Signal Transduction of S1P Receptor (Homo sapiens)
Metabolism of sphingomyelin by the sphingomyelinase, ceramidase (Cer'ase) and the sphingosine kinase (SK) enzymes results in formation of S1P and receptor activation. Autocrine and paracrine modes of receptor activation have been implied but have yet to be rigorously proven. Critical signaling molecules, such as phospholipase C (PLC), ERK, PI3K, and Akt are activated. Active Akt binds to the receptor and phosphorylates the third intracellular loop, which is essential for Rac activation.