Plasma membrane ceramidase that hydrolyzes sphingolipid ceramides into sphingosine and free fatty acids at neutral pH ( ). Ceramides, sphingosine, and its phosphorylated form sphingosine-1-phosphate are bioactive lipids that mediate cellular signaling pathways regulating several biological processes including cell proliferation, apoptosis and differentiation ( ). Also catalyzes the reverse reaction allowing the synthesis of ceramides from fatty acids and sphingosine (, ). Together with sphingomyelinase, participates in the production of sphingosine and sphingosine-1-phosphate from the degradation of sphingomyelin, a sphingolipid enriched in the plasma membrane of cells . Also participates in the hydrolysis of ceramides from the extracellular milieu allowing the production of sphingosine-1-phosphate inside and outside cells (By similarity). This is the case for instance with the digestion of dietary sphingolipids in the intestinal tract (By similarity).
Subcellular locations: Cell membrane, Membrane raft, Membrane, Caveola, Golgi apparatus membrane, Mitochondrion, Secreted, Extracellular exosome
Enriched in exosomes upon stimulation by cytokine . Enriched in caveolae and lipid rafts (By similarity). The localization to the mitochondrion could not be confirmed .
Subcellular locations: Secreted
Primarily expressed in intestine . Ubiquitously expressed with higher levels in kidney, skeletal muscle and heart . The ubiquitous expression observed for ASAH2 might be an experimental artifact due to the paralog ASAH2B .