title: In vivo association of Grb2 with pp116, a substrate of the T cell antigen receptor-activated protein tyrosine kinase.
abstract: Numerous recent studies have implicated the src homology 2 and 3 domain-containing protein, Grb2, in coupling protein tyrosine kinase signaling pathways with the Ras signaling pathway. Ligation of the T cell antigen receptor results in the activation of both a PTK, and Ras; therefore, we investigated whether Grb2 may serve a similar function in T cells. Here we report that a GST/Grb2 fusion protein associates with several tyrosine phosphoproteins from lysates of T cell antigen receptor-stimulated Jurkat T cells. Two of these proteins, pp36 and pp116, bind to the Grb2 fusion protein with high affinity. Through the use of mutated Grb2 fusion proteins, we demonstrate that pp116 binds the amino-terminal src homology 3 domain of Grb2, the same domain of Grb2 thought to be primarily responsible for its interaction with SOS. We demonstrate further that pp116 associates with Grb2 in vivo, and we provide evidence that in the Jurkat T cell line Grb2 may exist complexed with either pp116 or with SOS.
authors.affiliation: Department of Physiology, University of Iowa College of Medicine, Iowa City 52242.
authors.forename: D G
authors.initials: DG
authors.lastname: Motto
authors.forename: S E
authors.initials: SE
authors.lastname: Ross
authors.forename: J K
authors.initials: JK
authors.lastname: Jackman
authors.forename: Q
authors.initials: Q
authors.lastname: Sun
authors.forename: A L
authors.initials: AL
authors.lastname: Olson
authors.forename: P R
authors.initials: PR
authors.lastname: Findell
authors.forename: G A
authors.initials: GA
authors.lastname: Koretzky
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D001483:Base Sequence; D004789:Enzyme Activation; D051380:GRB2 Adaptor Protein; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D009363:Neoplasm Proteins; D010750:Phosphoproteins; D011506:Proteins; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; D005982:Glutathione Transferase; D020794:Receptor Protein-Tyrosine Kinases