title: ET-1 stimulates ERK signaling pathway through sequential activation of PKC and Src in rat myometrial cells.
abstract: In this study, we analyzed in rat myometrial cells the signaling pathways involved in the endothelin (ET)-1-induced extracellular signal-regulated kinase (ERK) activation required for the induction of DNA synthesis. We found that inhibition of protein kinase C (PKC) by Ro-31-8220 abolished ERK activation. Inhibition of phospholipase C (PLC) by U-73122 or of phosphoinositide (PI) 3-kinase by wortmannin partially reduced ERK activation. A similar partial inhibition was observed after treatment with pertussis toxin or PKC downregulation by phorbol ester treatment. The effect of wortmannin was additive with that produced by PKC downregulation but not with that due to pertussis toxin. These results suggest that both diacylglycerol-sensitive PKC, activated by PLC products, and diacylglycerol-insensitive PKC, possibly activated by a G(i)-PI 3-kinase-dependent process, are involved in ET-1-induced ERK activation. These two pathways were found to be activated mainly through the ET(A) receptor subtype. ET-1 and phorbol ester stimulated Src activity in a PKC-dependent manner, both responses being abolished in the presence of Ro-31-8220. Inhibition of Src kinases by PP1 abrogated phorbol ester- and ET-1-induced ERK activation. Finally, ET-1 activated Ras in a PP1- and Ro-31-8220-sensitive manner. Altogether, our results indicate that ET-1 induces ERK activation in rat myometrial cells through the sequential stimulation of PKC, Src, and Ras.
authors.affiliation: Laboratoire de Signalisation et Régulations Cellulaires, Centre National de la Recherche Scientifique Unité Mixte de Recherche 8619, Université de Paris-Sud, 91405 Orsay cedex, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Robin
authors.forename: Isaline
authors.initials: I
authors.lastname: Boulven
authors.forename: Christine
authors.initials: C
authors.lastname: Desmyter
authors.forename: Simone
authors.initials: S
authors.lastname: Harbon
authors.forename: Denis
authors.initials: D
authors.lastname: Leiber
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D019332:Endothelin-1 / Q000494:pharmacology*; D004789:Enzyme Activation / Q000502:physiology; D066246:ErbB Receptors / Q000502:physiology; D005260:Female; D019204:GTP-Binding Proteins / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D008934:Mitogens / Q000494:pharmacology; D009215:Myometrium / Q000166:cytology / Q000201:enzymology; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017479:Receptors, Platelet-Derived Growth Factor / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects; D015533:Transcriptional Activation / Q000502:physiology; D010738:Type C Phospholipases / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology; D018631:ras Proteins / Q000502:physiology; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D019332:Endothelin-1; D008934:Mitogens; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D019869:Phosphatidylinositol 3-Kinases; D066246:ErbB Receptors; D017479:Receptors, Platelet-Derived Growth Factor; D019061:src-Family Kinases; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D018631:ras Proteins