G-protein coupled receptor for the bioactive lysosphingolipid sphingosine 1-phosphate (S1P) that seems to be coupled to the G(i) subclass of heteromeric G proteins. Signaling leads to the activation of RAC1, SRC, PTK2/FAK1 and MAP kinases. Plays an important role in cell migration, probably via its role in the reorganization of the actin cytoskeleton and the formation of lamellipodia in response to stimuli that increase the activity of the sphingosine kinase SPHK1. Required for normal chemotaxis toward sphingosine 1-phosphate. Embryonic brain. Not detected during blastula or gastrula stages. At the 4-5 somite stage, expressed in the diencephalon just posterior to the optic vesicles, and weakly in the hindbrain. By the 14 somite stage, there is widespread expression in the CNS, particularly in the ventral diencephalon, optic stalks and anterior hindbrain. Belongs to the G-protein coupled receptor 1 family.