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Kumar R, Ferez M, Swamy M, Arechaga I, Rejas MT, Valpuesta JM, Schamel WWA, Alarcon B, van Santen HM. Increased sensitivity of antigen-experienced T cells through the enrichment of oligomeric T cell receptor complexes. Immunity 2011; 35:375-87. [PMID: 21903423 DOI: 10.1016/j.immuni.2011.08.010] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 05/11/2011] [Accepted: 08/23/2011] [Indexed: 12/25/2022]
Abstract
Although memory T cells respond more vigorously to stimulation and they are more sensitive to low doses of antigen than naive T cells, the molecular basis of this increased sensitivity remains unclear. We have previously shown that the T cell receptor (TCR) exists as different-sized oligomers on the surface of resting T cells and that large oligomers are preferentially activated in response to low antigen doses. Through biochemistry and electron microscopy, we now showed that previously stimulated and memory T cells have more and larger TCR oligomers at the cell surface than their naive counterparts. Reconstitution of cells and mice with a point mutant of the CD3ζ subunit, which impairs TCR oligomer formation, demonstrated that the increased size of TCR oligomers was directly responsible for the increased sensitivity of antigen-experienced T cells. Thus, we propose that an "avidity maturation" mechanism underlies T cell antigenic memory.
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Affiliation(s)
- Rashmi Kumar
- Departamento de Biología Celular e Inmunología, Centro Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain
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52
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Schrum AG, Gil D, Turka LA, Palmer E. Physical and functional bivalency observed among TCR/CD3 complexes isolated from primary T cells. THE JOURNAL OF IMMUNOLOGY 2011; 187:870-8. [PMID: 21666056 DOI: 10.4049/jimmunol.1100538] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Unlike BCR and secreted Ig, TCR expression is not thought to occur in a bivalent form. The conventional monovalent model of TCR/CD3 is supported by published studies of complexes solubilized in the detergent digitonin, in which bivalency was not observed. We revisited the issue of TCR valency by examining complexes isolated from primary αβ T cells after solubilization in digitonin. Using immunoprecipitation followed by flow cytometry, we unexpectedly observed TCR/CD3 complexes that contained two TCRs per complex. Standard anti-TCR Abs, being bivalent themselves, tended to bind with double occupancy to bivalent TCRs; this property masked the presence of the second TCR per complex in certain Ab binding assays, which may partially explain why previous data did not reveal these bivalent complexes. We also found that the prevalence of bivalency among fully assembled, mature TCR/CD3 complexes was sufficient to impact the functional performance of immunoprecipitated TCRs in binding antigenic peptide/MHC-Ig fusion proteins. Both TCR positions per bivalent complex required an Ag-specific TCR to effect optimal binding to these soluble ligands. Therefore, we conclude that in primary T cells, TCR/CD3 complexes can be found that are physically and functionally bivalent. The expression of bivalent TCR/CD3 complexes has implications regarding potential mechanisms by which Ag may trigger signaling. It also suggests the possibility that the potential for bivalent expression could represent a general feature of Ag receptors.
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Affiliation(s)
- Adam G Schrum
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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53
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Zhou B, Chen Q, Mallis RJ, Zhang H, Liu JH, Reinherz EL, Wang JH. A conserved hydrophobic patch on Vβ domains revealed by TCRβ chain crystal structures: Implications for pre-TCR dimerization. Front Immunol 2011; 2:5. [PMID: 22566796 PMCID: PMC3341985 DOI: 10.3389/fimmu.2011.00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 02/15/2011] [Indexed: 01/21/2023] Open
Abstract
The αβ T cell receptor (TCR) is a multimeric complex whose β chain plays a crucial role in thymocyte development as well as antigen recognition by mature T lymphocytes. We report here crystal structures of individual β subunits, termed N15β (Vβ5.2Dβ2Jβ2.6Cβ2) and N30β (Vβ13Dβ1Jβ1.1Cβ2), derived from two αβ TCRs specific for the immunodominant vesicular stomatitis virus octapeptide (VSV-8) bound to the murine H-2Kb MHC class I molecule. The crystal packing of the N15β structure reveals a homodimer formed through two Vβ domains. The Vβ/Vβ module is topologically very similar to the Vα/Vβ module in the N15αβ heterodimer. By contrast, in the N30β structure, the Vβ domain’s external hydrophobic CFG face is covered by the neighboring molecule’s Cβ domain. In conjunction with systematic investigation of previously published TCR single-subunit structures, we identified several conserved residues forming a concave hydrophobic patch at the center of the CFG outer face of the Vβ and other V-type Ig-like domains. This hydrophobic patch is shielded from solvent exposure in the crystal packing, implying that it is unlikely to be thermodynamically stable if exposed on the thymocyte surface. Accordingly, we propose a dimeric pre-TCR model distinct from those suggested previously by others and discuss its functional and structural implications.
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Affiliation(s)
- Bo Zhou
- Laboratory of Immunobiology, Dana-Farber Cancer Institute, Harvard Medical School Boston, MA, USA
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54
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Reinherz EL, Acuto O. Molecular T cell biology -- basic and translational challenges in the twenty-first century. Front Immunol 2011; 2:3. [PMID: 22566794 PMCID: PMC3342379 DOI: 10.3389/fimmu.2011.00003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 01/25/2011] [Indexed: 11/13/2022] Open
Affiliation(s)
- Ellis L Reinherz
- Laboratory of Immunobiology, Dana Farber Cancer Institute Boston, MA, USA.
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55
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56
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Arechaga I, Swamy M, Abia D, Schamel WA, Alarcón B, Valpuesta JM. Structural characterization of the TCR complex by electron microscopy. Int Immunol 2010; 22:897-903. [PMID: 21059766 DOI: 10.1093/intimm/dxq443] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Structural information on how the TCR transmits signals upon binding of its antigen peptide MHC molecule ligand is still lacking. The ectodomains of the TCRα/β, CD3εγ and CD3εδ dimers, as well as the transmembrane domain of CD3ζ, have been characterized by X-ray crystallography and nuclear magnetic resonance (NMR). However, no structural data have been obtained for the entire TCR complex. In this study, we have purified the TCR from T cells under native conditions and used electron microscopy to derive a three-dimensional structure. The TCR complex appears as a pear-shaped structure of 180 × 120 × 65 . Furthermore, the use of mAbs has allowed to determine the orientation of the TCRα/β and CD3 subunits and to suggest a model of interactions. Interestingly, the reconstructed TCR is larger than expected for a complex with a αβγεδεζζ stoichiometry. The accommodation of a second TCRαβ to fill in the extra volume is discussed.
