title: Conformational changes in the T cell receptor differentially determine T cell subset development in mice.
abstract: In the thymus, immature T cells differentiate from common precursors to become T cells expressing either the αβ or γδ T cell receptor (TCR) complex. The CD3ε subunit of the TCR complex is thought to transduce ligand-induced conformational changes in the TCR by recruiting the cytosolic adaptor protein Nck. To investigate the role of conformational changes in the TCR in T cell development, we generated mice with a germline mutation (C80G) in the extracellular domain of CD3ε, which prevents the outside-in transmission of conformational changes in the TCR. The development of αβ T cells in the C80G mice was blocked at an early stage that depends on signaling by a precursor form of the TCR. In contrast, the C80G mutation did not impair the development of some subsets of γδ T cells, including Vγ1.1(+) cells; however, development of other γδ T cell subsets was blocked. A similar phenotype was observed in mice with a mutation in the cytoplasmic proline-rich sequence (PRS) of CD3ε, the binding site for Nck. In a genetic complementation test, the PRS CD3ε mutant failed to rescue the wild-type phenotype when expressed in heterozygosity with the C80G mutant. These data suggest that Nck may function as an effector of TCR conformational changes during T cell development. Additional experiments showed differential effects of the C80G mutation on the activation of TCR-dependent signaling pathways, which suggests that there are pathways that are either dependent on or independent of the transmission of conformational change in the receptor.
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Blanco
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
authors.forename: Aldo
authors.initials: A
authors.lastname: Borroto
authors.affiliation: BIOSS Centre for Biological Signalling Studies, Faculty of Biology, University of Freiburg and Max Planck Institute for Immunobiology and Epigenetics, 79108 Freiburg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schamel
authors.affiliation: Institut Pasteur, Unité Limphopoïese, INSERM U668, 75015 Paris, France. balarcon@cbm.uam.es ppereira@pasteur.fr.
authors.forename: Pablo
authors.initials: P
authors.lastname: Pereira
authors.affiliation: Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, 28049 Madrid, Spain. balarcon@cbm.uam.es ppereira@pasteur.fr.
authors.forename: Balbino
authors.initials: B
authors.lastname: Alarcon
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D017252:CD3 Complex / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology*; D005434:Flow Cytometry; D055879:Gene Knock-In Techniques; D005816:Genetic Complementation Test; D018095:Germ-Line Mutation / Q000235:genetics; D047468:Immunoprecipitation; D051379:Mice; D015513:Oncogene Proteins / Q000378:metabolism; D011487:Protein Conformation; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D016176:T-Lymphocyte Subsets / Q000737:chemistry* / Q000166:cytology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D017252:CD3 Complex; C485468:Cd3e protein, mouse; C078332:Nck protein; D015513:Oncogene Proteins; D011948:Receptors, Antigen, T-Cell