Identification of p2y9/GPR23 as a novel G protein-coupled receptor for lysophosphatidic acid, structurally distant from the Edg family.
Lysophosphatidic acid (LPA) is a bioactive lipid mediator with diverse physiological and pathological actions on many types of cells. LPA has been widely considered to elicit its biological functions through three types of G protein-coupled receptors, Edg-2 (endothelial cell differentiation gene-2)/LPA1/vzg-1 (ventricular zone gene-1), Edg-4/LPA2, and Edg-7/LPA3. We identified an orphan G protein-coupled receptor, p2y9/GPR23, as the fourth LPA receptor (LPA4). Membrane fractions of RH7777 cells transiently expressing p2y9/GPR23 displayed a specific binding for 1-oleoyl-LPA with a Kd value of around 45 nm. Competition binding and reporter gene assays showed that p2y9/GPR23 preferred structural analogs of LPA with a rank order of 1-oleoyl- > 1-stearoyl- > 1-palmitoyl- > 1-myristoyl- > 1-alkyl- > 1-alkenyl-LPA. In Chinese hamster ovary cells expressing p2y9/GPR23, 1-oleoyl-LPA induced an increase in intracellular Ca2+ concentration and stimulated adenylyl cyclase activity. Quantitative real-time PCR demonstrated that mRNA of p2y9/GPR23 was significantly abundant in ovary compared with other tissues. Interestingly, p2y9/GPR23 shares only 20-24% amino acid identities with Edg-2/LPA1, Edg-4/LPA2, and Edg-7/LPA3, and phylogenetic analysis also shows that p2y9/GPR23 is far distant from the Edg family. These facts suggest that p2y9/GPR23 has evolved from different ancestor sequences from the Edg family.
Noguchi
Kyoko
K
Department of Biochemistry and Molecular Biology, Faculty of Medicine, The University of Tokyo, Core Research for Evolutional Science and Technology (CREST) of Japan Science and Technology Corporation, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
Ishii
Satoshi
S
Shimizu
Takao
T
D000818:Animals; D001667:Binding, Competitive; D015152:Blotting, Northern; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D017930:Genes, Reporter; D005822:Genetic Vectors; D006801:Humans; D007700:Kinetics; D008024:Ligands; D008246:Lysophospholipids / Q000378:metabolism*; D016716:PC12 Cells; D010802:Phylogeny; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D043562:Receptors, G-Protein-Coupled; D018048:Receptors, Purinergic P2 / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured; D049368:Receptors, Lysophosphatidic Acid
D002118:Calcium; D000242:Cyclic AMP; D008024:Ligands; D008246:Lysophospholipids; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D018048:Receptors, Purinergic P2; C082320:LPAR4 protein, human; D049368:Receptors, Lysophosphatidic Acid