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Affiliation(s)
- Ignacio Arechaga
- Departamento de Biología Molecular, Universidad de Cantabria (UC) and Instituto de Biomedicina y Biotecnología de Cantabria, IBBTEC (CSIC-UC-IDICAN), c/Herrera Oria s/n, 39011 Santander, Spain
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57
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Kim ST, Touma M, Takeuchi K, Sun ZYJ, Dave VP, Kappes DJ, Wagner G, Reinherz EL. Distinctive CD3 heterodimeric ectodomain topologies maximize antigen-triggered activation of alpha beta T cell receptors. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2010; 185:2951-9. [PMID: 20660709 PMCID: PMC2936104 DOI: 10.4049/jimmunol.1000732] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The alphabeta TCR has recently been suggested to function as an anisotropic mechanosensor during immune surveillance, converting mechanical energy into a biochemical signal upon specific peptide/MHC ligation of the alphabeta clonotype. The heterodimeric CD3epsilongamma and CD3epsilondelta subunits, each composed of two Ig-like ectodomains, form unique side-to-side hydrophobic interfaces involving their paired G-strands, rigid connectors to their respective transmembrane segments. Those dimers are laterally disposed relative to the alphabeta heterodimer within the TCR complex. In this paper, using structure-guided mutational analysis, we investigate the functional consequences of a striking asymmetry in CD3gamma and CD3delta G-strand geometries impacting ectodomain shape. The uniquely kinked conformation of the CD3gamma G-strand is crucial for maximizing Ag-triggered TCR activation and surface TCR assembly/expression, offering a geometry to accommodate juxtaposition of CD3gamma and TCR beta ectodomains and foster quaternary change that cannot be replaced by the isologous CD3delta subunit's extracellular region. TCRbeta and CD3 subunit protein sequence analyses among Gnathostomata species show that the Cbeta FG loop and CD3gamma subunit coevolved, consistent with this notion. Furthermore, restoration of T cell activation and development in CD3gamma(-/-) mouse T lineage cells by interspecies replacement can be rationalized from structural insights on the topology of chimeric mouse/human CD3epsilondelta dimers. Most importantly, our findings imply that CD3gamma and CD3delta evolved from a common precursor gene to optimize peptide/MHC-triggered alphabeta TCR activation.
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MESH Headings
- Amino Acid Sequence
- Animals
- CD3 Complex/chemistry
- CD3 Complex/genetics
- CD3 Complex/physiology
- Evolution, Molecular
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Molecular Sequence Data
- Organ Culture Techniques
- Protein Multimerization
- Protein Structure, Quaternary
- Protein Structure, Tertiary
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Sheep
- Signal Transduction/genetics
- Signal Transduction/immunology
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Affiliation(s)
- Sun Taek Kim
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
- Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Maki Touma
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
- Department of Medicine, Harvard Medical School, Boston, MA 02115
| | - Koh Takeuchi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Zhen-Yu J. Sun
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Vibhuti P. Dave
- Lymphocyte Development Laboratory, Clinical Research Institute of Montreal, Montreal, Quebec, Canada
| | - Dietmar J. Kappes
- Blood Cell Development and Cancer Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Gerhard Wagner
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115
| | - Ellis L. Reinherz
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
- Department of Medicine, Harvard Medical School, Boston, MA 02115
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58
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Boding L, Nielsen MW, Bonefeld CM, von Essen MR, Nielsen BL, Lauritsen JPH, Hansen AK, Nielsen MM, Kongsbak M, Rubin M, Vennegaard MT, Ødum N, Geisler C. Polymorphisms of the T cell receptor CD3δ and CD3ɛ chains affect anti-CD3 antibody binding and T cell activation. Mol Immunol 2010; 47:2450-7. [DOI: 10.1016/j.molimm.2010.06.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 06/11/2010] [Accepted: 06/21/2010] [Indexed: 11/26/2022]
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59
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Structural biology of the T-cell receptor: insights into receptor assembly, ligand recognition, and initiation of signaling. Cold Spring Harb Perspect Biol 2010; 2:a005140. [PMID: 20452950 DOI: 10.1101/cshperspect.a005140] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The T-cell receptor (TCR)-CD3 complex serves as a central paradigm for general principles of receptor assembly, ligand recognition, and signaling in the immune system. There is no other receptor system that matches the diversity of both receptor and ligand components. The recent expansion of the immunological structural database is beginning to identify key principles of MHC and peptide recognition. The multicomponent assembly of the TCR complex illustrates general principles used by many receptors in the immune system, which rely on basic and acidic transmembrane residues to guide assembly. The intrinsic binding of the cytoplasmic domains of the CD3epsilon and zeta chains to the inner leaflet of the plasma membrane represents a novel mechanism for control of receptor activation: Insertion of critical CD3epsilon tyrosines into the hydrophobic membrane core prevents their phosphorylation before receptor engagement.
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60
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Kuhns MS, Girvin AT, Klein LO, Chen R, Jensen KD, Newell EW, Huppa JB, Lillemeier BF, Huse M, Chien YH, Garcia KC, Davis MM. Evidence for a functional sidedness to the alphabetaTCR. Proc Natl Acad Sci U S A 2010; 107:5094-9. [PMID: 20202921 PMCID: PMC2841884 DOI: 10.1073/pnas.1000925107] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The T cell receptor (TCR) and associated CD3gammaepsilon, deltaepsilon, and zetazeta signaling dimers allow T cells to discriminate between different antigens and respond accordingly, but our knowledge of how these parts fit and work together is incomplete. In this study, we provide additional evidence that the CD3 heterodimers congregate on one side of the TCR in both the alphabeta and gammadeltaTCR-CD3 complexes. We also report that the other side of the alphabetaTCR mediates homotypic alphabetaTCR interactions and signaling. Specifically, an erythropoietin receptor-based dimerization assay was used to show that, upon complex assembly, the CD3epsilon chains of two CD3 heterodimers are arranged side-by-side in both the alphabeta and gammadeltaTCR-CD3 complexes. This system was also used to show that alphabetaTCRs can dimerize in the cell membrane and that mutating the unusual outer strands of the Calpha domain impairs this dimerization. Finally, we present data showing that, for CD4 T cells, the mutations that impair alphabetaTCR dimerization also alter ligand-induced calcium mobilization, TCR accumulation at the site of pMHC contact, and polarization toward the site of antigen contact. These data reveal a "functional-sidedness" to the alphabetaTCR constant region, with dimerization occurring on the side of the TCR opposite from where the CD3 heterodimers are located.
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MESH Headings
- Animals
- Antigen-Presenting Cells/cytology
- CD3 Complex/metabolism
- Calcium Signaling
- Cell Line
- Cell Membrane/metabolism
- Cell Polarity
- Humans
- Intracellular Space/metabolism
- Mice
- Models, Molecular
- Mutation/genetics
- Protein Multimerization
- Protein Structure, Secondary
- Protein Subunits/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, gamma-delta/metabolism
- T-Lymphocytes/cytology
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Affiliation(s)
- Michael S. Kuhns
- Department of Microbiology and Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - Andrew T. Girvin
- Department of Microbiology and Immunology
- Graduate Program in Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - Lawrence O. Klein
- Graduate Program in Biophysics
- Stanford University School of Medicine, Stanford, CA 94305
| | - Rebecca Chen
- CCIS/ITI Summer High School Research Program
- Stanford University School of Medicine, Stanford, CA 94305
| | - Kirk D.C. Jensen
- Department of Microbiology and Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - Evan W. Newell
- Department of Microbiology and Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - Johannes B. Huppa
- Department of Microbiology and Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - Björn F. Lillemeier
- Department of Microbiology and Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - Morgan Huse
- Department of Microbiology and Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - Yueh-hsiu Chien
- Department of Microbiology and Immunology
- Stanford University School of Medicine, Stanford, CA 94305
| | - K. Christopher Garcia
- Department of Molecular and Cellular Physiology
- Department of Structural Biology, and
- The Howard Hughes Medical Institute, Chevy Chase, MD 20815; and
- Stanford University School of Medicine, Stanford, CA 94305
| | - Mark M. Davis
- Department of Microbiology and Immunology
- The Howard Hughes Medical Institute, Chevy Chase, MD 20815; and
- Stanford University School of Medicine, Stanford, CA 94305
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61
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Kim ST, Takeuchi K, Sun ZYJ, Touma M, Castro CE, Fahmy A, Lang MJ, Wagner G, Reinherz EL. The alphabeta T cell receptor is an anisotropic mechanosensor. J Biol Chem 2009; 284:31028-37. [PMID: 19755427 PMCID: PMC2781503 DOI: 10.1074/jbc.m109.052712] [Citation(s) in RCA: 302] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 09/12/2009] [Indexed: 01/06/2023] Open
Abstract
Thymus-derived lymphocytes protect mammalian hosts against virus- or cancer-related cellular alterations through immune surveillance, eliminating diseased cells. In this process, T cell receptors (TCRs) mediate both recognition and T cell activation via their dimeric alphabeta, CD3 epsilon gamma, CD3 epsilon delta, and CD3 zeta zeta subunits using an unknown structural mechanism. Here, site-specific binding topology of anti-CD3 monoclonal antibodies (mAbs) and dynamic TCR quaternary change provide key clues. Agonist mAbs footprint to the membrane distal CD3 epsilon lobe that they approach diagonally, adjacent to the lever-like C beta FG loop that facilitates antigen (pMHC)-triggered activation. In contrast, a non-agonist mAb binds to the cleft between CD3 epsilon and CD3 gamma in a perpendicular mode and is stimulatory only subsequent to an external tangential but not a normal force ( approximately 50 piconewtons) applied via optical tweezers. Specific pMHC but not irrelevant pMHC activates a T cell upon application of a similar force. These findings suggest that the TCR is an anisotropic mechanosensor, converting mechanical energy into a biochemical signal upon specific pMHC ligation during immune surveillance. Activating anti-CD3 mAbs mimic this force via their intrinsic binding mode. A common TCR quaternary change rather than conformational alterations can better facilitate structural signal initiation, given the vast array of TCRs and their specific pMHC ligands.
