title: Activation of a high affinity Gi protein-coupled plasma membrane receptor by sphingosine-1-phosphate.
abstract: Sphingosine-1-phosphate (SPP) has attracted much attention as a possible second messenger controlling cell proliferation and motility and as an intracellular Ca(2+)-releasing agent. Here, we present evidence that SPP activates a G protein-coupled receptor in the plasma membrane of various cells, leading to increase in cytoplasmic Ca2+ concentration ([Ca2+]i), inhibition of adenylyl cyclase, and opening of G protein-regulated potassium channels. In human enbryonic kidney (HEK) cells, SPP potently (EC50, 2 nM) and rapidly increased [Ca2+]i in a pertussis toxin-sensitive manner. Pertussis toxin-sensitive increase in [Ca2+]i was also observed with sphingosylphosphorylcholine (EC50, 460 nM), whereas other sphingolipids, including ceramide-1-phosphate, N-palmitoyl-sphingosine, psychosine, and D-erythro-sphingosine at micromolar concentrations did not or only marginally increased [Ca2+]i. Furthermore, SPP inhibited forskolin-stimulated cAMP accumulation in HEK cells and increased binding of guanosine 5'3-O-(thio) triphosphate to HEK cell membranes. Rapid [Ca2+]i responses were also observed in human transitional bladder carcinoma (J82) cells, monkey COS-1 cells, mouse NIH 3T3 cells, Chinese hamster ovary (CHO-K1) cells, and rat C6 glioma cells, whereas human HL-60 leukemia cells and human erythroleukemia cells failed to respond to SPP. In guinea pig atrial myocytes, SPP activated Gi protein-regulated inwardly rectifying potassium channels. Activation of these channels occurred strictly when SPP was applied at the extracellular face of atrial myocyte plasma membrane as measured in cell-attached and inside-out patch clamp current recordings. We conclude that SPP, in addition to its proposed direct action on intracellular Ca2+ stores, interacts with a high affinity Gi protein-coupled receptor in the plasma membrane of apparently many different cell types.
authors.affiliation: Institut für Pharmakologie, Universität GH Essen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: van Koppen
authors.forename: M
authors.initials: M
authors.lastname: Meyer zu Heringdorf
authors.forename: K T
authors.initials: KT
authors.lastname: Laser
authors.forename: C
authors.initials: C
authors.lastname: Zhang
authors.forename: K H
authors.initials: KH
authors.lastname: Jakobs
authors.forename: M
authors.initials: M
authors.lastname: Bünemann
authors.forename: L
authors.initials: L
authors.lastname: Pott
mesh_terms: D016475:3T3 Cells; D037361:Adenylate Cyclase Toxin; D000818:Animals; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D005576:Colforsin / Q000494:pharmacology; D006224:Cricetinae; D004533:Egtazic Acid / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006168:Guinea Pigs; D006321:Heart / Q000502:physiology; D006801:Humans; D015640:Ion Channel Gating; D008246:Lysophospholipids; D051379:Mice; D037342:Pertussis Toxin; D015221:Potassium Channels / Q000502:physiology; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000502:physiology; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D037361:Adenylate Cyclase Toxin; D008246:Lysophospholipids; D015221:Potassium Channels; D011956:Receptors, Cell Surface; D011976:Receptors, Muscarinic; D010566:Virulence Factors, Bordetella; D005576:Colforsin; C060506:sphingosine 1-phosphate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D004533:Egtazic Acid; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D013110:Sphingosine; D002118:Calcium