This gene encodes a member of the G-protein coupled receptor 1 family. The encoded protein is a receptor for the lysophospholipid sphingosine 1-phosphate. The gene product functions in endothelial cells and is involved in vascular and heart development. The gene product mediates HDL and HDL-associated lysophospholipid-induced vasorelaxation, and it coordinates with other lysophospholipid receptors in the process of angiogenesis. [provided by RefSeq, Jan 2010]