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MESH Headings
- Animals
- Antibodies, Monoclonal/immunology
- CD3 Complex/immunology
- Cell Line
- Mechanotransduction, Cellular
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Molecular Conformation
- Protein Binding
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
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Affiliation(s)
- Sun Taek Kim
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and
- Departments of Medicine and
| | - Koh Takeuchi
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Zhen-Yu J. Sun
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Maki Touma
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and
- Departments of Medicine and
| | | | - Amr Fahmy
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Matthew J. Lang
- the Departments of Mechanical Engineering and
- **Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Gerhard Wagner
- Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 and
| | - Ellis L. Reinherz
- From the Department of Medical Oncology, Laboratory of Immunobiology, Dana-Farber Cancer Institute and
- Departments of Medicine and
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63
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Abstract
The series of events leading to T-cell activation following antigen recognition has been extensively investigated. Although the exact mechanisms of ligand binding and transmission of this extracellular interaction into a productive intracellular signaling sequence remains incomplete, it has been known for many years that the immunoreceptor tyrosine activation motifs (ITAMs) of the T-cell receptor (TCR):CD3 complex are required for initiation of this signaling cascade because of the recruitment and activation of multiple protein tyrosine kinases, signaling intermediates, and adapter molecules. It however remains unclear why the TCR:CD3 complex requires 10 ITAMs, while many other ITAM-containing immune receptors, such as Fc receptors (FcRs) and the B cell receptor (BCR), contain far fewer ITAMs. We have recently demonstrated that various parameters of T cell development and activation are influenced by the number, as well as location and type, of ITAMs within the TCR:CD3 complex and hence propose that the TCR is capable of 'scalable signaling' that facilitates the initiation and orchestration of diverse T-cell functions. While many of the underlying mechanisms remain hypothetical, this review intends to amalgamate what we have learned from conventional biochemical analyses regarding initiation and diversification of T-cell signaling, with more recent evidence from molecular and fluorescent microscopic analyses, to propose a broader purpose for the TCR:CD3 ITAMs. Rather than simply signal initiation, individual ITAMs may also be responsible for the differential recruitment of signaling and regulatory molecules which ultimately affects T-cell development, activation and differentiation.
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Affiliation(s)
- Clifford S Guy
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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64
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Martínez-Martín N, Risueño RM, Morreale A, Zaldívar I, Fernández-Arenas E, Herranz F, Ortiz AR, Alarcón B. Cooperativity between T cell receptor complexes revealed by conformational mutants of CD3epsilon. Sci Signal 2009; 2:ra43. [PMID: 19671929 DOI: 10.1126/scisignal.2000402] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The CD3epsilon subunit of the T cell receptor (TCR) complex undergoes a conformational change upon ligand binding that is thought to be important for the activation of T cells. To study this process, we built a molecular dynamics model of the transmission of the conformational change within the ectodomains of CD3. The model showed that the CD3 dimers underwent a stiffening effect that was funneled to the base of the CD3epsilon subunit. Mutation of two relevant amino acid residues blocked transmission of the conformational change and the differentiation and activation of T cells. Furthermore, this inhibition occurred even in the presence of excess endogenous CD3epsilon subunits. These results emphasize the importance of the conformational change in CD3epsilon for the activation of T cells and suggest the existence of unforeseen cooperativity between TCR complexes.
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Affiliation(s)
- Nuria Martínez-Martín
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049, Spain
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65
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N-terminal negatively charged residues in CD3varepsilon chains as a phylogenetically conserved trait potentially yielding isoforms with different isoelectric points: analysis of human CD3varepsilon chains. Immunol Lett 2009; 126:8-15. [PMID: 19616027 DOI: 10.1016/j.imlet.2009.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 06/23/2009] [Accepted: 07/09/2009] [Indexed: 11/21/2022]
Abstract
CD3varepsilon chains are essential to the structure, expression and signaling of T cell receptors. Here, we extend to human CD3varepsilon our previous data in mouse CD3varepsilon showing that, in T cells, proteolytic processing of the acidic N-terminal sequence of CD3varepsilon chains generate distinct polypeptide species that can be identified by two-dimension (IEF-SDS PAGE) electrophoresis and immunoblot. This was shown first by showing the processing of a fusion protein of GFP and the extracellular domain of mouse CD3varepsilon (mCD3GFP) expressed in Jurkat cells. Secondly, pI heterogeneity was also found in human CD3varepsilon chains immunoprecipitated from the surface of Jurkat cells or PHA blasts of human blood T lymphocytes. Comparison of CD3varepsilon chains from 27 different species shows that their N-terminal sequences share a strong acidic nature, despite the large differences in terms of length and composition, even among closely related species. Our results suggest that generation of CD3varepsilon chain isoforms with different N-terminal sequence and pI is a general phenomenon. Thus, as previously observed in the mouse, the relative abundance of CD3varepsilon chain species might regulate TCR/CD3 structure and function, including the strength of the interactions between CD3 dimers and the TCR clonotypic receptors, as well as TCR/CD3 activation thresholds. Interestingly, CD3varepsilon chains from 7 out of 27 species studied have putative N-glycosylation (NxS or NxT) motifs in their Ig extracellular domain. Their location, plus the conservation of residues involved in domain organization, the interactions with other CD3 chains, or the TCR, and signal triggering add new data useful to establish a permissive topology for the interaction between CD3 dimers and the TCR chains.
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66
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Grigorian A, Torossian S, Demetriou M. T-cell growth, cell surface organization, and the galectin-glycoprotein lattice. Immunol Rev 2009; 230:232-46. [PMID: 19594640 PMCID: PMC3059806 DOI: 10.1111/j.1600-065x.2009.00796.x] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Basal, activation, and arrest signaling in T cells determines survival, coordinates responses to pathogens, and, when dysregulated, leads to loss of self-tolerance and autoimmunity. At the T-cell surface, transmembrane glycoproteins interact with galectins via their N-glycans, forming a molecular lattice that regulates membrane localization, clustering, and endocytosis of surface receptors. Galectin-T-cell receptor (TCR) binding prevents ligand-independent TCR signaling via Lck by blocking spontaneous clustering and CD4-Lck recruitment to TCR, and in turn F-actin transfer of TCR/CD4-Lck complexes to membrane microdomains. Peptide-major histocompatibility complexes overcome galectin-TCR binding to promote TCR clustering and signaling by Lck at the immune synapse. Galectin also localizes the tyrosine phosphatase CD45 to microdomains and the immune synapse, suppressing basal and activation signaling by Lck. Following activation, membrane turnover increases and galectin binding to cytotoxic T-lymphocyte antigen-4 (CTLA-4) enhances surface expression by inhibiting endocytosis, thereby promoting growth arrest. Galectins bind surface glycoproteins in proportion to the branching and number of N-glycans per protein, the latter an encoded feature of protein sequence. N-glycan branching is conditional to the activity of Golgi N-acetylglucosaminyl transferases I, II, IV and V (Mgat1, 2, 4, and 5) and metabolic supply of their donor substrate UDP-GlcNAc. Genetic and metabolic control of N-glycan branching co-regulate homeostatic set-points for basal, activation, and arrest signaling in T cells and, when disturbed, result in T-cell hyperactivity and autoimmunity.
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Affiliation(s)
- Ani Grigorian
- Department of Neurology, University of California, Irvine, CA, USA
| | - Sevan Torossian
- Department of Neurology, University of California, Irvine, CA, USA
| | - Michael Demetriou
- Department of Neurology, University of California, Irvine, CA, USA
- Department of Microbiology and Molecular Genetics, University of California, Irvine, CA, USA
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67
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Alarcón B, Swamy M, van Santen HM, Schamel WWA. T-cell antigen-receptor stoichiometry: pre-clustering for sensitivity. EMBO Rep 2009; 7:490-5. [PMID: 16670682 PMCID: PMC1479560 DOI: 10.1038/sj.embor.7400682] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2005] [Accepted: 03/15/2006] [Indexed: 11/09/2022] Open
Abstract
The T-cell antigen receptor (TCR x CD3) is a multi-subunit complex that is responsible for triggering an adaptive immune response. It shows high specificity and sensitivity, while having a low affinity for the ligand. Furthermore, T cells respond to antigen over a wide concentration range. The stoichiometry and architecture of TCR x CD3 in the membrane have been under intense scrutiny because they might be the key to explaining its paradoxical properties. This review highlights new evidence that TCR x CD3 is found on intact unstimulated T cells in a monovalent form (one ligand-binding site per receptor) as well as in several distinct multivalent forms. This is in contrast to the TCR x CD3 stoichiometries determined by several biochemical means; however, these data can be explained by the effects of different detergents on the integrity of the receptor. Here, we discuss a model in which the multivalent receptors are important for the detection of low concentrations of ligand and therefore confer sensitivity, whereas the co-expressed monovalent TCR x CD3s allow a wide dynamic range.
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MESH Headings
- Animals
- Humans
- Protein Conformation
- Receptor Aggregation/immunology
- Receptor-CD3 Complex, Antigen, T-Cell/chemistry
- Receptor-CD3 Complex, Antigen, T-Cell/metabolism
- Receptor-CD3 Complex, Antigen, T-Cell/physiology
- Receptors, Antigen, T-Cell/chemistry
- Receptors, Antigen, T-Cell/metabolism
- Receptors, Antigen, T-Cell/physiology
- Signal Transduction/immunology
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Affiliation(s)
- Balbino Alarcón
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Mahima Swamy
- Max Planck-Institut für Immunbiologie and University of Freiburg, Stübeweg 51, 79108 Freiburg, Germany
| | - Hisse M van Santen
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Wolfgang W A Schamel
- Max Planck-Institut für Immunbiologie and University of Freiburg, Stübeweg 51, 79108 Freiburg, Germany
- Tel: +49 761 510 8313; Fax: +49 761 510 8423;
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68
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Beddoe T, Chen Z, Clements CS, Ely LK, Bushell SR, Vivian JP, Kjer-Nielsen L, Pang SS, Dunstone MA, Liu YC, Macdonald WA, Perugini MA, Wilce MC, Burrows SR, Purcell AW, Tiganis T, Bottomley SP, McCluskey J, Rossjohn J. Antigen Ligation Triggers a Conformational Change within the Constant Domain of the αβ T Cell Receptor. Immunity 2009; 30:777-88. [DOI: 10.1016/j.immuni.2009.03.018] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 02/16/2009] [Accepted: 03/17/2009] [Indexed: 10/20/2022]
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69
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Change we can believe in--of the conformational type. Workshop on the Initiation of Antigen Receptor Signaling. EMBO Rep 2009; 10:331-6. [PMID: 19282883 DOI: 10.1038/embor.2009.26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 02/09/2009] [Indexed: 12/12/2022] Open
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70
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Takeuchi K, Yang H, Ng E, Park SY, Sun ZYJ, Reinherz EL, Wagner G. Structural and functional evidence that Nck interaction with CD3epsilon regulates T-cell receptor activity. J Mol Biol 2008; 380:704-16. [PMID: 18555270 DOI: 10.1016/j.jmb.2008.05.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 05/14/2008] [Accepted: 05/15/2008] [Indexed: 01/28/2023]
Abstract
Recruitment of signaling molecules to the cytoplasmic domains of the CD3 subunits of the T-cell receptor (TCR) is crucial for early T-cell activation. These transient associations either do or do not require tyrosine phosphorylation of CD3 immune tyrosine activation motifs (ITAMs). Here we show that the non-ITAM-requiring adaptor protein Nck forms a complex with an atypical PxxDY motif of the CD3epsilon tail, which encompasses Tyr166 within the ITAM and a TCR endocytosis signal. As suggested by the structure of the complex, we find that Nck binding inhibits phosphorylation of the CD3epsilon ITAM by Fyn and Lck kinases in vitro. Moreover, the CD3epsilon-Nck interaction downregulates TCR surface expression upon physiological stimulation in mouse primary lymph node cells. This indicates that Nck performs an important regulatory function in T lymphocytes by inhibiting ITAM phosphorylation and/or removing cell surface TCR via CD3epsilon interaction.
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Affiliation(s)
- Koh Takeuchi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA
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71
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Voss RH, Willemsen RA, Kuball J, Grabowski M, Engel R, Intan RS, Guillaume P, Romero P, Huber C, Theobald M. Molecular design of the Calphabeta interface favors specific pairing of introduced TCRalphabeta in human T cells. THE JOURNAL OF IMMUNOLOGY 2008; 180:391-401. [PMID: 18097040 DOI: 10.4049/jimmunol.180.1.391] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A promising approach to adoptive transfer therapy of tumors is to reprogram autologous T lymphocytes by TCR gene transfer of defined Ag specificity. An obstacle, however, is the undesired pairing of introduced TCRalpha- and TCRbeta-chains with the endogenous TCR chains. These events vary depending on the individual endogenous TCR and they not only may reduce the levels of cell surface-introduced TCR but also may generate hybrid TCR with unknown Ag specificities. We show that such hybrid heterodimers can be generated even by the pairing of human and mouse TCRalpha- and TCRbeta-chains. To overcome this hurdle, we have identified a pair of amino acid residues in the crystal structure of a TCR that lie at the interface of associated TCR Calpha and Cbeta domains and are related to each other by both a complementary steric interaction analogous to a "knob-into-hole" configuration and the electrostatic environment. We mutated the two residues so as to invert the sense of this interaction analogous to a charged "hole-into-knob" configuration. We show that this inversion in the CalphaCbeta interface promotes selective assembly of the introduced TCR while preserving its specificity and avidity for Ag ligand. Noteworthily, this TCR modification was equally efficient on both a Mu and a Hu TCR. Our data suggest that this approach is generally applicable to TCR independently of their Ag specificity and affinity, subset distribution, and species of origin. Thus, this strategy may optimize TCR gene transfer to efficiently and safely reprogram random T cells into tumor-reactive T cells.
