Sphingosine

Sphingosine (2-amino-4-octadecene-1,3-diol) is an 18-carbon amino alcohol with an unsaturated hydrocarbon chain, which forms a primary part of sphingolipids, a class of cell membrane lipids that include sphingomyelin, an important phospholipid.

Functions
Sphingosine can be phosphorylated in vivo via two kinases, sphingosine kinase type 1 and sphingosine kinase type 2. This leads to the formation of sphingosine-1-phosphate, a potent signaling lipid.

Sphingolipid metabolites, such as ceramide, sphingosine and sphingosine-1-phosphate, are lipid signaling molecules involved in diverse cellular processes.

Synthesis
Sphingosine is synthesized from palmitoyl CoA and serine in a condensation required to yield dehydrosphingosine.



Dehydrosphingosine is then reduced by NADPH to dihydrosphingosine (sphinganine), and finally oxidized by FAD to sphingosine.

There is no direct route of synthesis from sphinganine to sphingosine; it has to be acylated first to dihydroceramide, which is then dehydrogenated to ceramide. Sphingosine is formed via degradation of sphingolipid in the lysosome.