S1P4 receptor or Endothelial Differentiation Gene-6 (EDG-6) is receptor for sphingosine-1-phosphate (S1P). S1P is a bioactive lipid produced from the metabolism of sphingomyelin. It is an important constituent of serum and regulates cell growth, survival, migration, differentiation and gene expression. Unlike other members of S1P receptor, which are widely expressed, S1P4 exhibits lymphoid tissue-specific expression. EDG-6 has been implicated in regulation of cell shape and motility.