Ceramide kinases convert the sphingolipid metabolite ceramide into ceramide-1-phosphate, both key mediators of cellular apoptosis and survival. Ceramide metabolism plays an essential role in the viability of neuronal cells, the membranes of which are particularly rich in sphingolipids. CERK catalyzes specifically the phosphorylation of ceramide to form ceramide 1-phosphate. This enzyme acts efficiently on natural and analog ceramides (C6, C8, C16 ceramides, and C8 dihydroceramide), and to a lesser extent on C2-ceramide and C6-dihydroceramide, but not on other lipids, such as various sphingosines. High level expression is noted in heart, brain, skeletal muscle, kidney and liver; moderate expression in peripheral blood leukocytes and thymus; and low expression in spleen, small intestine, placenta and lung.