Roles of sphingosine 1-phosphate on tumorigenesis

Figure 2 Ceramide-sphingosine-sphingosine 1-phosphate rheostat model. Ceramide, sphingosine, and sphingosine 1-phosphate (S1P) with opposing functions are interconvertible within cells. The balance between ceramide/sphingosine and S1P forms a sphingolipid rheostat model, that is primed for cell death when the balance shifts towards ceramide or sphingosine, or to cell survival or proliferation when S1P levels are increased. This rheostat model also regulates autophagic cell death or survival through targeting to Beclin 1 which interacts with Bcl-2 protein.