Figure 2.

Metabolism of sphingolipids. S1P is generated from sphingosine by sphingosine kinases (SphK) in the Catabolic pathway. SphK1 mainly exists in the cytosol and SphK2 exists in the nuclei and mitochondria. Ceramide is generated from sphingomyelin by sphingomyelinases (SMase) in the Sphingomyelin pathway, generated from dihydro‐ceramide by ceramide desaturase (DES) in the De novo pathway, and generated from sphingosine produced in the Salvage and the Catabolic pathways. A‐SMase, acid sphingomyelinase; C1P, ceramide‐1‐phosphate; C1PP, ceramide‐1‐phosphate phosphatase; CDase, ceramidase; CK, ceramide kinase; CS, ceramide synthase; DES, ceramide desaturase; KDS, keto‐dihydro‐sphingosine; S1P, sphingosine‐1‐phosphate; SM synthase, sphingomyelin synthase; SMase, sphingomyelinase; SphK, sphingosine kinase; SPP, sphingosine phosphatase; SPT, serine palmitoyl transferase