A Canis sphingosine-1-phosphate (S1P) receptor isoform 1 (cS1P.sub.1), the
nucleic acid encoding the cS1P.sub.1 receptor, and methods for using the
cS1P.sub.1 receptor and the nucleic acid encoding the cS1P.sub.1 receptor
in assays for identifying analytes which modulate activity of the
cS1P.sub.1 receptor.