Figure 3.

Phospholipid targets are composed of a phosphatidyl tail including free fatty acid, glycerol, and phosphate. In the phospholipid polar head, choline, serine, ethanolamine, and inositol bind to the phosphatidyl non-polar tail. Sphingomyelin is the only one cell membrane phospholipid not derived from a glycerol but from an aminoalcohol sphingosine; SM is composed of a core ceramide (i.e. sphingosine and free fatty acid tail) and contains a polar head group composed of phosphocholine or phosphoethanolamine.