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Affiliation(s)
- Ralf-Holger Voss
- Medical Clinic (III) and Polyclinic, Department of Hematology and Oncology, Johannes Gutenberg-University, Mainz, Germany.
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72
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A permissive geometry model for TCR–CD3 activation. Trends Biochem Sci 2008; 33:51-7. [DOI: 10.1016/j.tibs.2007.10.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 10/09/2007] [Accepted: 10/19/2007] [Indexed: 01/23/2023]
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73
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74
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Minguet S, Swamy M, Schamel WWA. The short length of the extracellular domain of zeta is crucial for T cell antigen receptor function. Immunol Lett 2007; 116:195-202. [PMID: 18207249 DOI: 10.1016/j.imlet.2007.11.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/27/2007] [Accepted: 11/30/2007] [Indexed: 11/15/2022]
Abstract
The T cell antigen receptor (TCR-CD3) consists of the pMHC-binding TCRalphabeta heterodimer and the signalling dimers CD3deltaepsilon, CD3gammaepsilon and zetazeta. The very short length of the extracellular domain (EC) of the zeta chain is preserved through evolution, however a rational explanation for this observation has not been elucidated. Here, we show that TCR-CD3 assembly is clearly defective when the murine zeta EC domain is artificially enlarged. Under these conditions, the TCR-CD3 complex is super-competent in transducing activation signals upon engagement. Furthermore, the TCR-CD3 complexes containing enlarged zeta EC domains underwent ligand-induced conformation changes with higher efficiency than TCR-CD3 complexes with an unmodified zeta EC domain. Together these data suggest that a short zeta EC domain is needed to correctly assemble the TCR-CD3 complex. When this domain is enlarged, the resulting TCR-CD3 complex is distorted leading to a hyperactive phenotype and enhanced T cell activation.
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Affiliation(s)
- Susana Minguet
- Max Planck Institute of Immunbiology and Faculty of Biology III, University of Freiburg, Stübeweg 51, 79108 Freiburg, Germany
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75
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Common themes in the assembly and architecture of activating immune receptors. Nat Rev Immunol 2007; 7:841-50. [PMID: 17960150 DOI: 10.1038/nri2186] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Each of the many different cell types of the immune system expresses one or several activating receptors which serve a central role in the cell's surveillance function. Many of these cell-surface receptors share a distinctive modular design that consists of a ligand-binding module with no intrinsic signalling capability that is non-covalently associated with one or more dimeric signalling modules. Receptor assembly is directed by unique polar contacts within the transmembrane domains, whereas extracellular contacts can contribute to stability and specificity. This Review discusses the structural basis of receptor assembly and the implications of these findings for the mechanisms of receptor triggering.
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76
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Siegers GM, Swamy M, Fernández-Malavé E, Minguet S, Rathmann S, Guardo AC, Pérez-Flores V, Regueiro JR, Alarcón B, Fisch P, Schamel WWA. Different composition of the human and the mouse gammadelta T cell receptor explains different phenotypes of CD3gamma and CD3delta immunodeficiencies. ACTA ACUST UNITED AC 2007; 204:2537-44. [PMID: 17923503 PMCID: PMC2118495 DOI: 10.1084/jem.20070782] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The γδ T cell receptor for antigen (TCR) comprises the clonotypic TCRγδ, the CD3 (CD3γε and/or CD3δε), and the ζζ dimers. γδ T cells do not develop in CD3γ-deficient mice, whereas human patients lacking CD3γ have abundant peripheral blood γδ T cells expressing high γδ TCR levels. In an attempt to identify the molecular basis for these discordant phenotypes, we determined the stoichiometries of mouse and human γδ TCRs using blue native polyacrylamide gel electrophoresis and anti-TCR–specific antibodies. The γδ TCR isolated in digitonin from primary and cultured human γδ T cells includes CD3δ, with a TCRγδCD3ε2δγζ2 stoichiometry. In CD3γ-deficient patients, this may allow substitution of CD3γ by the CD3δ chain and thereby support γδ T cell development. In contrast, the mouse γδ TCR does not incorporate CD3δ and has a TCRγδCD3ε2γ2ζ2 stoichiometry. CD3γ-deficient mice exhibit a block in γδ T cell development. A human, but not a mouse, CD3δ transgene rescues γδ T cell development in mice lacking both mouse CD3δ and CD3γ chains. This suggests important structural and/or functional differences between human and mouse CD3δ chains during γδ T cell development. Collectively, our results indicate that the different γδ T cell phenotypes between CD3γ-deficient humans and mice can be explained by differences in their γδ TCR composition.
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Affiliation(s)
- Gabrielle M Siegers
- Max-Planck-Institute of Immunobiology and University of Freiburg, 79108 Freiburg, Germany
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77
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Amon MA, Manolios N. Hypothesis: TCR signal transduction--A novel tri-modular signaling system. Mol Immunol 2007; 45:876-80. [PMID: 17915329 DOI: 10.1016/j.molimm.2007.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 08/10/2007] [Indexed: 11/21/2022]
Abstract
Antigenic peptides initiate an immune response in T cells via the T cell receptor (TCR). The TCR itself is widely regarded as one of the most complex receptors in nature, as it is comprised of at least six different subunits, the antigen recognizing TCRalpha and beta chains, and the signal transmitting CD3deltavarepsilon, gammaepsilon, and zeta2 dimers. In order for a signal to be transmitted from the TCR to the cytoplasm, the CD3 chains must "sense" that an antigenic peptide has been presented to the TCRalpha and beta subunits. After accomplishing this, there are a total of 10 different immunoreceptor tyrosine activation motifs (ITAMs) present within the CD3 chains which effectively activate the T cell and hence the immune response. The importance of each CD3 chain and subsequently each ITAM has been the focus of intense research. However, the precise role(s) played by each CD3 chain has remained elusive. Using the immunomodulatory peptide termed core peptide (CP), which is proposed to inhibit TCR activation by disrupting TCR-CD3 interactions, a tri-modular signaling system for T cell activation is proposed. By contrast to the existing two distinct signaling model (zeta2, CD3epsilongamma/epsilondelta), in this model each of the three dimers, CD3gammaepsilon, deltaepsilon, and zeta2, are proposed to act as three separate and distinct signaling modules, performing both specific and redundant functions.
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Affiliation(s)
- Michael A Amon
- Rheumatology Department, Westmead Hospital, Westmead, NSW 2145, Australia
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78
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Bello R, Feito MJ, Ojeda G, Portolés P, Rojo JM. Loss of N-terminal charged residues of mouse CD3 epsilon chains generates isoforms modulating antigen T cell receptor-mediated signals and T cell receptor-CD3 interactions. J Biol Chem 2007; 282:22324-34. [PMID: 17561508 DOI: 10.1074/jbc.m701875200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The antigen T cell receptor (TCR)-CD3 complexes present on the cell surface of CD4(+) T lymphocytes and T cell lines express CD3 epsilon chain isoforms with different isoelectric points (pI), with important structural and functional consequences. The pI values of the isoforms fit the predicted pI values of CD3 epsilon chains lacking one, two, and three negatively charged amino acid residues present in the N-terminal region. Different T cells have different ratios of CD3 epsilon chain isoforms. At a high pI, degraded CD3 epsilon isoforms can be better recognized by certain anti-CD3 monoclonal antibodies such as YCD3-1, the ability of which to bind to the TCR-CD3 complex is directly correlated with the pI of CD3 epsilon. The abundance of CD3 epsilon isoforms can be modified by treatment of T cells with the proteinase inhibitor phenanthroline. In addition, these CD3 epsilon isoforms have functional importance. This is shown, first, by the different structure of TCR-CD3 complexes in cells possessing different amounts of isoforms (as observed in surface biotinylation experiments), by their different antigen responses, and by the stronger interaction between low pI CD3 epsilon isoforms and the TCR. Second, incubation of cells with phenanthroline diminished the proportion of degraded high pI CD3 epsilon isoforms, but also the ability of the cells to deliver early TCR activation signals. Third, cells expressing mutant CD3 epsilon chains lacking N-terminal acid residues showed facilitated recognition by antibody YCD3-1 and enhanced TCR-mediated activation. Furthermore, the binding avidity of antibody YCD3-1 was different in distinct thymus populations. These results suggest that changes in CD3 epsilon N-terminal chains might help to fine-tune the response of the TCR to its ligands in distinct activation situations or in thymus selection.
