title: Prostaglandin E2 regulates melanocyte dendrite formation through activation of PKCzeta.
abstract: Prostaglandins are lipid signaling intermediates released by keratinocytes in response to ultraviolet irradiation (UVR) in the skin. The main prostaglandin released following UVR is PGE(2), a ligand for 4 related G-protein-coupled receptors (EP(1), EP(2), EP(3) and EP(4)). Our previous work established that PGE(2) stimulates melanocyte dendrite formation through activation of the EP(1) and EP(3) receptors. The purpose of the present report is to define the signaling intermediates involved in EP(1)- and EP(3)-dependent dendrite formation in human melanocytes. We recently showed that activation of the atypical PKCzeta isoform stimulates melanocyte dendricity in response to treatment with lysophosphatidylcholine. We therefore examined the potential contribution of PKCzeta activation on EP(1)- and EP(3)-dependent dendrite formation in melanocytes. Stimulation of the EP(1) and EP(3) receptors by selective agonists activated PKCzeta, and inhibition of PKCzeta activation abrogated EP(1)- and EP(3)-receptor-mediated melanocyte dendricity. Because of the importance of Rho-GTP binding proteins in the regulation of melanocyte dendricity, we also examined the effect of EP(1) and EP(3) receptor activation on Rac and Rho activity. Neither Rac nor Rho was activated upon treatment with EP(1,3)-receptor agonists. We show that melanocytes express only the EP(3A1) isoform, but not the EP(3B) receptor isoform, previously associated with Rho activation, consistent with a lack of Rho stimulation by EP(3) agonists. Our data suggest that PKCzeta activation plays a predominant role in regulation of PGE(2)-dependent melanocyte dendricity.
authors.affiliation: Department of Dermatology, University of Rochester School of Medicine, Rochester, NY 14642, USA. Glynis_Scott@urmc.rochester.edu
authors.forename: Glynis
authors.initials: G
authors.lastname: Scott
authors.forename: Alex
authors.initials: A
authors.lastname: Fricke
authors.forename: Anne
authors.initials: A
authors.lastname: Fender
authors.forename: Lindy
authors.initials: L
authors.lastname: McClelland
authors.forename: Stacey
authors.initials: S
authors.lastname: Jacobs
mesh_terms: D000818:Animals; D022081:Cell Surface Extensions / Q000378:metabolism*; D015232:Dinoprostone / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D008544:Melanocytes / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018078:Receptors, Prostaglandin E / Q000378:metabolism; D058306:Receptors, Prostaglandin E, EP1 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D015398:Signal Transduction / Q000187:drug effects; D012867:Skin / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020741:rho GTP-Binding Proteins / Q000378:metabolism; D000099221:Protein Kinase C zeta
chemical_list: D015232:Dinoprostone; D011493:Protein Kinase C; D018078:Receptors, Prostaglandin E; D058306:Receptors, Prostaglandin E, EP1 Subtype; D058308:Receptors, Prostaglandin E, EP3 Subtype; D020741:rho GTP-Binding Proteins; D000099221:Protein Kinase C zeta; C545635:PTGER1 protein, human; C545647:PTGER3 protein, human; C545636:Ptger1 protein, mouse; C545648:Ptger3 protein, mouse