title: Cooperation and selectivity of the two Grb2 binding sites of p52Shc in T-cell antigen receptor signaling to Ras family GTPases and Myc-dependent survival.
abstract: Shc proteins participate in a variety of processes regulating cell proliferation, survival and apoptosis. The two ubiquitously expressed isoforms, p52Shc/p46Shc, couple tyrosine kinase receptors to Ras by recruiting Grb2/Sos complexes to a membrane-proximal localization. Tyrosine residues 239/240 and 317 become phosphorylated following receptor engagement and, as such, form two Grb2 binding sites, which have been proposed to be differentially coupled to Myc-dependent survival and to fos-dependent proliferation, respectively. Here, we have addressed the individual function of YY239/240 and Y317 in T-cell antigen receptor (TCR) signaling. We show that p52Shc is phosphorylated on both YY239/240 and Y317 following TCR engagement. Mutation of either YY239/240 or Y317 results in impaired interaction with Grb2 and inhibition of Ras/MAP kinase activation and CD69 induction, supporting a role for both Grb2 binding sites in this function. Substitution of either YY239/240 or Y317 also results in a defective activation of Rac and the coupled stress kinases JNK and p38. Furthermore, mutation of Y317 or, to a larger extent, of YY239/240, results in increased activation-induced cell death, which in cells expressing the FF239/240 mutant is accompanied by impaired TCR-dependent c-myc transcription. The data underline a pleiotropic and nonredundant role of Shc, mediated by both YY239/240 and Y317, in T-cell activation and survival.
authors.affiliation: Department of Evolutionary Biology, University of Siena, Via Aldo Moro 2, Siena 53100, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Patrussi
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Savino
authors.forename: Michela
authors.initials: M
authors.lastname: Pellegrini
authors.forename: Silvia Rossi
authors.initials: SR
authors.lastname: Paccani
authors.forename: Enrica
authors.initials: E
authors.lastname: Migliaccio
authors.forename: Simon
authors.initials: S
authors.lastname: Plyte
authors.forename: Luisa
authors.initials: L
authors.lastname: Lanfrancone
authors.forename: Pier Giuseppe
authors.initials: PG
authors.lastname: Pelicci
authors.forename: Cosima T
authors.initials: CT
authors.lastname: Baldari
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002470:Cell Survival / Q000502:physiology*; D003001:Cloning, Molecular; D051380:GRB2 Adaptor Protein; D016259:Genes, myc; D006801:Humans; D019169:Jurkat Cells; D018613:Microscopy, Confocal; D016296:Mutagenesis; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014162:Transfection; D020703:ras GTPase-Activating Proteins / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D020703:ras GTPase-Activating Proteins