title: Selective activation of G alpha i mediated signalling of S1P3 by FTY720-phosphate.
abstract: The immune modulator FTY720 is phosphorylated in vivo to FTY720 phosphate (FTY-P), which activates four sphingosine 1-phosphate (S1P) receptors including S1P(3). Upon activation with S1P, S1P(3) couples to G(i)- and G(q)-protein-dependent signalling pathways. Here we show that FTY-P selectively activates the S1P(3)-mediated and G(i)-coupled inhibition of adenylyl cyclase. Contemporaneously, it antagonizes the S1P-induced activation of G(q) via S1P(3) in intracellular calcium flux measurements, GTP-binding experiments, and flow cytometric analyses of activation-induced receptor down-regulation. In contrast to S1P, pre-treatment with FTY-P did not desensitize S1P-induced calcium flux or chemotaxis via S1P(3). The lack of receptor desensitization prevented S1P(3)-mediated migration to FTY-P. Human umbilical vein endothelial cells express S1P(1) and S1P(3), and respond to S1P and FTY-P by ERK1/2 phosphorylation and by intracellular calcium release in a pertussis toxin-sensitive manner. But whereas a mixture of S1P and FTY-P was not affecting ERK1/2 phosphorylation, the intracellular calcium flux was hampered with increasing amounts of FTY-P, which points to a cross-talk between S1P(1) and S1P(3). FTY-P is therefore one of the rare ligands which bind to a receptor that couples multiple G-proteins but selectively activates only one signalling pathway.
authors.affiliation: Institute for Immunology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hanover, Germany. sensken.sven-christian@mh-hannover.de
authors.forename: Sven-Christian
authors.initials: SC
authors.lastname: Sensken
authors.forename: Claudia
authors.initials: C
authors.lastname: Stäubert
authors.forename: Petra
authors.initials: P
authors.lastname: Keul
authors.forename: Bodo
authors.initials: B
authors.lastname: Levkau
authors.forename: Torsten
authors.initials: T
authors.lastname: Schöneberg
authors.forename: Markus H
authors.initials: MH
authors.lastname: Gräler
mesh_terms: D000818:Animals; D020013:Calcium Signaling; D002478:Cells, Cultured; D015536:Down-Regulation; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D008246:Lysophospholipids / Q000037:antagonists & inhibitors; D010755:Organophosphates / Q000494:pharmacology*; D051381:Rats; D049349:Receptors, Lysosphingolipid / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology
chemical_list: C525008:FTY 720P; D008246:Lysophospholipids; D010755:Organophosphates; D049349:Receptors, Lysosphingolipid; C060506:sphingosine 1-phosphate; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D013110:Sphingosine