title: Point mutation in the fibroblast growth factor receptor eliminates phosphatidylinositol hydrolysis without affecting neuronal differentiation of PC12 cells.
abstract: Fibroblast growth factors (FGF) stimulate growth arrest and differentiation in rat pheochromocytoma PC12 cells. We examined the role of phosphatidylinositol (PI) hydrolysis in FGF-induced differentiation of PC12 cells by exploring the biological and biochemical activity of a mutant FGF receptor 1 (flg) defective in stimulation of PI hydrolysis. We show that point mutation at Tyr-766 (Y766F) of the FGF receptor prevents tyrosine phosphorylation of phospholipase C gamma and eliminates acidic FGF (aFGF)-induced stimulation of PI hydrolysis in PC12 cells. Treatment of PC12 cells expressing either wild-type or the Y766F mutant with aFGF led to tyrosine phosphorylation of Shc, the association of Shc with GRB2, a shift in the electrophoretic mobility of the Ras guanine nucleotide-releasing factor, Sos (son of sevenless), and enhancement in mitogen-activated protein kinase phosphorylation. Moreover, stimulation with aFGF led to a typical neurite outgrowth of PC12 cells expressing either wild-type or the Y766F FGF receptor mutant. These experiments indicate that PI hydrolysis is not essential for FGF-induced neuronal differentiation of PC12 cells. Moreover, the aFGF-induced Ras signaling pathway, which is essential for PC12 cell differentiation, is not affected by elimination of PI hydrolysis.
authors.affiliation: Department of Pharmacology, New York University Medical Center, New York 10016.
authors.forename: T
authors.initials: T
authors.lastname: Spivak-Kroizman
authors.forename: M
authors.initials: M
authors.lastname: Mohammadi
authors.forename: P
authors.initials: P
authors.lastname: Hu
authors.forename: M
authors.initials: M
authors.lastname: Jaye
authors.forename: J
authors.initials: J
authors.lastname: Schlessinger
authors.forename: I
authors.initials: I
authors.lastname: Lax
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D016220:Fibroblast Growth Factor 1 / Q000378:metabolism; D000091344:Filaggrin Proteins; D006801:Humans; D006868:Hydrolysis; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D016716:PC12 Cells; D010716:Phosphatidylinositols / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine; D017354:Point Mutation; D051381:Rats; D017468:Receptors, Fibroblast Growth Factor / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D014162:Transfection; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis
chemical_list: C000717249:FLG protein, human; D000091344:Filaggrin Proteins; D010716:Phosphatidylinositols; D017468:Receptors, Fibroblast Growth Factor; D011994:Recombinant Proteins; D016220:Fibroblast Growth Factor 1; D019000:Phosphotyrosine; D014443:Tyrosine