Prostaglandin EP3 receptor superactivates adenylyl cyclase via the Gq/PLC/Ca2+ pathway in a lipid raft-dependent manner.
We previously demonstrated that prostaglandin EP3 receptor augments EP2-elicited cAMP formation in COS-7 cells in a G(i/o)-insensitive manner. The purpose of our current study was to identify the signaling pathways involved in EP3-induced augmentation of receptor-stimulated cAMP formation. The enhancing effect of EP3 receptor was irrespective of the C-terminal structure of the EP3 isoform. This EP3 action was abolished by treatment with inhibitors for phospholipase C and intracellular Ca(2+)-related signaling molecules such as U73122, staurosporine, 2-APB and SK&F 96365. Indeed, an EP3 agonist stimulated IP(3) formation and intracellular Ca(2+) mobilization, which was blocked by U73122, but not by pertussis toxin. The enhancing effect by EP3 on cAMP formation was mimicked by both a Ca(2+) ionophore and the activation of a typical G(q)-coupled receptor. Moreover, EP3 was exclusively localized to the raft fraction in COS-7 cells and EP3-elicited augmentation of cAMP formation was abolished by cholesterol depletion and introduction of a dominant negative caveolin-1 mutant. These results suggest that EP3 elicits adenylyl cyclase superactivation via G(q)/phospholipase C activation and intracellular Ca(2+) mobilization in a lipid raft microdomain-dependent manner.
Yamaoka
Kumiko
K
Department of Physiological Chemistry, Kyoto University Graduate School of Pharmaceutical Sciences, Sakyo-ku, Kyoto 606-8501, Japan.
Yano
Akiko
A
Kuroiwa
Kenji
K
Morimoto
Kazushi
K
Inazumi
Tomoaki
T
Hatae
Noriyuki
N
Tabata
Hiroyuki
H
Segi-Nishida
Eri
E
Tanaka
Satoshi
S
Ichikawa
Atsushi
A
Sugimoto
Yukihiko
Y
D000262:Adenylyl Cyclases / Q000096:biosynthesis*; D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D019556:COS Cells; D002118:Calcium / Q000378:metabolism*; D051242:Caveolin 1 / Q000378:metabolism; D002522:Chlorocebus aethiops; D004789:Enzyme Activation; D004963:Estrenes / Q000494:pharmacology; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D021962:Membrane Microdomains / Q000378:metabolism*; D011760:Pyrrolidinones / Q000494:pharmacology; D018078:Receptors, Prostaglandin E / Q000037:antagonists & inhibitors / Q000378:metabolism*; D058307:Receptors, Prostaglandin E, EP2 Subtype; D019311:Staurosporine / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism*
C538758:2-aminoethyl diphenylborinate; D001896:Boron Compounds; D051242:Caveolin 1; D004963:Estrenes; D007093:Imidazoles; D007476:Ionophores; C545644:PTGER2 protein, human; D011760:Pyrrolidinones; D018078:Receptors, Prostaglandin E; D058307:Receptors, Prostaglandin E, EP2 Subtype; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; D010738:Type C Phospholipases; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D000262:Adenylyl Cyclases; D019311:Staurosporine; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole; D002118:Calcium