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Affiliation(s)
- Raquel Bello
- Departamento de Fisiopatología Celular y Molecular, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, E-28040 Madrid, Spain
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79
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Kuhns MS, Davis MM. Disruption of extracellular interactions impairs T cell receptor-CD3 complex stability and signaling. Immunity 2007; 26:357-69. [PMID: 17368054 DOI: 10.1016/j.immuni.2007.01.015] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 12/13/2006] [Accepted: 01/29/2007] [Indexed: 12/19/2022]
Abstract
The alphabeta T cell antigen receptor (TCR), in complex with the CD3deltavarepsilon, gammavarepsilon, and zetazeta signaling subunits, is the chief determinant for specific CD4(+) and CD8(+) T cell responses to self and foreign antigens. Although transmembrane domain charge interactions are critical for the assembly of the complex, the location of extracellular contacts between the TCR and CD3 subunits and their contributions to stability and signal transduction have not been defined. Here we used mutagenesis to demonstrate that the CD3deltavarepsilon and CD3gammavarepsilon subunits interact with the TCR via adjacent Calpha DE and Cbeta CC' loops, respectively. The TCR-CD3deltavarepsilon interactions helped stabilize CD3gammavarepsilon within the complex and were important for normal T cell and thymocyte responses to TCR engagement. These data demonstrate that extracellular TCR-CD3 subunit interactions contribute to the structural integrity and function of this multisubunit receptor.
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MESH Headings
- Amino Acid Sequence
- CD3 Complex/chemistry
- CD3 Complex/genetics
- CD3 Complex/immunology
- Humans
- Models, Molecular
- Molecular Sequence Data
- Mutagenesis
- Mutation
- Protein Structure, Tertiary
- Protein Subunits
- Receptors, Antigen, T-Cell, alpha-beta/chemistry
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Signal Transduction
- Thymus Gland/cytology
- Thymus Gland/immunology
- Tumor Cells, Cultured
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Affiliation(s)
- Michael S Kuhns
- Howard Hughes Medical Institute and Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA
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80
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Abstract
The immune system can be roughly divided into innate and adaptive compartments. The adaptive compartment includes the B and T lymphocytes, whose antigen receptors are generated by recombination of gene segments. The consequence is that the creation of self-reactive lymphocytes is unavoidable. For the host to remain viable, the immune system has evolved a strategy for removing autoimmune lymphocytes during development. This review discusses how T lymphocytes are generated, how they recognize antigens, and how their antigen receptor directs the removal of self-reactive T cells.
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Affiliation(s)
- Ed Palmer
- Laboratory of Transplantation Immunology, Departments of Nephrology and Research, University Hospital Basel, Basel, Switzerland.
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81
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Touma M, Sun ZYJ, Clayton LK, Marissen WE, Kruisbeek AM, Wagner G, Reinherz EL. Importance of the CD3γ Ectodomain Terminal β-Strand and Membrane Proximal Stalk in Thymic Development and Receptor Assembly. THE JOURNAL OF IMMUNOLOGY 2007; 178:3668-79. [PMID: 17339464 DOI: 10.4049/jimmunol.178.6.3668] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
CD3epsilongamma and CD3epsilondelta are noncovalent heterodimers; each consists of Ig-like extracellular domains associated side-to-side via paired terminal beta-strands that are linked to individual subunit membrane proximal stalk segments. CD3epsilon, CD3gamma, and CD3delta stalks contain the RxCxxCxE motif. To investigate the functional importance of a CD3 stalk and terminal beta-strand, we created a CD3gamma double mutant CD3gamma(C82S/C85S) and a CD3gamma beta-strand triple mutant CD3gamma(Q76S/Y78A/Y79A) for use in retroviral transduction of lymphoid progenitors for comparison with CD3gammawt. Although both mutant CD3gamma molecules reduced association with CD3epsilon in CD3epsilongamma heterodimers, CD3gamma(Q76S/Y78A/Y79A) abrogated surface TCR expression whereas CD3gamma(C82S/C85S) did not. Furthermore, CD3gamma(C82S/C85S) rescued thymic development in CD3gamma(-/-) fetal thymic organ culture. However, the numbers of double-positive and single-positive thymocytes after CD3gamma(C82S/C85S) transduction were significantly reduced despite surface pre-TCR and TCR expression comparable to that of CD3gamma(-/-) thymocytes transduced in fetal thymic organ culture with a retrovirus harboring CD3gammawt cDNA. Furthermore, double-negative thymocyte development was perturbed with attenuated double-negative 3/double-negative 4 maturation and altered surface-expressed CD3epsilongamma, as evidenced by the loss of reactivity with CD3gamma N terminus-specific antisera. Single histidine substitution of either CD3gamma stalk cysteine failed to restore CD3epsilongamma association and conformation in transient COS-7 cell transfection studies. Thus, CD3gamma(C82) and CD3gamma(C85) residues likely are either reduced or form a tight intrachain disulfide loop rather than contribute to a metal coordination site in conjunction with CD3epsilon(C80) and CD3epsilon(C83). The implications of these results for CD3epsilongamma and TCR structure and signaling function are discussed.
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Affiliation(s)
- Maki Touma
- Laboratory of Immunobiology and Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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82
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Liu YY, Wang Z, Thomas J, Goodwin KJ, Stavrou S, Neville DM. Polymorphisms of CD3epsilon in cynomolgus and rhesus monkeys and their relevance to anti-CD3 antibodies and immunotoxins. Immunol Cell Biol 2007; 85:357-62. [PMID: 17325695 DOI: 10.1038/sj.icb.7100042] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The monoclonal antibody FN18 has been used as a marker for monkey T cells and as a T-cell-depleting reagent when conjugated to diphtheria toxin that was mutated to prevent binding to non-targeted cells. The antibody recognizes a conformational epitope on the ectodomain of monkey CD3epsilon and displays a range of binding activity to the T cells from different rhesus and cynomolgus monkeys. Our quantitative fluorescence-activated cell sorting analysis of the FN18 reactivity to T cells from different rhesus and cynomolgus monkeys showed that there are at least three levels of FN18 reactivity in the monkeys tested: high, moderate and low. On the basis of available DNA sequence information, we determined the gene structure of rhesus CD3epsilon chain and designed primers that can be used to amplify and quickly sequence the ectodomain of monkey CD3epsilon. Our sequence analysis revealed that the extent of nucleotide sequence variation in this area is greater than that previously reported. In addition to the amino acids at positions 45 and 50, we demonstrated that position 35 of CD3epsilon was also important and substitution of amino acid A for V at this position greatly reduced T-cell reactivity to FN18. We found that T cells from monkeys with high FN18 reactivity all had V, E and R at positions 35, 45 and 50 in CD3epsilon, respectively; those having low FN18 reactivity were homozygous in CD3epsilon with at least one of the changes: V35 to A, E45 to G and R to 50Q, whereas members in the moderate group are heterozygous, having both V and A, E and G, R and Q at these locations. A cytotoxicity assay revealed that T cells from a heterozygous rhesus monkey with moderate FN18 reactivity were much (about 40 times) less sensitive to a FN18-derived immunotoxin than those from a homozygous rhesus monkey having high FN18 reactivity.
