Figure 1: Metabolic pathways of ceramide. Under apoptotic stimuli, ceramide is generated primarily by de novo synthesis, through serine palmitoyltransferase- and ceramide synthase-mediated synthesis, and the hydrolysis of sphingomyelin through sphingomyelinase. Furthermore, metabolism of ceramide are regulated by ceramide kinase, sphingosine kinase, ceramide-1-phosphate phosphatase, sphingosine-1-phosphate phosphatase, cerebrosidase, and glucosylceramide synthase.