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. May be involved in cell migration processes that are specific for lymphocytes (By similarity). Specifically expressed in fetal and adult lymphoid and hematopoietic tissue. Expressed in lung, spleen, thymus and lymph node but absent in other non-lymphatic tissue. Coexpressed with GNA15 at the same relative levels in all tissues examined, with the highest levels in adult spleen and lung. Belongs to the G-protein coupled receptor 1 family.