Receptor for the lysosphingolipid sphingosine 1-phosphate (S1P). S1P is a bioactive lysophospholipid that elicits diverse physiological effect on most types of cells and tissues. Is coupled to both the G(i/O)alpha and G(12) subclass of heteromeric G-proteins. Displays antiproliferative effects in transfected CHO-K1 and HEK293 cells. Found almost exclusively in brain and skin. Ubiquitously detected in different brain regions with very prominent expression in lower brain regions such as the midbrain, pons, medulla, and spinal cord. Expressed predominantly within white matter tracts of the brain. Corpus callosum, optic nerve, olfactory tract, anterior commissure, internal and external capsules, fimbra of the hippocampus, mammillary tract, stria medullaris, and white matter of the cerebellum and brain stem all express the receptor. Within the striatum itself white matter fascicles express the receptor. Detected also in spleen and lung. Not observed in heart, liver, skeletal muscle, kidney, or testes. In PC-12 cells, nerve growth factor induces neuronal differentiation and represses expression of the receptor. Down-regulated also by fibroblast growth factor and dibutyryl cAMP. Epidermal growth factor, an agent that does not induce differentiation, does not repress expression. Protein kinase A appears to be an obligatory cellular component in regulation. Belongs to the G-protein coupled receptor 1 family.