S1PR4 is a G protein-coupled receptor which binds the lipid signaling molecule sphingosine 1-phosphate (S1P). Hence this receptor is also known as S1P4.This gene is a member of the endothelial differentiation, G-protein-coupled (EDG) receptor gene family. EDG receptors bind lysophospholipids or lysosphingolipids as ligands, and are involved in cell signalling in many different cell types. This EDG receptor gene is intronless and is specifically expressed in the lymphoid tissue.Specifically expressed in fetal and adult lymphoid and hematopoietic tissue as well as in lung. Considerable level of expression in adult and fetal spleen as well as adult peripheral leukocytes and lung. Lower expression in adult thymus, lymph node, bone marrow, and appendix as well as in fetal liver, thymus, and lung.