title: Sphingosylphosphorylcholine antagonizes proton-sensing ovarian cancer G-protein-coupled receptor 1 (OGR1)-mediated inositol phosphate production and cAMP accumulation.
abstract: Ovarian cancer G-protein-coupled receptor 1 (OGR1), previously proposed as a receptor for sphingosylphosphorylcholine (SPC), has recently been identified as a proton-sensing or extracellular pH-responsive G-protein-coupled receptor stimulating inositol phosphate production, reflecting the activation of phospholipase C. In the present study, we found that acidic pH stimulated cAMP accumulation, reflecting the activation of adenylyl cyclase, in addition to inositol phosphate production in OGR1-expressing cells. The cAMP response was hardly affected by the inhibition of phospholipase C. SPC inhibited the acidification-induced actions in a pH-dependent manner, while no OGR1-dependent agonistic action of SPC was observed. Thus, the dose-response curves of the proton-induced actions were shifted to the right in the presence of SPC regardless of stereoisoform. The antagonistic property was also observed for psychosine and glucosylsphingosine. In conclusion, OGR1 stimulation may lead to the activation of adenylyl cyclase in addition to phospholipase C in response to extracellular acidification but not to SPC. However, SPC and related lysolipids antagonize the proton-induced and OGR1-mediated actions.
authors.affiliation: Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Mogi
authors.forename: Hideaki
authors.initials: H
authors.lastname: Tomura
authors.forename: Masayuki
authors.initials: M
authors.lastname: Tobo
authors.forename: Ju-Qiang
authors.initials: JQ
authors.lastname: Wang
authors.forename: Alatangaole
authors.initials: A
authors.lastname: Damirin
authors.forename: Junko
authors.initials: J
authors.lastname: Kon
authors.forename: Mayumi
authors.initials: M
authors.lastname: Komachi
authors.forename: Kinji
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Koichi
authors.initials: K
authors.lastname: Sato
authors.forename: Fumikazu
authors.initials: F
authors.lastname: Okajima
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006863:Hydrogen-Ion Concentration; D007295:Inositol Phosphates / Q000378:metabolism*; D008244:Lysophosphatidylcholines / Q000494:pharmacology; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology; D011609:Psychosine / Q000031:analogs & derivatives / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology; D015290:Second Messenger Systems / Q000187:drug effects* / Q000502:physiology; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: C486281:GPR68 protein, human; D007295:Inositol Phosphates; D008244:Lysophosphatidylcholines; D043562:Receptors, G-Protein-Coupled; C005356:sphingosine phosphorylcholine; D010767:Phosphorylcholine; D011609:Psychosine; C035742:sphingosyl beta-glucoside; D000242:Cyclic AMP; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases; D013110:Sphingosine