title: Glycine-extended gastrin stimulates cell proliferation and migration through a Rho- and ROCK-dependent pathway, not a Rac/Cdc42-dependent pathway.
abstract: Both amidated gastrin (Gamide) and glycine-extended gastrin (Ggly) stimulate gastrointestinal cell proliferation and migration. Binding of Gamide to the cholecystokinin-2 receptor activates small GTP-binding proteins of the Rho family (Rho, Rac, and Cdc42), and dominant-negative mutants of Rho or Cdc42 block Gamide-stimulated cell proliferation and survival. In comparison, little is known about the Ggly signaling transduction pathway leading to cell proliferation and migration. The present study examined the roles of the small G proteins Rho, Rac, and Cdc42 in Ggly-induced proliferation and migration of the mouse gastric epithelial cell line IMGE-5. Ggly stimulated the activation of Rho and its downstream effector protein ROCK. The activation of Rho and ROCK mediated Ggly-induced cell proliferation and migration as inhibition of Rho by C3, or ROCK by Y-27632, completely blocked these effects of Ggly. Ggly also stimulated tyrosine phosphorylation of focal adhesion kinase, and stimulation was reversed by addition of C3 and Y-27632. In contrast to the effects of Rho and ROCK, inhibition of the Rac or Cdc42 pathways by expression of dominant-negative mutants of Rac or Cdc42 did not affect Ggly-induced cell proliferation and migration. These results demonstrate that Ggly stimulates IMGE-5 cell proliferation and migration through a Rho/ROCK-dependent pathway but not via Rac- or Cdc42-dependent pathways.
authors.affiliation: Dept. of Surgery, Univ. of Melbourne, Austin Health, Studley Rd., Heidelberg, Victoria 3084, Australia. hong.he@unimelb.edu.au
authors.forename: Hong
authors.initials: H
authors.lastname: He
authors.forename: Julie
authors.initials: J
authors.lastname: Pannequin
authors.forename: John-Paul
authors.initials: JP
authors.lastname: Tantiongco
authors.forename: Arthur
authors.initials: A
authors.lastname: Shulkes
authors.forename: Graham S
authors.initials: GS
authors.lastname: Baldwin
mesh_terms: D000818:Animals; D018929:Cell Culture Techniques; D002465:Cell Movement; D049109:Cell Proliferation; D005753:Gastric Mucosa / Q000166:cytology; D005755:Gastrins / Q000502:physiology*; D041981:Gastrointestinal Tract / Q000166:cytology* / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D015398:Signal Transduction; D020744:rac GTP-Binding Proteins / Q000502:physiology; D020741:rho GTP-Binding Proteins / Q000502:physiology; D054460:rho-Associated Kinases
chemical_list: D005755:Gastrins; D047908:Intracellular Signaling Peptides and Proteins; C086854:glycine-extended gastrin 17; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D020744:rac GTP-Binding Proteins; D020741:rho GTP-Binding Proteins