Cellular signalling by lipoprotein receptors

Lipoprotein receptors are commonly thought merely to mediate the internaliz ation of lipoprotein particles or the exchange of lipids at the cell surfac e. Recent findings have now implicated these multifunctional receptors in c ellular signalling mechanisms that extend beyond simple ligand endocytosis. By mediating the cellular uptake of lipophilic vitamins and hormones, mega lin, a member of the LDL receptor gene family, regulates critical hormonal and metabolic processes. Other members of the LDL receptor family interact with cytoplasmic adaptor and scaffold proteins, which allows them to transm it signals directly across the plasma membrane of the target cell. This she ds a new light on the emerging roles of lipoprotein receptors in pathologic disease processes such as Alzheimer's disease. Curr Opin Lipidol 11:161-16 6. (C) 2000 Lippincott Williams & Wilkins.