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Affiliation(s)
- Yuan Yi Liu
- Section on Biophysical Chemistry, Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD 20892, USA.
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83
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Recio MJ, Moreno-Pelayo MA, Kiliç SS, Guardo AC, Sanal O, Allende LM, Pérez-Flores V, Mencía A, Modamio-Høybjør S, Seoane E, Regueiro JR. Differential Biological Role of CD3 Chains Revealed by Human Immunodeficiencies. THE JOURNAL OF IMMUNOLOGY 2007; 178:2556-64. [PMID: 17277165 DOI: 10.4049/jimmunol.178.4.2556] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The biological role in vivo of the homologous CD3gamma and delta invariant chains within the human TCR/CD3 complex is a matter of debate, as murine models do not recapitulate human immunodeficiencies. We have characterized, in a Turkish family, two new patients with complete CD3gamma deficiency and SCID symptoms and compared them with three CD3gamma-deficient individuals belonging to two families from Turkey and Spain. All tested patients shared similar immunological features such as a partial TCR/CD3 expression defect, mild alphabeta and gammadelta T lymphocytopenia, poor in vitro proliferative responses to Ags and mitogens at diagnosis, and very low TCR rearrangement excision circles and CD45RA(+) alphabeta T cells. However, intrafamilial and interfamilial clinical variability was observed in patients carrying the same CD3G mutations. Two reached the second or third decade in healthy conditions, whereas the other three showed lethal SCID features with enteropathy early in life. In contrast, all reported human complete CD3delta (or CD3epsilon) deficiencies are in infants with life-threatening SCID and very severe alphabeta and gammadelta T lymphocytopenia. Thus, the peripheral T lymphocyte pool was comparatively well preserved in human CD3gamma deficiencies despite poor thymus output or clinical outcome. We propose a CD3delta >> CD3gamma hierarchy for the relative impact of their absence on the signaling for T cell production in humans.
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MESH Headings
- Adult
- Animals
- CD3 Complex/genetics
- CD3 Complex/immunology
- Child
- Female
- Humans
- Infant
- Leukocyte Common Antigens/genetics
- Leukocyte Common Antigens/immunology
- Lymphopenia/genetics
- Lymphopenia/immunology
- Male
- Mice
- Mutation
- Pedigree
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/immunology
- Receptors, Antigen, T-Cell, gamma-delta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/immunology
- Severe Combined Immunodeficiency/genetics
- Severe Combined Immunodeficiency/immunology
- Spain
- T-Lymphocytes/immunology
- Thymus Gland/immunology
- Turkey
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Affiliation(s)
- María J Recio
- Inmunología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
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84
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Clements CS, Dunstone MA, Macdonald WA, McCluskey J, Rossjohn J. Specificity on a knife-edge: the alphabeta T cell receptor. Curr Opin Struct Biol 2006; 16:787-95. [PMID: 17011774 DOI: 10.1016/j.sbi.2006.09.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2006] [Revised: 08/31/2006] [Accepted: 09/15/2006] [Indexed: 11/27/2022]
Abstract
The interaction between the alphabeta T cell receptor (TCR) and the peptide bound to the major histocompatibility complex class I molecule (pMHC-I) constitutes a central interaction in adaptive immunity. How these receptors interact with such low affinity while maintaining exquisite specificity for peptide antigen and host MHC (MHC-I restriction) remains a challenge to be explained by structural immunologists. Moreover, how this extracellular interaction is transmitted as an intracellular signal via the CD3 complex remains unresolved. Nevertheless, several structures of TCRs, non-liganded and ligated to a defined pMHC-I, combined with detailed biophysical analyses, have provided insight of the structural basis of MHC-I restriction. In addition, structures of isolated CD3 components have enabled T cell signalling mechanisms to be postulated. Recent findings in this area, which include seven distinct TCR/pMHC-I complexes, have fundamental implications in adaptive immunity as well as therapeutic applications to modulate the adaptive immune response.
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Affiliation(s)
- Craig S Clements
- The Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Victoria 3800, Australia
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85
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Horii K, Kahn ML, Herr AB. Structural basis for platelet collagen responses by the immune-type receptor glycoprotein VI. Blood 2006; 108:936-42. [PMID: 16861347 DOI: 10.1182/blood-2006-01-010215] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Activation of circulating platelets by exposed vessel wall collagen is a primary step in the pathogenesis of heart attack and stroke, and drugs to block platelet activation have successfully reduced cardiovascular morbidity and mortality. In humans and mice, collagen activation of platelets is mediated by glycoprotein VI (GPVI), a receptor that is homologous to immune receptors but bears little sequence similarity to known matrix protein adhesion receptors. Here we present the crystal structure of the collagen-binding domain of human GPVI and characterize its interaction with a collagen-related peptide. Like related immune receptors, GPVI contains 2 immunoglobulin-like domains arranged in a perpendicular orientation. Significantly, GPVI forms a back-to-back dimer in the crystal, an arrangement that could explain data previously obtained from cell-surface GPVI inhibition studies. Docking algorithms identify 2 parallel grooves on the GPVI dimer surface as collagen-binding sites, and the orientation and spacing of these grooves precisely match the dimensions of an intact collagen fiber. These findings provide a structural basis for the ability of an immunetype receptor to generate signaling responses to collagen and for the development of GPVI inhibitors as new therapies for human cardiovascular disease.
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Affiliation(s)
- Katsunori Horii
- Department of Molecular Genetics, Biochemistry & Microbiology, University of Cincinnati College of Medicine, 231 Albert Sabin Way, OH 45267-0524, USA
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86
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Thomassen EAJ, Dekking EHA, Thompson A, Franken KL, Sanal O, Abrahams JP, van Tol MJD, Koning F. The Impact of Single Amino Acid Substitutions in CD3γ on the CD3ϵγ Interaction and T-Cell Receptor–CD3 Complex Formation. Hum Immunol 2006; 67:579-88. [PMID: 16916653 DOI: 10.1016/j.humimm.2006.04.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Accepted: 04/28/2006] [Indexed: 01/20/2023]
Abstract
The human T-cell receptor-CD3 complex consists of at least eight polypeptide chains; CD3gamma- and delta-dimers associate with the disulfide linked alphabeta- and zetazeta-dimers to form a functional receptor complex. The exact structure of this complex is still unknown. We now have examined the interaction between CD3gamma and CD3 in human T-cells. For this purpose, we have generated site-directed mutants of CD3gamma that were introduced in human T-cells defective in CD3gamma expression. Cell-surface and intracellular expression of the introduced CD3gamma chains was determined, as was the association with CD3delta, CD3, and the T-cell receptor. Although the introduction of wild type CD3gamma and CD3gamma (78Y-F) fully restored T-cell receptor assembly and expression, the introduction of CD3gamma (82C-S), CD3gamma (85C-S), and CD3gamma (76Q-E) all resulted in an impaired association between CD3gamma and CD3 and a lack of cell-surface expressed CD3gamma. Finally, the introduction of CD3gamma (76Q-L) and CD3gamma (78Y-A) restored the expression of TCR-CD3deltagammazeta2 complexes, although the association between CD3gamma and CD3 was impaired. These results indicate that several amino acids in CD3gamma are essential for an optimal association between CD3gamma and CD3 and the assembly of a cell-surface expressed TCR-CD3deltagammazeta2 complex.
