title: Stimulation of phosphatidylinositol 3-kinase by fibroblast growth factor receptors is mediated by coordinated recruitment of multiple docking proteins.
abstract: The docking protein FRS2 is a major downstream effector that links fibroblast growth factor (FGF) and nerve growth factor receptors with the Ras/mitogen-activated protein kinase signaling cascade. In this report, we demonstrate that FRS2 also plays a pivotal role in FGF-induced recruitment and activation of phosphatidylinositol 3-kinase (PI3-kinase). We demonstrate that tyrosine phosphorylation of FRS2alpha leads to Grb2-mediated complex formation with the docking protein Gab1 and its tyrosine phosphorylation, resulting in the recruitment and activation of PI3-kinase. Furthermore, Grb2 bound to tyrosine-phosphorylated FRS2 through its SH2 domain interacts primarily via its carboxyl-terminal SH3 domain with a proline-rich region in Gab1 and via its amino-terminal SH3 domain with the nucleotide exchange factor Sos1. Assembly of FRS2alpha:Grb2:Gab1 complex induced by FGF stimulation results in activation of PI3-kinase and downstream effector proteins such as the S/T kinase Akt, whose cellular localization and activity are regulated by products of PI3-kinase. These experiments reveal a unique mechanism for generation of signal diversity by growth factor-induced coordinated assembly of a multidocking protein complex that can activate the Ras/mitogen-activated protein kinase cascade to induce cell proliferation and differentiation, and PI3-kinase to activate a mediator of a cell survival pathway.
authors.affiliation: Department of Pharmacology and The Skirball Institute, New York University, Medical School, New York, NY 10016, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Ong
authors.forename: Y R
authors.initials: YR
authors.lastname: Hadari
authors.forename: N
authors.initials: N
authors.lastname: Gotoh
authors.forename: G R
authors.initials: GR
authors.lastname: Guy
authors.forename: J
authors.initials: J
authors.lastname: Schlessinger
authors.forename: I
authors.initials: I
authors.lastname: Lax
mesh_terms: D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D004789:Enzyme Activation; D005346:Fibroblast Growth Factors / Q000378:metabolism / Q000494:pharmacology; D051380:GRB2 Adaptor Protein; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor / Q000235:genetics / Q000378:metabolism*; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D005346:Fibroblast Growth Factors; D051380:GRB2 Adaptor Protein; D008565:Membrane Proteins; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D017346:Protein Serine-Threonine Kinases; D011506:Proteins; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D020794:Receptor Protein-Tyrosine Kinases; D051496:Receptor, Fibroblast Growth Factor, Type 1; D017468:Receptors, Fibroblast Growth Factor; C106534:FRS2 protein, human; C098587:GAB1 protein, human; C495948:GRB2 protein, human; C490897:Gab1 protein, mouse; C495949:Grb2 protein, mouse; C496348:FGFR1 protein, human; C496349:Fgfr1 protein, mouse; C494918:AKT1 protein, human