initiates protective immune responses to pathogens and tumors. To explore the structural basis of how TCR signaling is initiated when the receptor binds to peptide-loaded major histocompatibility complex (pMHC) molecules, we used cryogenic electron microscopy to determine the structure of a tumor-reactive TCRαβ/CD3δγε2ζ2 complex bound to a melanoma-specific human class I pMHC at 3.08 Å resolution. The antigen-bound complex comprises 11 subunits stabilized by multivalent interactions across three structural layers, with clustered membrane-proximal cystines stabilizing the CD3-εδ and CD3-εγ heterodimers. Extra density sandwiched between transmembrane helices reveals the involvement of sterol lipids in TCR assembly. The geometry of the pMHC/TCR complex suggests that efficient TCR scanning of pMHC requires accurate pre-positioning of T cell and antigen-presenting cell membranes. Comparisons of the ligand-bound and unliganded receptors, along with molecular dynamics simulations, indicate that TCRs can be triggered in the absence of spontaneous structural rearrangements.
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Affiliation(s)
- Lukas Sušac
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Mai T Vuong
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK; Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Christoph Thomas
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Sören von Bülow
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Caitlin O'Brien-Ball
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK; Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Ana Mafalda Santos
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK; Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Ricardo A Fernandes
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK; Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Gerhard Hummer
- Department of Theoretical Biophysics, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany; Institute of Biophysics, Goethe University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt am Main, Germany
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany.
| | - Simon J Davis
- Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK; Medical Research Council Human Immunology Unit, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK.
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11
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Grimholt U, Sundaram AYM, Bøe CA, Dahle MK, Lukacs M. Tetraploid Ancestry Provided Atlantic Salmon With Two Paralogue Functional T Cell Receptor Beta Regions Whereof One Is Completely Novel. Front Immunol 2022; 13:930312. [PMID: 35784332 PMCID: PMC9247247 DOI: 10.3389/fimmu.2022.930312] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 05/23/2022] [Indexed: 11/13/2022] Open
Abstract
Protective cellular immune responses have been difficult to study in fish, due to lack of basic understanding of their T cell populations, and tools to study them. Cellular immunity is thus mostly ignored in vaccination and infection studies compared to humoral responses. High throughput sequencing, as well as access to well assembled genomes, now advances studies of cellular responses. Here we have used such resources to describe organization of T cell receptor beta genes in Atlantic salmon. Salmonids experienced a unique whole genome duplication approximately 94 million years ago, which provided these species with many functional duplicate genes, where some duplicates have evolved new functions or sub-functions of the original gene copy. This is also the case for T cell receptor beta, where Atlantic salmon has retained two paralogue T cell receptor beta regions on chromosomes 01 and 09. Compared to catfish and zebrafish, the genomic organization in both regions is unique, each chromosomal region organized with dual variable- diversity- joining- constant genes in a head to head orientation. Sequence identity of the chromosomal constant sequences between TRB01 and TRB09 is suggestive of rapid diversification, with only 67 percent as opposed to the average 82-90 percent for other duplicated genes. Using virus challenged samples we find both regions expressing bona fide functional T cell receptor beta molecules. Adding the 292 variable T cell receptor alpha genes to the 100 variable TRB genes from 14 subgroups, Atlantic salmon has one of the most diverse T cell receptor alpha beta repertoire of any vertebrate studied so far. Perhaps salmonid cellular immunity is more advanced than we have imagined.
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Affiliation(s)
- Unni Grimholt
- Fish Health Research Section, Norwegian Veterinary Institute, Oslo, Norway
- *Correspondence: Unni Grimholt,
| | - Arvind Y. M. Sundaram
- Fish Health Research Section, Norwegian Veterinary Institute, Oslo, Norway
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | | | - Maria K. Dahle
- Fish Health Research Section, Norwegian Veterinary Institute, Oslo, Norway
| | - Morten Lukacs
- Fish Health Research Section, Norwegian Veterinary Institute, Oslo, Norway
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12
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Hou J, Jiang X, Yang F, Wang L, Yan T, Liu S, Xu J, Hou C, Luo Q, Liu J. Supramolecularly regulated artificial transmembrane signal transduction for 'ON/OFF'-switchable enzyme catalysis. Chem Commun (Camb) 2022; 58:5725-5728. [PMID: 35441622 DOI: 10.1039/d2cc01421a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
An artificial signal transduction model with a supramolecular recognition headgroup, a membrane anchoring group, and a pro-enzyme catalysis endgroup was constructed. The transmembrane translocation of the transducer can be reversibly regulated by competitive host-guest complexations as an input signal to control an enzyme reaction inside the lipid vesicles.
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Affiliation(s)
- Jinxing Hou
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, China.
| | - Xiaojia Jiang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, China.
| | - Feihu Yang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, China.
| | - Liang Wang
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, China.
| | - Tengfei Yan
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China
| | - Shengda Liu
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China
| | - Jiayun Xu
- College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China
| | - Chunxi Hou
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, China.
| | - Quan Luo
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, China. .,Key Laboratory for Molecular Enzymology and Engineering of Ministry of Education, School of Life Sciences, Jilin University, Changchun 130012, China.,Key Laboratory of Emergency and Trauma, Ministry of Education, College of Emergency and Trauma, Hainan Medical University, Haikou 571199, China
| | - Junqiu Liu
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, 2699 Qianjin Road, Changchun 130012, China. .,College of Material, Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou 311121, China
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13
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The Full Model of the pMHC-TCR-CD3 Complex: A Structural and Dynamical Characterization of Bound and Unbound States. Cells 2022; 11:cells11040668. [PMID: 35203317 PMCID: PMC8869815 DOI: 10.3390/cells11040668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/31/2022] [Accepted: 02/10/2022] [Indexed: 11/23/2022] Open
Abstract
The machinery involved in cytotoxic T-cell activation requires three main characters: the major histocompatibility complex class I (MHC I) bound to the peptide (p), the T-cell receptor (TCR), and the CD3 complex, a multidimer interfaced with the intracellular side. The pMHC:TCR interaction has been largely studied by means of both experimental and computational models, giving a contribution in understanding the complexity of the TCR triggering. Nevertheless, a detailed study of the structural and dynamical characterization of the full complex (pMHC:TCR:CD3 complex) is still missing due to a lack of structural information of the CD3-chains arrangement around the TCR. Very recently, the determination of the TCR:CD3 complex structure by means of Cryo-EM technique has given a chance to build the entire system essential in the activation of T-cells, a fundamental mechanism in the adaptive immune response. Here, we present the first complete model of the pMHC interacting with the TCR:CD3 complex, built in a lipid environment. To describe the conformational behavior associated with the unbound and the bound states, all-atom Molecular Dynamics simulations were performed for the TCR:CD3 complex and for two pMHC:TCR:CD3 complex systems, bound to two different peptides. Our data point out that a conformational change affecting the TCR Constant β (Cβ) region occurs after the binding to the pMHC, revealing a key role of this region in the propagation of the signal. Moreover, we found that TCR reduces the flexibility of the MHC I binding groove, confirming our previous results.
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14
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Egan JR, Abu-Shah E, Dushek O, Elliott T, MacArthur BD. Fluctuations in T cell receptor and pMHC interactions regulate T cell activation. J R Soc Interface 2022; 19:20210589. [PMID: 35135295 PMCID: PMC8833104 DOI: 10.1098/rsif.2021.0589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Adaptive immune responses depend on interactions between T cell receptors (TCRs) and peptide major histocompatibility complex (pMHC) ligands located on the surface of T cells and antigen presenting cells (APCs), respectively. As TCRs and pMHCs are often only present at low copy numbers their interactions are inherently stochastic, yet the role of stochastic fluctuations on T cell function is unclear. Here, we introduce a minimal stochastic model of T cell activation that accounts for serial TCR-pMHC engagement, reversible TCR conformational change and TCR aggregation. Analysis of this model indicates that it is not the strength of binding between the T cell and the APC cell per se that elicits an immune response, but rather the information imparted to the T cell from the encounter, as assessed by the entropy rate of the TCR-pMHC binding dynamics. This view provides an information-theoretic interpretation of T cell activation that explains a range of experimental observations. Based on this analysis, we propose that effective T cell therapeutics may be enhanced by optimizing the inherent stochasticity of TCR-pMHC binding dynamics.
