ABC transporters and cholesterol metabolism

ATP-binding cassette (ABC) proteins form a group of highly conserved cellul ar transmembrane transporters. Studies over the past year have implicated A BC transporters in cellular lipid trafficking processes. This notion has re cently been confirmed and extended by the finding that the ABC transporter ABCA1 is a key regulator of high-density lipoprotein (HDL) metabolism and m acrophage targeting to the RES or the vascular wall. Expression of a large number of ABC transporters in monocytes/macrophages and their regulation by cholesterol flux render these transporter molecules potentially critical p layers in chronic inflammatory diseases such as atherosclerosis.