D-erythro-Sphingosine is formed primarily from the breakdown of ceramide. Sphingosine inhibits PKC and phosphatic acid phosphohydrolase, whereas it activates PLD and DAG kinase. Phosphorylation of sphingosine by SPHK 1 and SPHK 2 produces sphingosine-1-phosphate, a potent bioactive lipid that exhibits a broad spectrum of biological activities including cell proliferation, survival, migration, cytoskeletal organization, and morphogenesis.