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Affiliation(s)
- E A J Thomassen
- Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, The Netherlands
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87
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Touma M, Chang HC, Sasada T, Handley M, Clayton LK, Reinherz EL. The TCR C beta FG loop regulates alpha beta T cell development. THE JOURNAL OF IMMUNOLOGY 2006; 176:6812-23. [PMID: 16709841 DOI: 10.4049/jimmunol.176.11.6812] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The TCRbeta chain constant domain contains an unusually elongated, solvent-exposed FG loop. This structural element forms one component of an alphabeta TCR cavity against which CD3epsilongamma may abut to facilitate Ag-specific signaling. Consistent with this notion, in the present study we show that N15alphabeta TCR transfectants expressing a FG loop-deleted chain (betaDeltaFG) stimulate less tyrosine protein phosphorylation than those bearing a wild-type beta-chain (betawt) upon TCR cross-linking. Furthermore, coimmunoprecipitation studies suggest a weakened association between the CD3epsilongamma heterodimer and the beta-chain in TCR complexes containing the betaDeltaFG variant. To further investigate the biologic role of the Cbeta FG loop in development, we competitively reconstituted the thymus of Ly5 congenic or RAG-2-/- mice using bone marrow cells from betawt or betaDeltaFG transgenic C57BL/6 (B6) mice. Both betawt and betaDeltaFG precursor cells generate thymocytes representative of all maturational stages. However, betaDeltaFG-expressing thymocytes dominate during subsequent development, resulting in an excess of betaDeltaFG-expressing peripheral T cells with reduced proliferative and cytokine production abilities upon TCR stimulation. Collectively, our results show that the unique Cbeta FG loop appendage primarily controls alphabeta T cell development through selection processes.
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MESH Headings
- Animals
- CD3 Complex/chemistry
- CD3 Complex/metabolism
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/metabolism
- CD8-Positive T-Lymphocytes/pathology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Proliferation
- Cytokines/antagonists & inhibitors
- Cytokines/biosynthesis
- Humans
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Peptide Fragments/deficiency
- Peptide Fragments/genetics
- Peptide Fragments/physiology
- Phosphorylation
- Protein Structure, Tertiary/genetics
- Protein Structure, Tertiary/physiology
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, alpha-beta/physiology
- Sequence Deletion
- Signal Transduction/genetics
- Signal Transduction/immunology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thymus Gland/cytology
- Thymus Gland/immunology
- Thymus Gland/metabolism
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Affiliation(s)
- Maki Touma
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
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88
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Abstract
When T cells encounter antigens via the T cell antigen receptor (TCR), information about the quantity and quality of antigen engagement is relayed to the intracellular signal transduction machinery. This process is poorly understood. The TCR itself lacks a significant intracellular domain. Instead, it is associated with CD3 molecules that contain intracellular signaling domains that couple the TCR/CD3 complex to the downstream signaling machinery. The earliest events in TCR signaling must involve the transfer of information from the antigen binding TCR subunit to the CD3 signaling subunits of the TCR/CD3 complex. Elucidating the structural organization of the TCR with the associated CD3 signaling molecules is necessary for understanding the mechanism by which TCR engagement is coupled to activation. Here, we review the current state of our understanding of the structure and organization of the TCR/CD3 complex.
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Affiliation(s)
- Michael S Kuhns
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA
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89
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Bonvin AMJJ, Boelens R, Kaptein R. NMR analysis of protein interactions. Curr Opin Chem Biol 2006; 9:501-8. [PMID: 16122968 DOI: 10.1016/j.cbpa.2005.08.011] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2005] [Accepted: 08/09/2005] [Indexed: 11/28/2022]
Abstract
Recent technological advances in NMR spectroscopy have alleviated the size limitations for the determination of biomolecular structures in solution. At the same time, novel NMR parameters such as residual dipolar couplings are providing greater accuracy. As this review shows, the structures of protein-protein and protein-nucleic acid complexes up to 50 kDa can now be accurately determined. Although de novo structure determination still requires considerable effort, information on interaction surfaces from chemical shift perturbations is much easier to obtain. Advances in modelling and data-driven docking procedures allow this information to be used for determining approximate structures of biomolecular complexes. As a result, a wealth of information has become available on the way in which proteins interact with other biomolecules. Of particular interest is the fact that these NMR-based methods can be applied to weak and transient protein-protein complexes that are difficult to study by other structural methods.
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Affiliation(s)
- Alexandre M J J Bonvin
- Bijvoet Center for Biomolecular Research, Utrecht University, NL-3584 CH Utrecht, The Netherlands
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90
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Chang HC, Tan K, Ouyang J, Parisini E, Liu JH, Le Y, Wang X, Reinherz EL, Wang JH. Structural and Mutational Analyses of a CD8αβ Heterodimer and Comparison with the CD8αα Homodimer. Immunity 2005; 23:661-71. [PMID: 16356863 DOI: 10.1016/j.immuni.2005.11.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 10/20/2005] [Accepted: 11/16/2005] [Indexed: 12/31/2022]
Abstract
The crystal structure of a recombinant mouse single chain CD8alphabeta ectodomains at 2.4 A resolution reveals paired immunoglobulin variable region-like domains with a striking resemblance to CD8alphaalpha in size, shape, and surface electrostatic potential of complementarity-determining regions (CDR), despite <20% sequence identity between the CD8alpha and CD8beta subunits. Unlike the CD8alpha subunit(s) in the heterodimer or homodimer, the CDR1 loop of CD8beta tilts away from its corresponding CDR2 and CDR3 loops. Consistent with this observation, independent mutational studies reveal that alanine substitutions of residues in the CDR1 loop of CD8beta have no effect on CD8alphabeta coreceptor function, whereas mutations in CD8beta CDR2 and CDR3 loops abolish CD8alphabeta coreceptor activity. The implications of these findings and additional CD8alpha mutational studies for CD8alphabeta- versus CD8alphaalpha-MHCI binding are discussed.
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Affiliation(s)
- Hsiu-Ching Chang
- Laboratory of Immunobiology, Department of Medical Oncology, Dana-Farber Cancer Institute, Department of Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA.
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91
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Schamel WWA, Arechaga I, Risueño RM, van Santen HM, Cabezas P, Risco C, Valpuesta JM, Alarcón B. Coexistence of multivalent and monovalent TCRs explains high sensitivity and wide range of response. ACTA ACUST UNITED AC 2005; 202:493-503. [PMID: 16087711 PMCID: PMC2212847 DOI: 10.1084/jem.20042155] [Citation(s) in RCA: 244] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A long-standing paradox in the study of T cell antigen recognition is that of the high specificity–low affinity T cell receptor (TCR)–major histocompatibility complex peptide (MHCp) interaction. The existence of multivalent TCRs could resolve this paradox because they can simultaneously improve the avidity observed for monovalent interactions and allow for cooperative effects. We have studied the stoichiometry of the TCR by Blue Native–polyacrylamide gel electrophoresis and found that the TCR exists as a mixture of monovalent (αβγɛδɛζζ) and multivalent complexes with two or more ligand-binding TCRα/β subunits. The coexistence of monovalent and multivalent complexes was confirmed by electron microscopy after label fracture of intact T cells, thus ruling out any possible artifact caused by detergent solubilization. We found that although only the multivalent complexes become phosphorylated at low antigen doses, both multivalent and monovalent TCRs are phosphorylated at higher doses. Thus, the multivalent TCRs could be responsible for sensing low concentrations of antigen, whereas the monovalent TCRs could be responsible for dose-response effects at high concentrations, conditions in which the multivalent TCRs are saturated. Thus, besides resolving TCR stoichiometry, these data can explain how T cells respond to a wide range of MHCp concentrations while maintaining high sensitivity.
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Affiliation(s)
- Wolfgang W A Schamel
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid 28049, Spain.
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