Fig. 3

Overview of the cholesterol efflux and storage system. Excess intracellular cholesterol is stored as lipid droplets in cytosol or transported out of the cell via ABC transporter here represented by ABCA1 and ABCG1. Lecithin-Cholesterol Acyltransferase (LCAT) esterifies free cholesterol into cholesteryl ester on the surface of the HDL forming HDL2 and HDL3 which are modified forms of HDL with decreasing amount of cholesterol on their surface. HDL particles are transported to the liver for excretion through the intestine. Cholesterol Acyltransferase 1 (ACAT1/SOAT) esterifies intracellular free cholesterol to be stored in lipid droplets. When stored cholesterol is needed, Neutral Lipid Ester Hydrolase (NEH) releases stored lipids and cholesterol for cellular use