Plasma Lipid Transfer Proteins

The plasma lipid transfer proteins mediate the transfer and exchange of phospholipids and neutral lipids between the plasma lipoproteins. The cholesteryl ester transfer protein (CETP) and the phospholipid transfer protein (PLTP) are members of the lipid transfer/lipopolysaccharide binding gene family. The CETP contains binding sites for cholesteryl ester and triglycerides and probably acts by a carrier-mediated mechanism. The CETP mediates catabolism of HDL cholesteryl esters, with secondary decreases in HDL size and protein content. The CETP plays a central role in reverse cholesterol transport i.e. the centripetal movement of cholesterol from the periphery back to the liver. CETP gene expression is upregulated in response to increased dietary cholesterol or endogenous hypercholesterolemia. Although CETP reduces HDL levels, its role in reverse cholesterol transport suggests a dominant anti-atherogenic action in vivo.