title: Activation of P2Y2 receptor induces c-FOS protein through a pathway involving mitogen-activated protein kinases and phosphoinositide 3-kinases in HeLa cells.
abstract: The effects of P2Y2 purinoceptor activation on c-Fos expression and the signaling pathways evoked by extracellular ATP/UTP in HeLa cells were investigated. We found that P2Y2 activation induced c-Fos protein and phosphorylated the extracellular signal-regulated kinases 1 and 2 (ERK1/2). The P2Y2-stimulated c-Fos induction was partly blocked (a) by U73122, a phospholipase C inhibitor, (b) by Gö6976, a conventional PKC inhibitor, (c) by PD098059, a mitogen-activated protein kinase kinase inhibitor, and, moreover, (d) by the inhibitors of phosphoinositide 3-kinases (PI3K), LY294002 and wortmannin. When Gö6976 and PD098059, or Gö6976 and wortmannin, were combined there was a totally inhibition of P2Y2-induced c-Fos increase. Either U73122 or Gö6976 did not inhibit ERK1/2 phosphorylation induced by ATP/UTP, while it was inhibited by LY294002 (or wortmannin) and by staurosporine. Additionally, wortmannin inhibited the cytosol-to-membrane translocation of PKC- epsilon induced by ATP/UTP. These data indicated that agonist-induced PI3K and downstream PKC- epsilon activation mediated the effect of ATP/UTP on ERK1/2 activation. To test the biological consequences of ERK1/2 activation, the effect of P2Y2 on cell functions were examined. P2Y2 stimulation increased cell proliferation and this effect was attenuated by PD098059 in a dose-dependent manner, thereby indicating that the ERK pathway mediates mitogenic signaling by P2Y2. In conclusion, the activation of conventional PKCs through P2Y2 receptor acts in concert with ERK and PI3K/PKC- epsilon pathways to induce c-Fos protein and HeLa cell proliferation.
authors.affiliation: Laboratory Physiology, Dipartimento di Scienze e Tecnologie Biologiche e Ambientali, University of Lecce, Ecotekne, Lecce, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Muscella
authors.forename: Maria Giovanna
authors.initials: MG
authors.lastname: Elia
authors.forename: Simona
authors.initials: S
authors.lastname: Greco
authors.forename: Carlo
authors.initials: C
authors.lastname: Storelli
authors.forename: Santo
authors.initials: S
authors.lastname: Marsigliante
mesh_terms: D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005057:Eukaryotic Cells / Q000187:drug effects / Q000201:enzymology*; D006367:HeLa Cells; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020928:Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism; D051744:Protein Kinase C-epsilon; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000187:drug effects / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000187:drug effects / Q000378:metabolism*; D058473:Receptors, Purinergic P2Y2; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D004791:Enzyme Inhibitors; C546385:P2RY2 protein, human; D016760:Proto-Oncogene Proteins c-fos; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; D019869:Phosphatidylinositol 3-Kinases; C497255:PRKCE protein, human; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon; D020928:Mitogen-Activated Protein Kinases