title: Organization of the resting TCR in nanoscale oligomers.
abstract: Despite the low affinity of the T-cell antigen receptor (TCR) for its peptide/major histocompatibility complex (pMHC) ligand, T cells are very sensitive to their antigens. This paradox can be resolved if we consider that the TCR may be organized into pre-existing oligomers or nanoclusters. Such structures could improve antigen recognition by increasing the functional affinity (avidity) of the TCR-pMHC interaction and by allowing cooperativity between individual TCRs. Up to approximately 20 TCRs become tightly apposed in these nanoclusters, often in a linear manner, and such structures could reflect a relatively generalized phenomenon: the non-random concentration of membrane receptors in specific areas of the plasma membrane known as protein islands. The association of TCRs into nanoclusters can explain the enhanced kinetics of the pMHC-TCR interaction in two dimensional versus three dimensional systems, but also their existence calls for a revision of the TCR triggering models based on pMHC-induced TCR clustering. Interestingly, the B-cell receptor and the FcεRI have also been shown to form nanoclusters, suggesting that the formation of pre-existing receptor oligomers could be widely used in the immune system.
authors.affiliation: Department of Molecular Immunology, Institute of Biology III, Faculty of Biology, BIOSS Centre for Biological Signaling Studies, University of Freiburg, Freiburg, Germany.
authors.forename: Wolfgang W A
authors.initials: WW
authors.lastname: Schamel
authors.forename: Balbino
authors.initials: B
authors.lastname: Alarcón
mesh_terms: D000818:Animals; D019143:Evolution, Molecular; D006801:Humans; D008968:Molecular Conformation; D046912:Multiprotein Complexes / Q000737:chemistry / Q000378:metabolism*; D049329:Nanostructures; D011940:Receptor Aggregation / Q000276:immunology; D020239:Receptor Cross-Talk / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D046912:Multiprotein Complexes; D011948:Receptors, Antigen, T-Cell