Phytosphingosine 1-phosphate: a high affinity ligand for the S1P(4)/Edg-6 receptor.
It has been reported recently that the phosphorylated form of the immunomodulator FTY720 activates sphingosine 1-phosphate G protein-coupled receptors. Therefore, understanding the biology of this new class of receptors will be important in clarifying the immunological function of bioactive lysosphingolipid ligands. The S1P(4) receptor has generated interest due to its lymphoid tissue distribution. While the S1P(4) receptor binds the prototypical ligand, S1P, a survey of other lysosphingolipids demonstrated that 4D-hydroxysphinganine 1-phosphate, more commonly known as phytosphingosine 1-phosphate (PhS1P), binds to S1P(4) with higher affinity. Using radiolabeled S1P (S133P), the affinity of PhS1P for the S1P(4) receptor is 1.6nM, while that of S1P is nearly 50-fold lower (119+/-20nM). Radiolabeled PhS1P proved to be superior to S133P in routine binding assays due to improved signal-to-noise ratio. The present study demonstrates the utility of a novel radiolabeled probe, PhS133P, for in vitro studies of the S1P(4) receptor pharmacology.
Candelore
Mari Rios
MR
Department of Metabolic Diseases-Diabetes, Merck and Company, Merck Research Laboratories, P.O. Box 2000, Rahway, NJ 07065, USA. mari_candelore@merck.com
Wright
Michael J
MJ
Tota
Laurie M
LM
Milligan
James
J
Shei
Gan-ju
GJ
Bergstrom
James D
JD
Mandala
Suzanne M
SM
D000818:Animals; D050976:Basic-Leucine Zipper Transcription Factors; D001665:Binding Sites; D001667:Binding, Competitive; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D006224:Cricetinae; D007700:Kinetics; D008024:Ligands; D010761:Phosphorus Radioisotopes; D011956:Receptors, Cell Surface / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D049312:Receptors, Lysophospholipid; D029701:Saccharomyces cerevisiae Proteins; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D015534:Trans-Activators / Q000378:metabolism; D016335:Zinc Fingers
D050976:Basic-Leucine Zipper Transcription Factors; D008024:Ligands; D010761:Phosphorus Radioisotopes; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049312:Receptors, Lysophospholipid; C099279:SIP4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D015534:Trans-Activators; C117422:phytosphingosine-1-phosphate; D013110:Sphingosine