title: The GRB2/Sem-5 adaptor protein.
abstract: GRB2/Sem-5 is a 25-kDa adaptor protein which contains a central Src homology type 2 (SH2) domain flanked by two Src homology type 3 (SH3) domains. GRB2/Sem-5 was first identified due to the essential role of the sem-5 gene product in the vulval induction pathway in Caenorhabditis elegans. The SH2 domain of GRB2/Sem-5 binds to a number of tyrosine phosphorylated proteins, most notably the epidermal growth factor receptor, the insulin receptor substrate IRS-1 and another putative adaptor protein, Shc. The SH3 domains bind to Sos, a guanine nucleotide exchange factor for Ras proteins. GRB2/Sem-5 brings together Sos and tyrosine phosphoproteins into a complex and thereby may regulate the nucleotide exchange rate of Ras and hence its activation state.
authors.affiliation: Imperial Cancer Research Fund, London, UK.
authors.forename: J
authors.initials: J
authors.lastname: Downward
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000254:growth & development; D004330:Drosophila / Q000254:growth & development; D066246:ErbB Receptors; D051380:GRB2 Adaptor Protein; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D011506:Proteins / Q000737:chemistry / Q000502:physiology; D020664:Son of Sevenless Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495949:Grb2 protein, mouse; D008565:Membrane Proteins; D011506:Proteins; D020664:Son of Sevenless Proteins; D066246:ErbB Receptors