title: G protein-coupled APJ receptor signaling induces focal adhesion formation and cell motility.
abstract: APJ, a G protein-coupled receptor, has an endogenous ligand called apelin. APJ and apelain are highly expressed in the cardiovascular system from embryo to adulthood. It has been shown that apelin elicited the migration of APJ-expressing cells, but details of the receptor signaling have not been identified. To address the signal transduction molecular mechanisms of the apelin/APJ-induced cell motility, we established human embryonic kidney 293T cells stably expressing the mouse APJ (APJ/293T). APJ/293T cells exhibited a specific [(Glp65, Nle75, Tyr77) [125I]]-Apelin13 binding activity (Kd = 4.45 nM). Apelin induced Akt/PKB phosphorylation in APJ/293T cells, but not in the intact 293T cells (-/293T cells). This APJ-dependent activation of Akt/PKB was significantly inhibited by the pretreatment of pertussis toxin (PTx) and a PI3K inhibitor, LY29004. In addition, apelin enhanced focal adhesion kinase (FAK) phosphorylation and increased focal adhesion formation with staining for F-actin in APJ/293T cells. PTx and LY29004 significantly suppressed these responses to apelin. Moreover, we examined the migration activity by using a scratch-test. Apelin strongly accelerated the cell motility in APJ/293T cells, and this activity was abolished by PTx and LY29004. These results indicated that the apelin/APJ signaling coupled with the PTx-sensitive G-protein activates Akt/PKB and FAK proteins through PI3K.
authors.affiliation: Center for Tsukuba Advanced Research Alliance, Graduate School of Life and Environmental Sciences, University of Tsukuba, Ten-nodai, Ibaraki 305-8577, Japan.
authors.forename: Yasumi
authors.initials: Y
authors.lastname: Hashimoto
authors.forename: Junji
authors.initials: J
authors.lastname: Ishida
authors.forename: Rie
authors.initials: R
authors.lastname: Yamamoto
authors.forename: Kae
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Sachie
authors.initials: S
authors.lastname: Asada
authors.forename: Yoshitoshi
authors.initials: Y
authors.lastname: Kasuya
authors.forename: Naoki
authors.initials: N
authors.lastname: Mochizuki
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Fukamizu
mesh_terms: D000818:Animals; D000075244:Apelin Receptors; D001667:Binding, Competitive; D002460:Cell Line; D002465:Cell Movement; D022001:Focal Adhesions / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D037342:Pertussis Toxin / Q000494:pharmacology; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000075244:Apelin Receptors; C491285:Aplnr protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D000081082:Phosphoinositide-3 Kinase Inhibitors; D043562:Receptors, G-Protein-Coupled; C495199:apelin-13 peptide; D037342:Pertussis Toxin