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Affiliation(s)
- Joseph R Egan
- Mathematical Sciences, Stem Cells and Regeneration, University of Southampton, Southampton SO17 1BJ, UK.,Institute for Life Sciences, Stem Cells and Regeneration, University of Southampton, Southampton SO17 1BJ, UK.,Centre for Cancer Immunology, University Hospital Southampton, Southampton SO16 6YD, UK.,Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Enas Abu-Shah
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.,Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Tim Elliott
- Institute for Life Sciences, Stem Cells and Regeneration, University of Southampton, Southampton SO17 1BJ, UK.,Centre for Cancer Immunology, University Hospital Southampton, Southampton SO16 6YD, UK.,Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Ben D MacArthur
- Mathematical Sciences, Stem Cells and Regeneration, University of Southampton, Southampton SO17 1BJ, UK.,Institute for Life Sciences, Stem Cells and Regeneration, University of Southampton, Southampton SO17 1BJ, UK.,Centre for Human Development, Stem Cells and Regeneration, University of Southampton, Southampton SO17 1BJ, UK.,Alan Turing Institute, London NW1 2DB, UK
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15
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Prakaash D, Cook GP, Acuto O, Kalli AC. Multi-scale simulations of the T cell receptor reveal its lipid interactions, dynamics and the arrangement of its cytoplasmic region. PLoS Comput Biol 2021; 17:e1009232. [PMID: 34280187 PMCID: PMC8321403 DOI: 10.1371/journal.pcbi.1009232] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 07/29/2021] [Accepted: 07/01/2021] [Indexed: 12/27/2022] Open
Abstract
The T cell receptor (TCR-CD3) initiates T cell activation by binding to peptides of Major Histocompatibility Complexes (pMHC). The TCR-CD3 topology is well understood but the arrangement and dynamics of its cytoplasmic tails remains unknown, limiting our grasp of the signalling mechanism. Here, we use molecular dynamics simulations and modelling to investigate the entire TCR-CD3 embedded in a model membrane. Our study demonstrates conformational changes in the extracellular and transmembrane domains, and the arrangement of the TCR-CD3 cytoplasmic tails. The cytoplasmic tails formed highly interlaced structures while some tyrosines within the immunoreceptor tyrosine-based activation motifs (ITAMs) penetrated the hydrophobic core of the membrane. Interactions between the cytoplasmic tails and phosphatidylinositol phosphate lipids in the inner membrane leaflet led to the formation of a distinct anionic lipid fingerprint around the TCR-CD3. These results increase our understanding of the TCR-CD3 dynamics and the importance of membrane lipids in regulating T cell activation.
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Affiliation(s)
- Dheeraj Prakaash
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
| | - Graham P. Cook
- Leeds Institute of Medical Research at St James’s, School of Medicine, University of Leeds, Leeds, United Kingdom
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Antreas C. Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
- Astbury Center for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom
- * E-mail:
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16
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Lanz AL, Masi G, Porciello N, Cohnen A, Cipria D, Prakaash D, Bálint Š, Raggiaschi R, Galgano D, Cole DK, Lepore M, Dushek O, Dustin ML, Sansom MSP, Kalli AC, Acuto O. Allosteric activation of T cell antigen receptor signaling by quaternary structure relaxation. Cell Rep 2021; 36:109375. [PMID: 34260912 PMCID: PMC8293630 DOI: 10.1016/j.celrep.2021.109375] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 05/05/2021] [Accepted: 06/18/2021] [Indexed: 01/05/2023] Open
Abstract
The mechanism of T cell antigen receptor (TCR-CD3) signaling remains elusive. Here, we identify mutations in the transmembrane region of TCRβ or CD3ζ that augment peptide T cell antigen receptor (pMHC)-induced signaling not explicable by enhanced ligand binding, lateral diffusion, clustering, or co-receptor function. Using a biochemical assay and molecular dynamics simulation, we demonstrate that the gain-of-function mutations loosen the interaction between TCRαβ and CD3ζ. Similar to the activating mutations, pMHC binding reduces TCRαβ cohesion with CD3ζ. This event occurs prior to CD3ζ phosphorylation and at 0°C. Moreover, we demonstrate that soluble monovalent pMHC alone induces signaling and reduces TCRαβ cohesion with CD3ζ in membrane-bound or solubilised TCR-CD3. Our data provide compelling evidence that pMHC binding suffices to activate allosteric changes propagating from TCRαβ to the CD3 subunits, reconfiguring interchain transmembrane region interactions. These dynamic modifications could change the arrangement of TCR-CD3 boundary lipids to license CD3ζ phosphorylation and initiate signal propagation. Mutations in TCRβ and CD3ζ TMRs that reduce their interaction augment signaling pMHC and anti-CD3 binding to TCR-CD3 induce similar quaternary structure relaxation Soluble monovalent pMHC alone signals and reduces TCRαβ cohesion with CD3ζ Allosteric changes in TCR-CD3 dynamics instigate T cell activation
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Affiliation(s)
- Anna-Lisa Lanz
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Giulia Masi
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Nicla Porciello
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - André Cohnen
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Deborah Cipria
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Dheeraj Prakaash
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK
| | - Štefan Bálint
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Roberto Raggiaschi
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Donatella Galgano
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - David K Cole
- Division Infection & Immunity, Cardiff University, Cardiff CF14 4XN, UK; Immunocore Ltd., Abingdon OX14 4RY, UK
| | | | - Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Michael L Dustin
- Kennedy Institute of Rheumatology, University of Oxford, Oxford OX3 7FY, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
| | - Antreas C Kalli
- Leeds Institute of Cardiovascular and Metabolic Medicine, University of Leeds, Leeds LS2 9JT, UK; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
| | - Oreste Acuto
- T-cell signalling laboratory, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK.
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17
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Bingöl EN, Serçinoğlu O, Ozbek P. Unraveling the Allosteric Communication Mechanisms in T-Cell Receptor-Peptide-Loaded Major Histocompatibility Complex Dynamics Using Molecular Dynamics Simulations: An Approach Based on Dynamic Cross Correlation Maps and Residue Interaction Energy Calculations. J Chem Inf Model 2021; 61:2444-2453. [PMID: 33930270 DOI: 10.1021/acs.jcim.1c00338] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antigen presentation by major histocompatibility complex (MHC) proteins to T-cell receptors (TCRs) plays a crucial role in triggering the adaptive immune response. Most of our knowledge on TCR-peptide-loaded major histocompatibility complex (pMHC) interaction stemmed from experiments yielding static structures, yet the dynamic aspects of this molecular interaction are equally important to understand the underlying molecular mechanisms and to develop treatment strategies against diseases such as cancer and autoimmune diseases. To this end, computational biophysics studies including all-atom molecular dynamics simulations have provided useful insights; however, we still lack a basic understanding of an overall allosteric mechanism that results in conformational changes in the TCR and subsequent T-cell activation. Previous hydrogen-deuterium exchange and nuclear magnetic resonance studies provided clues regarding these molecular mechanisms, including global rigidification and allosteric effects on the constant domain of TCRs away from the pMHC interaction site. Here, we show that molecular dynamics simulations can be used to identify how this overall rigidification may be related to the allosteric communication within TCRs upon pMHC interaction via essential dynamics and nonbonded residue-residue interaction energy analyses. The residues taking part in the rigidification effect are highlighted with an intricate analysis on residue interaction changes, which lead to a detailed outline of the complex formation event. Our results indicate that residues of the Cβ domain of TCRs show significant differences in their nonbonded interactions upon complex formation. Moreover, the dynamic cross correlations between these residues are also increased, in line with their nonbonded interaction energy changes. Altogether, our approach may be valuable for elucidating intramolecular allosteric changes in the TCR structure upon pMHC interaction in molecular dynamics simulations.
