title: RhoA- and RhoD-dependent regulatory switch of Galpha subunit signaling by PAR-1 receptors in cellular invasion.
abstract: Thrombin and proteinase-activated receptors (PAR) specifically regulate several functions that markedly enhance the transformation phenotype such as inflammation, cell proliferation, tumor growth, and metastasis. We recently reported that thrombin inhibits cellular invasion induced by src, hepatocyte growth factor (HGF), and leptin in kidney and colonic epithelial cells via predominant activation of the pertussis toxin (PTx) -sensitive G-proteins Galphao/Galphai. We provide pharmacological and biochemical evidence that in the presence of PTx, PAR-1 induced cellular invasion through Galpha12/Galpha13- and RhoA/Rho kinase (ROCK) -dependent signaling. However, inhibition of the endogenous small GTPase RhoA by the C3 exoenzyme, dominant-negative N19-RhoA, activated G26V-RhoD, and activators of the nitric oxide/cGMP pathways conferred invasive activity to PAR-1 via a signaling cascade using Galphaq, phospholipase C (PLC), Ca(2+)/calmodulin myosin light chain kinase (CaM-MLCK), and phosphorylation of MLC. We found that cellular invasion induced by the src oncogene is abrogated by inhibitors of the RhoA/ROCK pathway and is independent of PLC/CaM-MLCK signaling. Our data demonstrate that the RhoA and RhoD small GTPases are acting as a molecular switch of cellular invasion and reveal a novel critical mechanism by which PAR-1 bypass Galphao/i and RhoA inhibition via differential coupling to heterotrimeric G-proteins linked to divergent or convergent biological responses. Our data also indicate that Rho GTPases and ROCK mediate a src-dependent invasion signal in kidney and colonic cancer cells. We conclude that dynamic regulation of Rho GTPases activation and inactivation by oncogenes, growth factors, cGMP-inducing agents, and adhesion molecules can initiate convergent invasion signals controlled by the thrombin PAR-1 in cancer cells.-Nguyen, Q.-D., Faivre, S., Bruyneel, E., Rivat, C., Seto, M., Endo, T., Mareel, M., Emami, S., Gespach, C. RhoA- and RhoD-dependent regulatory switch of Galpha subunit signaling by PAR-1 receptors in cellular invasion.
authors.affiliation: INSERM U482, Signal Transduction and Cellular Functions in Diabetes and Digestive Cancers, Hôpital Saint-Antoine, 75571 Paris Cedex 12, France.
authors.forename: Quang-Dé
authors.initials: QD
authors.lastname: Nguyen
authors.forename: Sandrine
authors.initials: S
authors.lastname: Faivre
authors.forename: Erik
authors.initials: E
authors.lastname: Bruyneel
authors.forename: Christine
authors.initials: C
authors.lastname: Rivat
authors.forename: Minoru
authors.initials: M
authors.lastname: Seto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Endo
authors.forename: Marc
authors.initials: M
authors.lastname: Mareel
authors.forename: Shahin
authors.initials: S
authors.lastname: Emami
authors.forename: Christian
authors.initials: C
authors.lastname: Gespach
mesh_terms: D036002:ADP Ribose Transferases / Q000494:pharmacology; D001905:Botulinum Toxins; D002460:Cell Line; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D029721:Drosophila Proteins; D044365:GTP-Binding Protein alpha Subunits, G12-G13; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D006162:Guanylate Cyclase / Q000378:metabolism; D020962:Heterotrimeric GTP-Binding Proteins / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation; D009361:Neoplasm Invasiveness; D015688:Oncogene Protein pp60(v-src) / Q000494:pharmacology; D037342:Pertussis Toxin; D011506:Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin / Q000819:agonists / Q000378:metabolism*; D015398:Signal Transduction; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029721:Drosophila Proteins; C097161:G protein a49B, Drosophila; D011506:Proteins; D044463:Receptor, PAR-1; D018179:Receptors, Thrombin; D010566:Virulence Factors, Bordetella; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D037342:Pertussis Toxin; D015688:Oncogene Protein pp60(v-src); D001905:Botulinum Toxins; C105243:RHOD protein, human; D044365:GTP-Binding Protein alpha Subunits, G12-G13; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D020962:Heterotrimeric GTP-Binding Proteins; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D006162:Guanylate Cyclase