title: Newly generated T cell receptor microclusters initiate and sustain T cell activation by recruitment of Zap70 and SLP-76.
abstract: T cell receptor (TCR) activation and signaling precede immunological synapse formation and are sustained for hours after initiation. However, the precise physical sites of the initial and sustained TCR signaling are not definitively known. We report here that T cell activation was initiated and sustained in TCR-containing microclusters generated at the initial contact sites and the periphery of the mature immunological synapse. Microclusters containing TCRs, the tyrosine kinase Zap70 and the adaptor molecule SLP-76 were continuously generated at the periphery. TCR microclusters migrated toward the central supramolecular cluster, whereas Zap70 and SLP-76 dissociated from these microclusters before the microclusters coalesced with the TCR-rich central supramolecular cluster. Tyrosine phosphorylation and calcium influx were induced as microclusters formed at the initial contact sites. Inhibition of signaling prevented recruitment of Zap70 into the microclusters. These results indicated that TCR-rich microclusters initiate and sustain TCR signaling.
authors.affiliation: Laboratory for Cell Signaling, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yokosuka
authors.forename: Kumiko
authors.initials: K
authors.lastname: Sakata-Sogawa
authors.forename: Wakana
authors.initials: W
authors.lastname: Kobayashi
authors.forename: Michio
authors.initials: M
authors.lastname: Hiroshima
authors.forename: Akiko
authors.initials: A
authors.lastname: Hashimoto-Tane
authors.forename: Makio
authors.initials: M
authors.lastname: Tokunaga
authors.forename: Michael L
authors.initials: ML
authors.lastname: Dustin
authors.forename: Takashi
authors.initials: T
authors.lastname: Saito
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002478:Cells, Cultured; D017930:Genes, Reporter; D008213:Lymphocyte Activation / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D010750:Phosphoproteins / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013601:T-Lymphocytes / Q000502:physiology*; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D010750:Phosphoproteins; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; C092947:SLP-76 signal Transducing adaptor proteins; D051746:ZAP-70 Protein-Tyrosine Kinase; C497262:Zap70 protein, mouse