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Affiliation(s)
- Elif Naz Bingöl
- Department of Bioengineering, Institute of Pure and Applied Sciences, Marmara University, 34722 Istanbul, Turkey
| | - Onur Serçinoğlu
- Department of Bioengineering, Faculty of Engineering, Gebze Technical University, Kocaeli 41400, Turkey
| | - Pemra Ozbek
- Department of Bioengineering, Faculty of Engineering, Marmara University, Istanbul 34722, Turkey
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18
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Ma J, Ayres CM, Hellman LM, Devlin JR, Baker BM. Dynamic allostery controls the peptide sensitivity of the Ly49C natural killer receptor. J Biol Chem 2021; 296:100686. [PMID: 33891944 PMCID: PMC8138769 DOI: 10.1016/j.jbc.2021.100686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 04/14/2021] [Accepted: 04/19/2021] [Indexed: 11/30/2022] Open
Abstract
Using a variety of activating and inhibitory receptors, natural killer (NK) cells protect against disease by eliminating cells that have downregulated class I major histocompatibility complex (MHC) proteins, such as in response to cell transformation or viral infection. The inhibitory murine NK receptor Ly49C specifically recognizes the class I MHC protein H-2Kb. Unusual among NK receptors, Ly49C exhibits a peptide-dependent sensitivity to H-2Kb recognition, which has not been explained despite detailed structural studies. To gain further insight into Ly49C peptide sensitivity, we examined Ly49C recognition biochemically and through the lens of dynamic allostery. We found that the peptide sensitivity of Ly49C arises through small differences in H-2Kb-binding affinity. Although molecular dynamics simulations supported a role for peptide-dependent protein dynamics in producing these differences in binding affinity, calorimetric measurements indicated an enthalpically as opposed to entropically driven process. A quantitative linkage analysis showed that this emerges from peptide-dependent dynamic tuning of electrostatic interactions across the Ly49C–H-2Kb interface. We propose a model whereby different peptides alter the flexibility of H-2Kb, which in turn changes the strength of electrostatic interactions across the protein–protein interface. Our results provide a quantitative assessment of how peptides alter Ly49C-binding affinity, suggest the underlying mechanism, and demonstrate peptide-driven allostery at work in class I MHC proteins. Lastly, our model provides a solution for how dynamic allostery could impact binding of some, but not all, class I MHC partners depending on the structural and chemical composition of the interfaces.
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Affiliation(s)
- Jiaqi Ma
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA
| | - Cory M Ayres
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA
| | - Lance M Hellman
- Department of Physical and Life Sciences, Nevada State College, Henderson, Nevada, USA
| | - Jason R Devlin
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA
| | - Brian M Baker
- Department of Chemistry & Biochemistry and the Harper Cancer Research Institute, University of Notre Dame, Notre Dame, Indiana, USA.
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19
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Smith AR, Alonso JA, Ayres CM, Singh NK, Hellman LM, Baker BM. Structurally silent peptide anchor modifications allosterically modulate T cell recognition in a receptor-dependent manner. Proc Natl Acad Sci U S A 2021; 118:e2018125118. [PMID: 33468649 PMCID: PMC7848747 DOI: 10.1073/pnas.2018125118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Presentation of peptides by class I MHC proteins underlies T cell immune responses to pathogens and cancer. The association between peptide binding affinity and immunogenicity has led to the engineering of modified peptides with improved MHC binding, with the hope that these peptides would be useful for eliciting cross-reactive immune responses directed toward their weak binding, unmodified counterparts. Increasing evidence, however, indicates that T cell receptors (TCRs) can perceive such anchor-modified peptides differently than wild-type (WT) peptides, although the scope of discrimination is unclear. We show here that even modifications at primary anchors that have no discernible structural impact can lead to substantially stronger or weaker T cell recognition depending on the TCR. Surprisingly, the effect of peptide anchor modification can be sensed by a TCR at regions distant from the site of modification, indicating a through-protein mechanism in which the anchor residue serves as an allosteric modulator for TCR binding. Our findings emphasize caution in the use and interpretation of results from anchor-modified peptides and have implications for how anchor modifications are accounted for in other circumstances, such as predicting the immunogenicity of tumor neoantigens. Our data also highlight an important need to better understand the highly tunable dynamic nature of class I MHC proteins and the impact this has on various forms of immune recognition.
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MESH Headings
- Allosteric Regulation
- Binding Sites
- Cloning, Molecular
- Crystallography, X-Ray
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression
- Genetic Vectors/chemistry
- Genetic Vectors/metabolism
- HLA-A2 Antigen/chemistry
- HLA-A2 Antigen/genetics
- HLA-A2 Antigen/immunology
- Humans
- Jurkat Cells
- Kinetics
- Models, Molecular
- Peptides/chemistry
- Peptides/genetics
- Peptides/immunology
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Engineering
- Protein Interaction Domains and Motifs
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/immunology
- Th2 Cells/cytology
- Th2 Cells/immunology
- Thermodynamics
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Affiliation(s)
- Angela R Smith
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Jesus A Alonso
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Cory M Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Nishant K Singh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
| | - Lance M Hellman
- Department of Physical and Life Sciences, Nevada State College, Henderson, NV 89002
| | - Brian M Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556;
- Harper Cancer Research Institute, University of Notre Dame, Notre Dame, IN 46556
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20
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Pathan-Chhatbar S, Drechsler C, Richter K, Morath A, Wu W, OuYang B, Xu C, Schamel WW. Direct Regulation of the T Cell Antigen Receptor's Activity by Cholesterol. Front Cell Dev Biol 2021; 8:615996. [PMID: 33490080 PMCID: PMC7820176 DOI: 10.3389/fcell.2020.615996] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 12/09/2020] [Indexed: 11/14/2022] Open
Abstract
Biological membranes consist of hundreds of different lipids that together with the embedded transmembrane (TM) proteins organize themselves into small nanodomains. In addition to this function of lipids, TM regions of proteins bind to lipids in a very specific manner, but the function of these TM region-lipid interactions is mostly unknown. In this review, we focus on the role of plasma membrane cholesterol, which directly binds to the αβ T cell antigen receptor (TCR), and has at least two opposing functions in αβ TCR activation. On the one hand, cholesterol binding to the TM domain of the TCRβ subunit keeps the TCR in an inactive, non-signaling conformation by stabilizing this conformation. This assures that the αβ T cell remains quiescent in the absence of antigenic peptide-MHC (the TCR's ligand) and decreases the sensitivity of the T cell toward stimulation. On the other hand, cholesterol binding to TCRβ leads to an increased formation of TCR nanoclusters, increasing the avidity of the TCRs toward the antigen, thus increasing the sensitivity of the αβ T cell. In mouse models, pharmacological increase of the cholesterol concentration in T cells caused an increase in TCR clustering, and thereby enhanced anti-tumor responses. In contrast, the γδ TCR does not bind to cholesterol and might be regulated in a different manner. The goal of this review is to put these seemingly controversial findings on the impact of cholesterol on the αβ TCR into perspective.
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Affiliation(s)
- Salma Pathan-Chhatbar
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany.,Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Carina Drechsler
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany.,Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Kirsten Richter
- Immunology, Infectious Diseases and Ophthalmology Disease Translational Area, Roche Innovation Center Basel, Basel, Switzerland
| | - Anna Morath
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany.,Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
| | - Wei Wu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Bo OuYang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Chenqi Xu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Wolfgang W Schamel
- Centre for Biological Signalling Studies and Centre for Integrative Biological Signalling Studies, University Freiburg, Freiburg, Germany.,Department of Immunology, Faculty of Biology, University of Freiburg, Freiburg, Germany.,Centre for Chronic Immunodeficiency (CCI), University of Freiburg, Freiburg, Germany
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21
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He Y, Agnihotri P, Rangarajan S, Chen Y, Kerzic MC, Ma B, Nussinov R, Mariuzza RA, Orban J. Peptide-MHC Binding Reveals Conserved Allosteric Sites in MHC Class I- and Class II-Restricted T Cell Receptors (TCRs). J Mol Biol 2020; 432:166697. [PMID: 33157083 PMCID: PMC8356565 DOI: 10.1016/j.jmb.2020.10.031] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 09/29/2020] [Accepted: 10/27/2020] [Indexed: 12/31/2022]
Abstract
T cells are vital for adaptive immune responses that protect against pathogens and cancers. The T cell receptor (TCR)-CD3 complex comprises a diverse αβ TCR heterodimer in noncovalent association with three invariant CD3 dimers. The TCR is responsible for recognizing antigenic peptides bound to MHC molecules (pMHC), while the CD3 dimers relay activation signals to the T cell. However, the mechanisms by which TCR engagement by pMHC is transmitted to CD3 remain mysterious, although there is growing evidence that mechanosensing and allostery both play a role. Here, we carried out NMR analysis of a human autoimmune TCR (MS2-3C8) that recognizes a self-peptide from myelin basic protein presented by the MHC class II molecule HLA-DR4. We observed pMHC-induced NMR signal perturbations in MS2-3C8 that indicate long-range effects on TCR β chain conformation and dynamics. Our results demonstrate that, in addition to expected changes in the NMR resonances of pMHC-contacting residues, perturbations extend to the Vβ/Vα, Vβ/Cβ, and Cβ/Cα interfacial regions. Moreover, the pattern of long-range perturbations is similar to that detected previously in the β chains of two MHC class I-restricted TCRs, thereby revealing a common allosteric pathway among three unrelated TCRs. Molecular dynamics (MD) simulations predict similar pMHC-induced effects. Taken together, our results demonstrate that pMHC binding induces long-range allosteric changes in the TCR β chain at conserved sites in both representative MHC class I- and class II-restricted TCRs, and that these sites may play a role in the transmission of signaling information.
