Figure 1.

Sphingosine metabolic pathway. Ceramide, sphingosine, and sphingosine-1-phosphate can be metabolised into each other via various enzymes. Ceramide is converted into sphingosine through a reversible reaction by ceramidase (CDase) and ceramide synthase (CerS) [18]. Sphingosine frequently converted to sphingosine-1-phosphate via the two sphingosine kinases (SPHK1/2) [19]. S1P is metabolised back to sphingosine via sphingosine phosphate phosphatases (SPPase) or by an irreversible reaction by S1P lyase [19]. S1P is then exported out of the cell via spinster 2 (SPNS2). Created in Biorender.com.