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.
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.
Kyoko
K
Noguchi
Satoshi
S
Ishii
Takao
T
Shimizu
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