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Affiliation(s)
- Yanan He
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Pragati Agnihotri
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Sneha Rangarajan
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Yihong Chen
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Melissa C Kerzic
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Buyong Ma
- Engineering Research Center of Cell & Therapeutic Antibody, MOE, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, China; Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, USA
| | - Roy A Mariuzza
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA.
| | - John Orban
- W.M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD 20850, USA; Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA.
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22
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Kristi N, Gafur A, Kong L, Ma X, Ye Z, Wang G. Atomic Force Microscopy in Mechanoimmunology Analysis: A New Perspective for Cancer Immunotherapy. Biotechnol J 2020; 15:e1900559. [PMID: 32240578 DOI: 10.1002/biot.201900559] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 03/08/2020] [Indexed: 01/05/2023]
Abstract
Immunotherapy has remarkable success outcomes against hematological malignancies with high rates of complete remission. To date, many studies have been conducted to increase its effectiveness in other types of cancer. However, it still yields unsatisfying results in solid tumor therapy. This limitation is partly attributed to the lack of understanding of how immunotherapy works in cancer from other perspectives. The traditional studies focus on the biological and chemical perspectives to determine which molecular substrates are involved in the immune system that can eradicate cancer cells. In the last decades, accumulating evidence has shown that physical properties also play important roles in the immune system to combat cancer, which is studied in mechanoimmunology. Mechanoimmunology analysis requires special tools; and herein, atomic force microscopy (AFM) appears as a versatile tool to determine and quantify the mechanical properties of a sample in nanometer precisions. Owing to its multifunctional capabilities, AFM can be used to explore immune system function from the physical perspective. This review paper explains the mechanoimmunology of how immune systems work through AFM, which includes mechanosignaling, mechanosensing, and mechanotransduction, with the aim to deepen the understanding of the mechanistic role of immunotherapy for further development in cancer treatment.
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Affiliation(s)
- Natalia Kristi
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing, 400030, China
| | - Alidha Gafur
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing, 400030, China
| | - Lingwen Kong
- Department of Cardiothoracic Surgery, Central Hospital of Chongqing University, Chongqing Emergency Medical Center, Chongqing, 400014, P. R. China
| | - Xinshuang Ma
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing, 400030, China
| | - Zhiyi Ye
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing, 400030, China
| | - Guixue Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, State and Local Joint Engineering Laboratory for Vascular Implants, College of Bioengineering, Chongqing, 400030, China
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23
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High throughput pMHC-I tetramer library production using chaperone-mediated peptide exchange. Nat Commun 2020; 11:1909. [PMID: 32312993 PMCID: PMC7170893 DOI: 10.1038/s41467-020-15710-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 03/23/2020] [Indexed: 12/31/2022] Open
Abstract
Peptide exchange technologies are essential for the generation of pMHC-multimer libraries used to probe diverse, polyclonal TCR repertoires in various settings. Here, using the molecular chaperone TAPBPR, we develop a robust method for the capture of stable, empty MHC-I molecules comprising murine H2 and human HLA alleles, which can be readily tetramerized and loaded with peptides of choice in a high-throughput manner. Alternatively, catalytic amounts of TAPBPR can be used to exchange placeholder peptides with high affinity peptides of interest. Using the same system, we describe high throughput assays to validate binding of multiple candidate peptides on empty MHC-I/TAPBPR complexes. Combined with tetramer-barcoding via a multi-modal cellular indexing technology, ECCITE-seq, our approach allows a combined analysis of TCR repertoires and other T cell transcription profiles together with their cognate antigen specificities in a single experiment. The new approach allows TCR/pMHC interactions to be interrogated easily at large scale. Peptide-MHC (pMHC) tetramers are important tools for probing T cell repertoire and adaptive immune responses. Here the authors use a molecular chaperone, TAPBPR, to develop a high-throughput, multiplexible platform for pMHC tetramer generation to facilitate simultaneous assessments of T cell repertoire/antigen specificity and transcriptome.
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24
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Alba J, Di Rienzo L, Milanetti E, Acuto O, D’Abramo M. Molecular Dynamics Simulations Reveal Canonical Conformations in Different pMHC/TCR Interactions. Cells 2020; 9:E942. [PMID: 32290289 PMCID: PMC7226950 DOI: 10.3390/cells9040942] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 01/14/2023] Open
Abstract
The major defense system against microbial pathogens in vertebrates is the adaptive immune response and represents an effective mechanism in cancer surveillance. T cells represent an essential component of this complex system. They can recognize myriads of antigens as short peptides (p) originated from the intracellular degradation of foreign proteins presented by major histocompatibility complex (MHC) proteins. The clonotypic T-cell antigen receptor (TCR) is specialized in recognizing pMHC and triggering T cells immune response. It is still unclear how TCR engagement to pMHC is translated into the intracellular signal that initiates T-cell immune response. Some work has suggested the possibility that pMHC binding induces in the TCR conformational changes transmitted to its companion CD3 subunits that govern signaling. The conformational changes would promote phosphorylation of the CD3 complex ζ chain that initiates signal propagation intracellularly. Here, we used all-atom molecular dynamics simulations (MDs) of 500 ns to analyze the conformational behavior of three TCRs (1G4, ILA1 and ILA1α1β1) interacting with the same MHC class I (HLA-A*02:01) bound to different peptides, and modelled in the presence of a lipid bilayer. Our data suggest a correlation between the conformations explored by the β-chain constant regions and the T-cell response experimentally determined. In particular, independently by the TCR type involved in the interaction, the TCR activation seems to be linked to a specific zone of the conformational space explored by the β-chain constant region. Moreover, TCR ligation restricts the conformational space the MHC class I groove.
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Affiliation(s)
- Josephine Alba
- Department of Chemistry, University of Rome Sapienza, P.le A.Moro 5-00185 Rome, Italy
| | - Lorenzo Di Rienzo
- Department of Physics, University of Rome Sapienza, 5-00185 Rome Italy; (L.D.R.); (E.M.)
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 000161 Rome, Italy
| | - Edoardo Milanetti
- Department of Physics, University of Rome Sapienza, 5-00185 Rome Italy; (L.D.R.); (E.M.)
- Center for Life Nano Science@Sapienza, Istituto Italiano di Tecnologia, 000161 Rome, Italy
| | - Oreste Acuto
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK;
| | - Marco D’Abramo
- Department of Chemistry, University of Rome Sapienza, P.le A.Moro 5-00185 Rome, Italy
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25
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Singh NK, Abualrous ET, Ayres CM, Noé F, Gowthaman R, Pierce BG, Baker BM. Geometrical characterization of T cell receptor binding modes reveals class-specific binding to maximize access to antigen. Proteins 2020; 88:503-513. [PMID: 31589793 PMCID: PMC6982585 DOI: 10.1002/prot.25829] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2019] [Revised: 08/08/2019] [Accepted: 09/17/2019] [Indexed: 11/11/2022]
Abstract
Recognition of antigenic peptides bound to major histocompatibility complex (MHC) proteins by αβ T cell receptors (TCRs) is a hallmark of T cell mediated immunity. Recent data suggest that variations in TCR binding geometry may influence T cell signaling, which could help explain outliers in relationships between physical parameters such as TCR-pMHC binding affinity and T cell function. Traditionally, TCR binding geometry has been described with simple descriptors such as the crossing angle, which quantifies what has become known as the TCR's diagonal binding mode. However, these descriptors often fail to reveal distinctions in binding geometry that are apparent through visual inspection. To provide a better framework for relating TCR structure to T cell function, we developed a comprehensive system for quantifying the geometries of how TCRs bind peptide/MHC complexes. We show that our system can discern differences not clearly revealed by more common methods. As an example of its potential to impact biology, we used it to reveal differences in how TCRs bind class I and class II peptide/MHC complexes, which we show allow the TCR to maximize access to and "read out" the peptide antigen. We anticipate our system will be of use in not only exploring these and other details of TCR-peptide/MHC binding interactions, but also addressing questions about how TCR binding geometry relates to T cell function, as well as modeling structural properties of class I and class II TCR-peptide/MHC complexes from sequence information. The system is available at https://tcr3d.ibbr.umd.edu/tcr_com or for download as a script.
