title: Identification of a putative membrane receptor for the bioactive phospholipid, lysophosphatidic acid.
abstract: Lysophosphatidic acid (LPA) is a naturally occurring phospholipid with hormone- and growth factor-like activities. Exogenous LPA stimulates GTP-dependent phosphoinositide hydrolysis and inhibits adenylate cyclase in its target cells, but the site of action of LPA is unknown. We now report the identification by photoaffinity labeling of a putative LPA membrane receptor in various LPA-responsive cell types. A 32P-labeled LPA analogue containing a photoreactive fatty acid, [32P]diazirine-LPA, labels a membrane protein of apparent molecular mass of 38-40 kDa in various cell types, including neuronal cells, brain homogenates, carcinoma cells, leukemic cells and normal fibroblasts. Labeling of the 38-40 kDa protein is competitively inhibited by unlabeled 1-oleoyl-LPA (IC50 approximately 10 nM), but not by other phospholipids. Specific labeling is not detected in rat liver membranes or in human neutrophils, which are physiologically unresponsive to LPA. Suramin, an inhibitor of both early and late events in the action of LPA, completely inhibits the binding of photoreactive LPA. We suggest that the 38-40 kDa protein represents a specific LPA cell surface receptor mediating at least part of the multiple cellular responses to LPA.
authors.affiliation: Division of Cellular Biochemistry, The Netherlands Cancer Institute, Amsterdam.
authors.forename: R L
authors.initials: RL
authors.lastname: van der Bend
authors.forename: J
authors.initials: J
authors.lastname: Brunner
authors.forename: K
authors.initials: K
authors.lastname: Jalink
authors.forename: E J
authors.initials: EJ
authors.lastname: van Corven
authors.forename: W H
authors.initials: WH
authors.lastname: Moolenaar
authors.forename: W J
authors.initials: WJ
authors.lastname: van Blitterswijk
mesh_terms: D000345:Affinity Labels; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002413:Cations, Divalent; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003978:Diazomethane / Q000378:metabolism; D006801:Humans; D008246:Lysophospholipids / Q000378:metabolism*; D051379:Mice; D051381:Rats; D011956:Receptors, Cell Surface / Q000032:analysis*; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D013498:Suramin / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D000345:Affinity Labels; D002413:Cations, Divalent; D008246:Lysophospholipids; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D013498:Suramin; D003978:Diazomethane; D002118:Calcium