title: Sequential phosphorylation of SLP-76 at tyrosine 173 is required for activation of T and mast cells.
abstract: Cooperatively assembled signalling complexes, nucleated by adaptor proteins, integrate information from surface receptors to determine cellular outcomes. In T and mast cells, antigen receptor signalling is nucleated by three adaptors: SLP-76, Gads and LAT. Three well-characterized SLP-76 tyrosine phosphorylation sites recruit key components, including a Tec-family tyrosine kinase, Itk. We identified a fourth, evolutionarily conserved SLP-76 phosphorylation site, Y173, which was phosphorylated upon T-cell receptor stimulation in primary murine and Jurkat T cells. Y173 was required for antigen receptor-induced phosphorylation of phospholipase C-γ1 (PLC-γ1) in both T and mast cells, and for consequent downstream events, including activation of the IL-2 promoter in T cells, and degranulation and IL-6 production in mast cells. In intact cells, Y173 phosphorylation depended on three, ZAP-70-targeted tyrosines at the N-terminus of SLP-76 that recruit and activate Itk, a kinase that selectively phosphorylated Y173 in vitro. These data suggest a sequential mechanism whereby ZAP-70-dependent priming of SLP-76 at three N-terminal sites triggers reciprocal regulatory interactions between Itk and SLP-76, which are ultimately required to couple active Itk to its substrate, PLC-γ1.
authors: Rappaport Family Institute for Research in the Medical Sciences, The Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
authors: Meirav
authors: M
authors: Sela
authors: Yaron
authors: Y
authors: Bogin
authors: Dvora
authors: D
authors: Beach
authors: Thomas
authors: T
authors: Oellerich
authors: Johanna
authors: J
authors: Lehne
authors: Jennifer E
authors: JE
authors: Smith-Garvin
authors: Mariko
authors: M
authors: Okumura
authors: Elina
authors: E
authors: Starosvetsky
authors: Rachelle
authors: R
authors: Kosoff
authors: Evgeny
authors: E
authors: Libman
authors: Gary
authors: G
authors: Koretzky
authors: Taku
authors: T
authors: Kambayashi
authors: Henning
authors: H
authors: Urlaub
authors: Jürgen
authors: J
authors: Wienands
authors: Jonathan
authors: J
authors: Chernoff
authors: Deborah
authors: D
authors: Yablonski
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008213:Lymphocyte Activation; D008407:Mast Cells / Q000276:immunology*; D051379:Mice; D051966:Phospholipase C gamma / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology*; D014443:Tyrosine / Q000378:metabolism; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D007376:Interleukin-2; D015850:Interleukin-6; D010750:Phosphoproteins; C092947:SLP-76 signal Transducing adaptor proteins; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C080813:emt protein-tyrosine kinase; D051966:Phospholipase C gamma