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MESH Headings
- Binding Sites
- Crystallography, X-Ray
- Histocompatibility Antigens Class I/chemistry
- Histocompatibility Antigens Class I/immunology
- Histocompatibility Antigens Class I/metabolism
- Histocompatibility Antigens Class II/chemistry
- Histocompatibility Antigens Class II/immunology
- Histocompatibility Antigens Class II/metabolism
- Humans
- Models, Molecular
- Principal Component Analysis
- Protein Binding
- Protein Conformation, alpha-Helical
- Protein Conformation, beta-Strand
- Protein Interaction Domains and Motifs
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- T-Lymphocytes/chemistry
- T-Lymphocytes/immunology
- T-Lymphocytes/metabolism
- Thermodynamics
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Affiliation(s)
- Nishant K. Singh
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
- Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Esam T. Abualrous
- Molecular Biology Group, Institute for Mathematics, Freie Universität Berlin, Berlin, Germany
| | - Cory M. Ayres
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
- Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
| | - Frank Noé
- Molecular Biology Group, Institute for Mathematics, Freie Universität Berlin, Berlin, Germany
| | - Ragul Gowthaman
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, United States
| | - Brian G. Pierce
- University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, MD, United States
| | - Brian M. Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, United States
- Harper Cancer Research Institute, University of Notre Dame, South Bend, IN, United States
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26
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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: 47] [Impact Index Per Article: 11.8] [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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27
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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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28
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Trowitzsch S, Tampé R. Multifunctional Chaperone and Quality Control Complexes in Adaptive Immunity. Annu Rev Biophys 2020; 49:135-161. [PMID: 32004089 DOI: 10.1146/annurev-biophys-121219-081643] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The fundamental process of adaptive immunity relies on the differentiation of self from nonself. Nucleated cells are continuously monitored by effector cells of the immune system, which police the peptide status presented via cell surface molecules. Recent integrative structural approaches have provided insights toward our understanding of how sophisticated cellular machineries shape such hierarchical immune surveillance. Biophysical and structural achievements were invaluable for defining the interconnection of many key factors during antigen processing and presentation, and helped to solve several conundrums that persisted for many years. In this review, we illuminate the numerous quality control machineries involved in different steps during the maturation of major histocompatibility complex class I (MHC I) proteins, from their synthesis in the endoplasmic reticulum to folding and trafficking via the secretory pathway, optimization of antigenic cargo, final release to the cell surface, and engagement with their cognate receptors on cytotoxic T lymphocytes.
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Affiliation(s)
- Simon Trowitzsch
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; ,
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; ,
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29
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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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30
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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: 48] [Impact Index Per Article: 9.6] [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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31
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Molecular determinants of chaperone interactions on MHC-I for folding and antigen repertoire selection. Proc Natl Acad Sci U S A 2019; 116:25602-25613. [PMID: 31796585 PMCID: PMC6926029 DOI: 10.1073/pnas.1915562116] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The interplay between a highly polymorphic set of MHC-I alleles and molecular chaperones shapes the repertoire of peptide antigens displayed on the cell surface for T cell surveillance. Here, we demonstrate that the molecular chaperone TAP-binding protein related (TAPBPR) associates with a broad range of partially folded MHC-I species inside the cell. Bimolecular fluorescence complementation and deep mutational scanning reveal that TAPBPR recognition is polarized toward the α2 domain of the peptide-binding groove, and depends on the formation of a conserved MHC-I disulfide epitope in the α2 domain. Conversely, thermodynamic measurements of TAPBPR binding for a representative set of properly conformed, peptide-loaded molecules suggest a narrower MHC-I specificity range. Using solution NMR, we find that the extent of dynamics at "hotspot" surfaces confers TAPBPR recognition of a sparsely populated MHC-I state attained through a global conformational change. Consistently, restriction of MHC-I groove plasticity through the introduction of a disulfide bond between the α1/α2 helices abrogates TAPBPR binding, both in solution and on a cellular membrane, while intracellular binding is tolerant of many destabilizing MHC-I substitutions. Our data support parallel TAPBPR functions of 1) chaperoning unstable MHC-I molecules with broad allele-specificity at early stages of their folding process, and 2) editing the peptide cargo of properly conformed MHC-I molecules en route to the surface, which demonstrates a narrower specificity. Our results suggest that TAPBPR exploits localized structural adaptations, both near and distant to the peptide-binding groove, to selectively recognize discrete conformational states sampled by MHC-I alleles, toward editing the repertoire of displayed antigens.
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32
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Sádio F, Stadlmayr G, Stadlbauer K, Gräf M, Scharrer A, Rüker F, Wozniak-Knopp G. Stabilization of soluble high-affinity T-cell receptor with de novo disulfide bonds. FEBS Lett 2019; 594:477-490. [PMID: 31552676 PMCID: PMC7027902 DOI: 10.1002/1873-3468.13616] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 09/04/2019] [Accepted: 09/17/2019] [Indexed: 12/12/2022]
Abstract
Soluble T‐cell receptors (TCRs) have recently gained visibility as target‐recognition units of anticancer immunotherapeutic agents. Here, we improved the thermal stability of the well‐expressed high‐affinity A6 TCR by introducing pairs of cysteines in the invariable parts of the α‐ and β‐chain. A mutant with a novel intradomain disulfide bond in each chain also tested superior to the wild‐type in the accelerated stability assay. Binding of the mutant to the soluble cognate peptide (cp)–MHC and to the peptide‐loaded T2 cell line was equal to the wild‐type A6 TCR. The same stabilization motif worked efficiently in TCRs with different specificities, such as DMF5 and 1G4. Altogether, the biophysical properties of the soluble TCR molecule could be improved, without affecting its expression level and antigen‐binding specificity.
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Affiliation(s)
- Flávio Sádio
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Gerhard Stadlmayr
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Katharina Stadlbauer
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Maximilian Gräf
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Agnes Scharrer
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Florian Rüker
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Gordana Wozniak-Knopp
- Christian Doppler Laboratory for Innovative Immunotherapeutics, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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TCR-pMHC bond conformation controls TCR ligand discrimination. Cell Mol Immunol 2019; 17:203-217. [PMID: 31530899 PMCID: PMC7052167 DOI: 10.1038/s41423-019-0273-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 08/07/2019] [Indexed: 11/15/2022] Open
Abstract
A major unanswered question is how a TCR discriminates between foreign and self-peptides presented on the APC surface. Here, we used in situ fluorescence resonance energy transfer (FRET) to measure the distances of single TCR–pMHC bonds and the conformations of individual TCR–CD3ζ receptors at the membranes of live primary T cells. We found that a TCR discriminates between closely related peptides by forming single TCR–pMHC bonds with different conformations, and the most potent pMHC forms the shortest bond. The bond conformation is an intrinsic property that is independent of the binding affinity and kinetics, TCR microcluster formation, and CD4 binding. The bond conformation dictates the degree of CD3ζ dissociation from the inner leaflet of the plasma membrane via a positive calcium signaling feedback loop to precisely control the accessibility of CD3ζ ITAMs for phosphorylation. Our data revealed the mechanism by which a TCR deciphers the structural differences among peptides via the TCR–pMHC bond conformation.
