Sphingosine-1-phosphate as an intercellular signaling molecule.
Sphingosine-1-phosphate (Sph-1-P) has been implicated as an intracellular second messenger in many studies. Previously, we found the roles of Sph-1-P as a platelet activating lipid released from stimulated platelets and as a lipid regulator of cell motility. We first investigated the mechanism by which Sph-1-P induces activation in platelets. Although exogenous Sph-1-P activated platelets, intracellular Sph-1-P formed from exogenously added Sph failed to do so. Supporting the notion that exogenous Sph-1-P stimulates platelets from outside, we found that contact of platelet surfaces with Sph-1-P-immobilized glass beads resulted in platelet activation. Using these glass beads, we next found that exogenously added Sph-1-P inhibits F10 cell motility from outside through its specific binding site(s) on the cell. We finally identified putative receptor protein(s) for Sph-1-P on the surface of F10 cells.
Fred Hutchinson Cancer Research Center, University of Washington, Seattle 98104, USA. yigarash@pharm.hokudai.ac.jp
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Igarashi
D000818:Animals; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects; D005898:Glass; D006801:Humans; D008246:Lysophospholipids; D015539:Platelet Activation / Q000187:drug effects; D011956:Receptors, Cell Surface / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled; D049312:Receptors, Lysophospholipid; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000502:physiology; D013552:Swine; D014407:Tumor Cells, Cultured
D008246:Lysophospholipids; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049312:Receptors, Lysophospholipid; C060506:sphingosine 1-phosphate; D013110:Sphingosine