title: Identification of the Docking Site for CD3 on the T Cell Receptor β Chain by Solution NMR.
abstract: The T cell receptor (TCR)-CD3 complex is composed of a genetically diverse αβ TCR heterodimer associated noncovalently with the invariant CD3 dimers CD3ϵγ, CD3ϵδ, and CD3ζζ. The TCR mediates peptide-MHC recognition, whereas the CD3 molecules transduce activation signals to the T cell. Although much is known about downstream T cell signaling pathways, the mechanism whereby TCR engagement by peptide-MHC initiates signaling is poorly understood. A key to solving this problem is defining the spatial organization of the TCR-CD3 complex and the interactions between its subunits. We have applied solution NMR methods to identify the docking site for CD3 on the β chain of a human autoimmune TCR. We demonstrate a low affinity but highly specific interaction between the extracellular domains of CD3 and the TCR constant β (Cβ) domain that requires both CD3ϵγ and CD3ϵδ subunits. The mainly hydrophilic docking site, comprising 9-11 solvent-accessible Cβ residues, is relatively small (∼400 Å(2)), consistent with the weak interaction between TCR and CD3 extracellular domains, and devoid of glycosylation sites. The docking site is centered on the αA and αB helices of Cβ, which are located at the base of the TCR. This positions CD3ϵγ and CD3ϵδ between the TCR and the T cell membrane, permitting us to distinguish among several possible models of TCR-CD3 association. We further correlate structural results from NMR with mutational data on TCR-CD3 interactions from cell-based assays.
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, the Departments of Chemistry and Biochemistry and.
authors.forename: Yanan
authors.initials: Y
authors.lastname: He
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742.
authors.forename: Sneha
authors.initials: S
authors.lastname: Rangarajan
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850.
authors.forename: Melissa
authors.initials: M
authors.lastname: Kerzic
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, the Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, China, and.
authors.forename: Ming
authors.initials: M
authors.lastname: Luo
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Chen
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850.
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850.
authors.forename: Yiyuan
authors.initials: Y
authors.lastname: Yin
authors.affiliation: the Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261.
authors.forename: Creg J
authors.initials: CJ
authors.lastname: Workman
authors.affiliation: the Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261.
authors.forename: Kate M
authors.initials: KM
authors.lastname: Vignali
authors.affiliation: the Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261.
authors.forename: Dario A A
authors.initials: DA
authors.lastname: Vignali
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, rmariuzz@umd.edu.
authors.forename: Roy A
authors.initials: RA
authors.lastname: Mariuzza
authors.affiliation: From the W. M. Keck Laboratory for Structural Biology, University of Maryland Institute for Bioscience and Biotechnology Research, Rockville, Maryland 20850, the Departments of Chemistry and Biochemistry and jorban@umd.edu.
authors.forename: John
authors.initials: J
authors.lastname: Orban
mesh_terms: D000595:Amino Acid Sequence; D017252:CD3 Complex / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D009154:Mutation; D017510:Protein Folding; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000737:chemistry / Q000276:immunology
chemical_list: D017252:CD3 Complex; D021122:Protein Subunits; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D016693:Receptors, Antigen, T-Cell, alpha-beta; D011994:Recombinant Proteins
keywords: T-cell receptor (TCR); complex; nuclear magnetic resonance (NMR); signal transduction; structural biology