Sphingosine-1-phosphate is a ligand for the G protein-coupled receptor EDG-6.
EDG-6 is a recently cloned member of the endothelial differentiation gene (EDG) G protein-coupled receptor family that is expressed in lymphoid and hematopoietic tissue and in the lung. Homology of EDG-6 to the known sphingosine-1-phosphate (SPP) receptors EDG-1, EDG-3, and EDG-5 and lysophosphatidic acid (LPA) receptors EDG-2 and EDG-4 suggested that its ligand may be a lysophospholipid or lysosphingolipid. We examined the binding of [(32)P]SPP to HEK293 cells, transiently transfected with cDNA encoding EDG-6. Binding of [(32)P]SPP was saturable, demonstrating high affinity (K(D) = 63 nmol/L). Binding was also specific for SPP, as only unlabeled SPP and sphinganine-1-phosphate, which lacks the trans double bond at the 4 position, potently displaced radiolabeled SPP. LPA did not compete for binding of SPP at any concentration tested, whereas sphingosylphosphorylcholine competed for binding to EDG-6, but only at very high concentrations. In addition, SPP activated extracellular signal-regulated kinase (Erk) in EDG-6 transfected cells in a pertussis toxin-sensitive manner. These results indicate that EDG-6 is a high affinity receptor for SPP, which couples to a G(i/o) protein, resulting in the activation of growth-related signaling pathways. (Blood. 2000;95:2624-2629)
Van Brocklyn
J R
JR
Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007, USA.
Gräler
M H
MH
Bernhardt
G
G
Hobson
J P
JP
Lipp
M
M
Spiegel
S
S
D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D018014:Gene Transfer Techniques; D006801:Humans; D008024:Ligands; D008246:Lysophospholipids; D011485:Protein Binding; D011869:Radioligand Assay; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology
D008024:Ligands; D008246:Lysophospholipids; D011956:Receptors, Cell Surface; C060506:sphingosine 1-phosphate; D013110:Sphingosine