title: FRS2 alpha attenuates FGF receptor signaling by Grb2-mediated recruitment of the ubiquitin ligase Cbl.
abstract: Attenuation of growth factor signaling is essential for the regulation of developmental processes and tissue homeostasis in most organisms. The product of Cbl protooncogene is one such regulator, which functions as an ubiquitin ligase that ubiquitinates and promotes the degradation of a variety of cell signaling proteins. Here, we demonstrate that Grb2 bound to tyrosine-phosphorylated FRS2 alpha forms a ternary complex with Cbl by means of its Src homology 3 domains resulting in the ubiquitination of fibroblast growth factor (FGF) receptor and FRS2 alpha in response to FGF stimulation. These observations highlight the importance of FRS2 alpha in the assembly of both positive (i.e., Sos, phosphatidylinositol 3-kinase) and negative (i.e., Cbl) signaling proteins to mediate a balanced FGF signal transduction. However, the partial inhibition of FGF receptor down-regulation in FRS2 alpha-/- cells indicates that the attenuation of signaling by FGF receptor is regulated by redundant or multiple mechanisms.
authors: Department of Pharmacology, Sterling Hall of Medicine, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06520, USA.
authors: Andy
authors: A
authors: Wong
authors: Betty
authors: B
authors: Lamothe
authors: Arnold
authors: A
authors: Lee
authors: Joseph
authors: J
authors: Schlessinger
authors: Irit
authors: I
authors: Lax
authors: Arnold
authors: A
authors: Li
mesh_terms: D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D002460:Cell Line; D015536:Down-Regulation; D051380:GRB2 Adaptor Protein; D006367:HeLa Cells; D006801:Humans; D008025:Ligases / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D016716:PC12 Cells; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D050721:Proto-Oncogene Proteins c-cbl; D051381:Rats; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*; D015398:Signal Transduction; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C106534:FRS2 protein, human; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C495949:Grb2 protein, mouse; C495950:Grb2 protein, rat; D008565:Membrane Proteins; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D017468:Receptors, Fibroblast Growth Factor; D025801:Ubiquitin; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D008025:Ligases; C067419:CBL protein, human; C493849:Cbl protein, mouse