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Knapp B, van der Merwe PA, Dushek O, Deane CM. MHC binding affects the dynamics of different T-cell receptors in different ways. PLoS Comput Biol 2019; 15:e1007338. [PMID: 31498801 PMCID: PMC6752857 DOI: 10.1371/journal.pcbi.1007338] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 09/19/2019] [Accepted: 08/20/2019] [Indexed: 12/13/2022] Open
Abstract
T cells use their T-cell receptors (TCRs) to scan other cells for antigenic peptides presented by MHC molecules (pMHC). If a TCR encounters a pMHC, it can trigger a signalling pathway that could lead to the activation of the T cell and the initiation of an immune response. It is currently not clear how the binding of pMHC to the TCR initiates signalling within the T cell. One hypothesis is that conformational changes in the TCR lead to further downstream signalling. Here we investigate four different TCRs in their free state as well as in their pMHC bound state using large scale molecular simulations totalling 26 000 ns. We find that the dynamical features within TCRs differ significantly between unbound TCR and TCR/pMHC simulations. However, apart from expected results such as reduced solvent accessibility and flexibility of the interface residues, these features are not conserved among different TCR types. The presence of a pMHC alone is not sufficient to cause cross-TCR-conserved dynamical features within a TCR. Our results argue against models of TCR triggering involving conserved allosteric conformational changes. The interaction between T-cells and other cells is one of the most important interactions in the human immune system. If T-cells are not triggered major parts of the immune system cannot be activated or are not working effectively. Despite many years of research the exact mechanism of how a T-cell is initially triggered is not clear. One hypothesis is that conformational changes within the T-cell receptor (TCR) can cause further downstream signalling within the T-cell. In this study we computationally investigate the dynamics of four different TCRs in their free and bound configuration. Our large scale simulations show that all four TCRs react to binding in different ways. In some TCRs mainly the areas close to the binding region are affected while in other TCRs areas further apart from the binding region are also affected. Our results argue against a conserved structural activation mechanism across different types of TCRs.
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Affiliation(s)
- Bernhard Knapp
- Department of Basic Sciences, International University of Catalonia, Barcelona, Spain
- Department of Statistics, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | | | - Omer Dushek
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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Structural basis of assembly of the human T cell receptor-CD3 complex. Nature 2019; 573:546-552. [PMID: 31461748 DOI: 10.1038/s41586-019-1537-0] [Citation(s) in RCA: 174] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/19/2019] [Indexed: 01/10/2023]
Abstract
The αβ T cell receptor (TCR), in association with the CD3γε-CD3δε-CD3ζζ signalling hexamer, is the primary determinant of T cell development and activation, and of immune responses to foreign antigens. The mechanism of assembly of the TCR-CD3 complex remains unknown. Here we report a cryo-electron microscopy structure of human TCRαβ in complex with the CD3 hexamer at 3.7 Å resolution. The structure contains the complete extracellular domains and all the transmembrane helices of TCR-CD3. The octameric TCR-CD3 complex is assembled with 1:1:1:1 stoichiometry of TCRαβ:CD3γε:CD3δε:CD3ζζ. Assembly of the extracellular domains of TCR-CD3 is mediated by the constant domains and connecting peptides of TCRαβ that pack against CD3γε-CD3δε, forming a trimer-like structure proximal to the plasma membrane. The transmembrane segment of the CD3 complex adopts a barrel-like structure formed by interaction of the two transmembrane helices of CD3ζζ with those of CD3γε and CD3δε. Insertion of the transmembrane helices of TCRαβ into the barrel-like structure via both hydrophobic and ionic interactions results in transmembrane assembly of the TCR-CD3 complex. Together, our data reveal the structural basis for TCR-CD3 complex assembly, providing clues to TCR triggering and a foundation for rational design of immunotherapies that target the complex.
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36
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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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37
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38
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Dominguez JL, Knapp B. How peptide/MHC presence affects the dynamics of the LC13 T-cell receptor. Sci Rep 2019; 9:2638. [PMID: 30804417 PMCID: PMC6389892 DOI: 10.1038/s41598-019-38788-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/19/2018] [Indexed: 12/04/2022] Open
Abstract
The interaction between T-cell receptors (TCRs) of T-cells and potentially immunogenic peptides presented by MHCs of antigen presenting cells is one of the most important mechanisms of the adaptive human immune system. A large number of structural simulations of the TCR/peptide/MHC system have been carried out. However, to date no study has investigated the differences of the dynamics between free TCRs and pMHC bound TCRs on a large scale. Here we present a study totalling 37 100 ns investigating the LC13 TCR in its free form as well as in complex with HLA-B*08:01 and different peptides. Our results show that the dynamics of the bound and unbound LC13 TCR differ significantly. This is reflected in (a) expected results such as an increased flexibility and increased solvent accessible surface of the CDRs of unbound TCR simulations but also in (b) less expected results such as lower CDR distances and compactness as well as alteration in the hydrogen bond network around CDR3α of unbound TCR simulations. Our study further emphasises the structural flexibility of TCRs and confirms the importance of the CDR3 loops for the adoption to MHC.
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Affiliation(s)
- Jose Luis Dominguez
- Department of Basic Sciences, International University of Catalonia, Barcelona, Spain
| | - Bernhard Knapp
- Department of Basic Sciences, International University of Catalonia, Barcelona, Spain.
- Department of Statistics, Protein Informatics Group, University of Oxford, Oxford, UK.
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39
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Wu P, Zhang T, Liu B, Fei P, Cui L, Qin R, Zhu H, Yao D, Martinez RJ, Hu W, An C, Zhang Y, Liu J, Shi J, Fan J, Yin W, Sun J, Zhou C, Zeng X, Xu C, Wang J, Evavold BD, Zhu C, Chen W, Lou J. Mechano-regulation of Peptide-MHC Class I Conformations Determines TCR Antigen Recognition. Mol Cell 2019; 73:1015-1027.e7. [PMID: 30711376 PMCID: PMC6408234 DOI: 10.1016/j.molcel.2018.12.018] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/27/2018] [Accepted: 12/20/2018] [Indexed: 01/08/2023]
Abstract
TCRs recognize cognate pMHCs to initiate T cell signaling and adaptive immunity. Mechanical force strengthens TCR-pMHC interactions to elicit agonist-specific catch bonds to trigger TCR signaling, but the underlying dynamic structural mechanism is unclear. We combined steered molecular dynamics (SMD) simulation, single-molecule biophysical approaches, and functional assays to collectively demonstrate that mechanical force induces conformational changes in pMHCs to enhance pre-existing contacts and activates new interactions at the TCR-pMHC binding interface to resist bond dissociation under force, resulting in TCR-pMHC catch bonds and T cell activation. Intriguingly, cancer-associated somatic mutations in HLA-A2 that may restrict these conformational changes suppressed TCR-pMHC catch bonds. Structural analysis also indicated that HLA polymorphism might alter the equilibrium of these conformational changes. Our findings not only reveal critical roles of force-induced conformational changes in pMHCs for activating TCR-pMHC catch bonds but also have implications for T cell-based immunotherapy.
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Affiliation(s)
- Peng Wu
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Tongtong Zhang
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Baoyu Liu
- Coulter Department of Biomedical Engineering, Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA; Department of Microbiology and Immunology, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Panyu Fei
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310058, China
| | - Lei Cui
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Rui Qin
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Huaying Zhu
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Danmei Yao
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Ryan J Martinez
- Department of Microbiology and Immunology, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Wei Hu
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Chenyi An
- School of Mechanical Engineering, Zhejiang University, Hangzhou 310058, China
| | - Yong Zhang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Junwei Liu
- Key Laboratory for Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310058, China
| | - Jiawei Shi
- Key Laboratory for Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310058, China
| | - Juan Fan
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Weiwei Yin
- Key Laboratory for Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310058, China
| | - Jie Sun
- Department of Cell Biology and Bone Marrow Transplantation Center of the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Chun Zhou
- School of Public Health and Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xun Zeng
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, and First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Chenqi Xu
- State Key Laboratory of Molecular Biology, Chinese Academy Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of the Chinese Academy of Sciences, Shanghai 200031, China
| | - Jianan Wang
- Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Brian D Evavold
- Department of Microbiology and Immunology, School of Medicine, Emory University, Atlanta, GA 30322, USA
| | - Cheng Zhu
- Coulter Department of Biomedical Engineering, Woodruff School of Mechanical Engineering, Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Wei Chen
- Department of Neurobiology, Institute of Neuroscience, and Department of Cardiology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China; Key Laboratory for Biomedical Engineering of the Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou 310058, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, State Key Laboratory for Modern Optical Instrumentation, Zhejiang University, Hangzhou 310058, China.
| | - Jizhong Lou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of the Chinese Academy of Sciences, Beijing 100049, China.
