Lipid rafts: new tools and a new component.

Lipid rafts are liquid ordered membrane domains enriched with sphingolipids and cholesterol. After 20 years since the proposal of the original concept, the structure and function of lipid rafts are still obscure. Recently new tools to study lipid rafts have been developed. Lysenin is a sphingomyelin binding protein that specifically recognizes the lipid clusters. Poly(ethyleneglycol)-derivatized cholesterol ether (PEG-Chol) is a non-toxic cholesterol probe. These probes have revealed the heterogeneity of lipid rafts. The heterogeneity of lipid rafts is further supported by the discovery of a new lipid component, phosphatidylglucoside. Metabolic inhibitors are another useful tool. Sulfamisterin is a new addition to the serine palmitoyltransferase inhibitors. Recent findings have uncovered a previously unrecognized activity of a glycosphingolipid synthesis inhibitor, D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP).