The low density lipoprotein (LDL) receptor is a key protein for maintaining cellular cholesterol homeostasis by binding cholesterol-rich lipoproteins through their apoB and apoE apoproteins. The LDL receptor is a transmembrane glycoprotein of Mr ;115 kDa; based on its primary sequence, five distinct structural domains have been identified (Yamamoto, T., Davis, C. G., Brown, M. S., Schneider, W....