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40
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Jiang J, Natarajan K, Margulies DH. MHC Molecules, T cell Receptors, Natural Killer Cell Receptors, and Viral Immunoevasins-Key Elements of Adaptive and Innate Immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1172:21-62. [PMID: 31628650 DOI: 10.1007/978-981-13-9367-9_2] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Molecules encoded by the Major Histocompatibility Complex (MHC) bind self or foreign peptides and display these at the cell surface for recognition by receptors on T lymphocytes (designated T cell receptors-TCR) or on natural killer (NK) cells. These ligand/receptor interactions govern T cell and NK cell development as well as activation of T memory and effector cells. Such cells participate in immunological processes that regulate immunity to various pathogens, resistance and susceptibility to cancer, and autoimmunity. The past few decades have witnessed the accumulation of a huge knowledge base of the molecular structures of MHC molecules bound to numerous peptides, of TCRs with specificity for many different peptide/MHC (pMHC) complexes, of NK cell receptors (NKR), of MHC-like viral immunoevasins, and of pMHC/TCR and pMHC/NKR complexes. This chapter reviews the structural principles that govern peptide/MHC (pMHC), pMHC/TCR, and pMHC/NKR interactions, for both MHC class I (MHC-I) and MHC class II (MHC-II) molecules. In addition, we discuss the structures of several representative MHC-like molecules. These include host molecules that have distinct biological functions, as well as virus-encoded molecules that contribute to the evasion of the immune response.
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Affiliation(s)
- Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11D07, 10 Center Drive, Bethesda, MD, 20892-1892, USA.
| | - Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11D07, 10 Center Drive, Bethesda, MD, 20892-1892, USA
| | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bldg. 10, Room 11D12, 10 Center Drive, Bethesda, MD, 20892-1892, USA
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41
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Abstract
Major histocompatibility class I (MHC-I) molecules bind peptides derived from cellular synthesis and display them at the cell surface for recognition by receptors on T lymphocytes (TCR) or natural killer (NK) cells. Such recognition provides a crucial step in autoimmunity, identification of bacterial and viral pathogens, and anti-tumor responses. Understanding the mechanism by which such antigenic peptides in the ER are loaded and exchanged for higher affinity peptides onto MHC molecules has recently been clarified by cryo-EM and X-ray studies of the multimolecular peptide loading complex (PLC) and a unimolecular tapasin-like chaperone designated TAPBPR. Insights from these structural studies and complementary solution NMR experiments provide a basis for understanding mechanisms related to immune antigen presentation.
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42
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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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43
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Rangarajan S, He Y, Chen Y, Kerzic MC, Ma B, Gowthaman R, Pierce BG, Nussinov R, Mariuzza RA, Orban J. Peptide-MHC (pMHC) binding to a human antiviral T cell receptor induces long-range allosteric communication between pMHC- and CD3-binding sites. J Biol Chem 2018; 293:15991-16005. [PMID: 30135211 PMCID: PMC6187629 DOI: 10.1074/jbc.ra118.003832] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 08/21/2018] [Indexed: 12/17/2022] Open
Abstract
T cells generate adaptive immune responses mediated by the T cell receptor (TCR)-CD3 complex comprising an αβ TCR heterodimer noncovalently associated with three CD3 dimers. In early T cell activation, αβ TCR engagement by peptide-major histocompatibility complex (pMHC) is first communicated to the CD3 signaling apparatus of the TCR-CD3 complex, but the underlying mechanism is incompletely understood. It is possible that pMHC binding induces allosteric changes in TCR conformation or dynamics that are then relayed to CD3. Here, we carried out NMR analysis and molecular dynamics (MD) simulations of both the α and β chains of a human antiviral TCR (A6) that recognizes the Tax antigen from human T cell lymphotropic virus-1 bound to the MHC class I molecule HLA-A2. We observed pMHC-induced NMR signal perturbations in the TCR variable (V) domains that propagated to three distinct sites in the constant (C) domains: 1) the Cβ FG loop projecting from the Vβ/Cβ interface; 2) a cluster of Cβ residues near the Cβ αA helix, a region involved in interactions with CD3; and 3) the Cα AB loop at the membrane-proximal base of the TCR. A biological role for each of these allosteric sites is supported by previous mutational and functional studies of TCR signaling. Moreover, the pattern of long-range, ligand-induced changes in TCR A6 revealed by NMR was broadly similar to that predicted by the MD simulations. We propose that the unique structure of the TCR β chain enables allosteric communication between the TCR-binding sites for pMHC and CD3.
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MESH Headings
- Allosteric Regulation
- Animals
- Binding Sites
- Gene Products, tax/chemistry
- Gene Products, tax/metabolism
- HLA-A2 Antigen/chemistry
- HLA-A2 Antigen/metabolism
- Human T-lymphotropic virus 1/chemistry
- Humans
- Mice
- Molecular Dynamics Simulation
- Protein Binding
- Protein Conformation
- Receptor-CD3 Complex, Antigen, T-Cell/chemistry
- Receptor-CD3 Complex, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
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Affiliation(s)
- Sneha Rangarajan
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
- the Departments of Cell Biology and Molecular Genetics and
| | - Yanan He
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
- Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, and
| | - Yihong Chen
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Melissa C Kerzic
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
| | - Buyong Ma
- the Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702
| | - Ragul Gowthaman
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
- the Departments of Cell Biology and Molecular Genetics and
| | - Brian G Pierce
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850
- the Departments of Cell Biology and Molecular Genetics and
| | - Ruth Nussinov
- the Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702
| | - Roy A Mariuzza
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850,
- the Departments of Cell Biology and Molecular Genetics and
| | - John Orban
- From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850,
- Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, and
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44
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Sibener LV, Fernandes RA, Kolawole EM, Carbone CB, Liu F, McAffee D, Birnbaum ME, Yang X, Su LF, Yu W, Dong S, Gee MH, Jude KM, Davis MM, Groves JT, Goddard WA, Heath JR, Evavold BD, Vale RD, Garcia KC. Isolation of a Structural Mechanism for Uncoupling T Cell Receptor Signaling from Peptide-MHC Binding. Cell 2018; 174:672-687.e27. [PMID: 30053426 PMCID: PMC6140336 DOI: 10.1016/j.cell.2018.06.017] [Citation(s) in RCA: 187] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 03/13/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
TCR-signaling strength generally correlates with peptide-MHC binding affinity; however, exceptions exist. We find high-affinity, yet non-stimulatory, interactions occur with high frequency in the human T cell repertoire. Here, we studied human TCRs that are refractory to activation by pMHC ligands despite robust binding. Analysis of 3D affinity, 2D dwell time, and crystal structures of stimulatory versus non-stimulatory TCR-pMHC interactions failed to account for their different signaling outcomes. Using yeast pMHC display, we identified peptide agonists of a formerly non-responsive TCR. Single-molecule force measurements demonstrated the emergence of catch bonds in the activating TCR-pMHC interactions, correlating with exclusion of CD45 from the TCR-APC contact site. Molecular dynamics simulations of TCR-pMHC disengagement distinguished agonist from non-agonist ligands based on the acquisition of catch bonds within the TCR-pMHC interface. The isolation of catch bonds as a parameter mediating the coupling of TCR binding and signaling has important implications for TCR and antigen engineering for immunotherapy.
