title: PLEKHG2/FLJ00018, a Rho family-specific guanine nucleotide exchange factor, is tyrosine phosphorylated via the EphB2/cSrc signaling pathway.
abstract: PLEKHG2/FLJ00018, a Rho family-specific guanine nucleotide exchange factor (RhoGEF), is activated by heterotrimeric GTP-binding protein (G protein) Gβγ subunits, and in turn activates the small G protein Rac and Cdc42, which have been shown to mediate signaling pathways leading to actin cytoskeletal reorganization. In the present study, we show that co-expression of the constitutively active mutant of cSrc, a non-receptor tyrosine kinase, and PLEKHG2 induced the tyrosine phosphorylation of PLEKHG2 in HEK293 cells. Through deletion and base substitution mutagenesis we have identified Tyr489 of PLEKHG2 as the site phosphorylated by cSrc. Furthermore, using a high-throughput src homology 2 (SH2) domain binding assay, the SH2 domain of ABL1 and the PI 3-kinse regulator subunit (PIK3R3) were identified as candidates for the binding partner of tyrosine-phosphorylated PLEKHG2. The interaction between PLEKHG2 and the full-length of PIK3R3, but not ABL1, occurs in a tyrosine-phosphorylation-dependent manner. Furthermore, PLEKHG2 is tyrosine phosphorylated at Tyr489 by ephrinB2 receptor signaling via cSrc. Investigation of the physiological function of tyrosine phosphorylation at Tyr489 in PLEKHG2 remains a subject for future studies.
authors.affiliation: United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido, Gifu 501-1193, Japan.
authors.forename: Katsuya
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Suzuki
authors.affiliation: Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Yamaguchi
authors.affiliation: United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido, Gifu 501-1193, Japan; Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Kitade
authors.affiliation: Kazusa DNA Research Institute, Kisarazu, Chiba 292-0818, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Nagase
authors.affiliation: United Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Yanagido, Gifu 501-1193, Japan; Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193, Japan. Electronic address: hueda@gifu-u.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ueda
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000081247:CSK Tyrosine-Protein Kinase; D003598:Cytoskeletal Proteins; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D016296:Mutagenesis; D019869:Phosphatidylinositol 3-Kinases / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D036183:Receptor, EphB2 / Q000378:metabolism*; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism; D018909:src Homology Domains; D019061:src-Family Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000081247:CSK Tyrosine-Protein Kinase; D003598:Cytoskeletal Proteins; D020662:Guanine Nucleotide Exchange Factors; D019869:Phosphatidylinositol 3-Kinases; D036183:Receptor, EphB2; D014443:Tyrosine; D019061:src-Family Kinases; C513733:ABI1 protein, human; C527535:PLEKHG2 protein, human; C523442:PIK3R3 protein, human; C586310:EPHB2 protein, human; C000631346:CSK protein, human
keywords: ABL1; EphB; RhoGEF; SH2 domain; Src; Tyrosine phosphorylation