title: Threonine 680 phosphorylation of FLJ00018/PLEKHG2, a Rho family-specific guanine nucleotide exchange factor, by epidermal growth factor receptor signaling regulates cell morphology of Neuro-2a cells.
abstract: FLJ00018/PLEKHG2 is a guanine nucleotide exchange factor for the small GTPases Rac and Cdc42 and has been shown to mediate the signaling pathways leading to actin cytoskeleton reorganization. The function of FLJ00018 is regulated by the interaction of heterotrimeric GTP-binding protein Gβγ subunits or cytosolic actin. However, the details underlying the molecular mechanisms of FLJ00018 activation have yet to be elucidated. In the present study we show that FLJ00018 is phosphorylated and activated by β1-adrenergic receptor stimulation-induced EGF receptor (EGFR) transactivation in addition to Gβγ signaling. FLJ00018 is also phosphorylated and activated by direct EGFR stimulation. The phosphorylation of FLJ00018 by EGFR stimulation is mediated by the Ras/mitogen-activated protein kinase (MAPK) pathway. Through deletion and site-directed mutagenesis studies, we have identified Thr-680 as the major site of phosphorylation by EGFR stimulation. FLJ00018 T680A, in which the phosphorylation site is replaced by alanine, showed a limited response of the Neuro-2a cell morphology to EGF stimulation. Our results provide evidence that stimulation of the Ras/MAPK pathway by EGFR results in FLJ00018 phosphorylation at Thr-680, which in turn controls changes in cell shape.
authors.affiliation: From the United Graduate School of Drug Discovery and Medical Information Sciences and.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Sato
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Sugiyama
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nagase
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kitade
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueda
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D048430:Cell Shape; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology*; D051379:Mice; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D015533:Transcriptional Activation / Q000502:physiology*
chemical_list: D020662:Guanine Nucleotide Exchange Factors; C527535:PLEKHG2 protein, human; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: Epidermal Growth Factor Receptor (EGFR); Guanine Nucleotide Exchange Factor (GEF); Neurite Outgrowth; Protein phosphorylation; Rho GTPases