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Affiliation(s)
- Leah V Sibener
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Immunology Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ricardo A Fernandes
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elizabeth M Kolawole
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Catherine B Carbone
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Fan Liu
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA; Institute for Systems Biology, Seattle, WA 98109, USA
| | - Darren McAffee
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Michael E Birnbaum
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Immunology Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Xinbo Yang
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Laura F Su
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Wong Yu
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shen Dong
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marvin H Gee
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Immunology Graduate Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mark M Davis
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jay T Groves
- Department of Chemistry, University of California, Berkeley, Berkeley, CA 94720, USA
| | - William A Goddard
- Department of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Materials and Process Simulation Center, California Institute of Technology, Pasadena, CA 91125, USA
| | - James R Heath
- Institute for Systems Biology, Seattle, WA 98109, USA
| | - Brian D Evavold
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Ronald D Vale
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - K Christopher Garcia
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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Natarajan K, Jiang J, May NA, Mage MG, Boyd LF, McShan AC, Sgourakis NG, Bax A, Margulies DH. The Role of Molecular Flexibility in Antigen Presentation and T Cell Receptor-Mediated Signaling. Front Immunol 2018; 9:1657. [PMID: 30065727 PMCID: PMC6056622 DOI: 10.3389/fimmu.2018.01657] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 07/04/2018] [Indexed: 01/20/2023] Open
Abstract
Antigen presentation is a cellular process that involves a number of steps, beginning with the production of peptides by proteolysis or aberrant synthesis and the delivery of peptides to cellular compartments where they are loaded on MHC class I (MHC-I) or MHC class II (MHC-II) molecules. The selective loading and editing of high-affinity immunodominant antigens is orchestrated by molecular chaperones: tapasin/TAP-binding protein, related for MHC-I and HLA-DM for MHC-II. Once peptide/MHC (pMHC) complexes are assembled, following various steps of quality control, they are delivered to the cell surface, where they are available for identification by αβ receptors on CD8+ or CD4+ T lymphocytes. In addition, recognition of cell surface peptide/MHC-I complexes by natural killer cell receptors plays a regulatory role in some aspects of the innate immune response. Many of the components of the pathways of antigen processing and presentation and of T cell receptor (TCR)-mediated signaling have been studied extensively by biochemical, genetic, immunological, and structural approaches over the past several decades. Until recently, however, dynamic aspects of the interactions of peptide with MHC, MHC with molecular chaperones, or of pMHC with TCR have been difficult to address experimentally, although computational approaches such as molecular dynamics (MD) simulations have been illuminating. Studies exploiting X-ray crystallography, cryo-electron microscopy, and multidimensional nuclear magnetic resonance (NMR) spectroscopy are beginning to reveal the importance of molecular flexibility as it pertains to peptide loading onto MHC molecules, the interactions between pMHC and TCR, and subsequent TCR-mediated signals. In addition, recent structural and dynamic insights into how molecular chaperones define peptide selection and fine-tune the MHC displayed antigen repertoire are discussed. Here, we offer a review of current knowledge that highlights experimental data obtained by X-ray crystallography and multidimensional NMR methodologies. Collectively, these findings strongly support a multifaceted role for protein plasticity and conformational dynamics throughout the antigen processing and presentation pathway in dictating antigen selection and recognition.
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Affiliation(s)
- Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Nathan A May
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Michael G Mage
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Lisa F Boyd
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Andrew C McShan
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA, United States
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, United States
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McShan AC, Natarajan K, Kumirov VK, Flores-Solis D, Jiang J, Badstübner M, Toor JS, Bagshaw CR, Kovrigin EL, Margulies DH, Sgourakis NG. Peptide exchange on MHC-I by TAPBPR is driven by a negative allostery release cycle. Nat Chem Biol 2018; 14:811-820. [PMID: 29988068 PMCID: PMC6202177 DOI: 10.1038/s41589-018-0096-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 05/02/2018] [Accepted: 05/21/2018] [Indexed: 01/09/2023]
Abstract
Chaperones TAPBPR and tapasin associate with class-I major histocompatibility complexes (MHC-I) to promote optimization (editing) of peptide cargo. Here, we use solution NMR to investigate the mechanism of peptide exchange. We identify TAPBPR-induced conformational changes on conserved MHC-I molecular surfaces, consistent with our independently determined X-ray structure of the complex. Dynamics present in the empty MHC-I are stabilized by TAPBPR, and become progressively dampened with increasing peptide occupancy. Incoming peptides are recognized according to the global stability of the final pMHC-I product, and anneal in a native-like conformation to be edited by TAPBPR. Our results demonstrate an inverse relationship between MHC-I peptide occupancy and TAPBPR binding affinity, where the lifetime and structural features of transiently bound peptides controls the regulation of a conformational switch, located near the TAPBPR binding site, which triggers TAPBPR release. These results suggest a similar mechanism for the function of tapasin in the peptide-loading complex.
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Affiliation(s)
- Andrew C McShan
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Kannan Natarajan
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MA, USA
| | - Vlad K Kumirov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - David Flores-Solis
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Jiansheng Jiang
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MA, USA
| | - Mareike Badstübner
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Jugmohit S Toor
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | - Clive R Bagshaw
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA
| | | | - David H Margulies
- Molecular Biology Section, Laboratory of Immune System Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MA, USA
| | - Nikolaos G Sgourakis
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, CA, USA.
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47
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48
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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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49
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Courtney AH, Lo WL, Weiss A. TCR Signaling: Mechanisms of Initiation and Propagation. Trends Biochem Sci 2017; 43:108-123. [PMID: 29269020 DOI: 10.1016/j.tibs.2017.11.008] [Citation(s) in RCA: 315] [Impact Index Per Article: 45.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 11/21/2017] [Accepted: 11/21/2017] [Indexed: 10/18/2022]
Abstract
The mechanisms by which a T cell detects antigen using its T cell antigen receptor (TCR) are crucial to our understanding of immunity and the harnessing of T cells therapeutically. A hallmark of the T cell response is the ability of T cells to quantitatively respond to antigenic ligands derived from pathogens while remaining inert to similar ligands derived from host tissues. Recent studies have revealed exciting properties of the TCR and the behaviors of its signaling effectors that are used to detect and discriminate between antigens. Here we highlight these recent findings, focusing on the proximal TCR signaling molecules Zap70, Lck, and LAT, to provide mechanistic models and insights into the exquisite sensitivity and specificity of the TCR.
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Affiliation(s)
- Adam H Courtney
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute (HHMI), San Francisco, CA 94143, USA
| | - Wan-Lin Lo
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute (HHMI), San Francisco, CA 94143, USA
| | - Arthur Weiss
- Division of Rheumatology, Rosalind Russell and Ephraim P. Engleman Arthritis Research Center, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA; Howard Hughes Medical Institute (HHMI), San Francisco, CA 94143, USA.
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50
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Sharma P, Kranz DM. Subtle changes at the variable domain interface of the T-cell receptor can strongly increase affinity. J Biol Chem 2017; 293:1820-1834. [PMID: 29229779 DOI: 10.1074/jbc.m117.814152] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/03/2017] [Indexed: 11/06/2022] Open
Abstract
Most affinity-maturation campaigns for antibodies and T-cell receptors (TCRs) operate on the residues at the binding site, located within the loops known as complementarity-determining regions (CDRs). Accordingly, mutations in contact residues, or so-called "second shell" residues, that increase affinity are typically identified by directed evolution involving combinatorial libraries. To determine the impact of residues located at a distance from the binding site, here we used single-codon libraries of both CDR and non-CDR residues to generate a deep mutational scan of a human TCR against the cancer antigen MART-1·HLA-A2. Non-CDR residues included those at the interface of the TCR variable domains (Vα and Vβ) and surface-exposed framework residues. Mutational analyses showed that both Vα/Vβ interface and CDR residues were important in maintaining binding to MART-1·HLA-A2, probably due to either structural requirements for proper Vα/Vβ association or direct contact with the ligand. More surprisingly, many Vα/Vβ interface substitutions yielded improved binding to MART-1·HLA-A2. To further explore this finding, we constructed interface libraries and selected them for improved stability or affinity. Among the variants identified, one conservative substitution (F45βY) was most prevalent. Further analysis of F45βY showed that it enhanced thermostability and increased affinity by 60-fold. Thus, introducing a single hydroxyl group at the Vα/Vβ interface, at a significant distance from the TCR·peptide·MHC-binding site, remarkably affected ligand binding. The variant retained a high degree of specificity for MART-1·HLA-A2, indicating that our approach provides a general strategy for engineering improvements in either soluble or cell-based TCRs for therapeutic purposes.
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Affiliation(s)
- Preeti Sharma
- From the Department of Biochemistry, University of Illinois, Urbana, Illinois 61801
| | - David M Kranz
- From the Department of Biochemistry, University of Illinois, Urbana, Illinois 61801
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