Apolipoprotein M: structure and function

Lipoproteins in blood play an important physiological role transporting cholesterol, lipids and lipid-soluble substances to the different organs of the body. Diseases such as atherosclerosis, cardiovascular disease and stroke are associated with defects in lipoprotein metabolism. For many years, intense research has focused on the role of cholesterol in development of atherosclerosis. Cholesterol is transported in both LDL and HDL; increased concentrations of LDL-C are associated with atherosclerosis, whereas high HDL-C is considered to be protective against development of atherosclerosis. Apolipoproteins Al and B are the major proteins of HDL and LDL, respectively. In HDL, a large number of additional proteins with important functions have been identified. A late addition to the list of HDL-associated proteins is apoM, the structure and function of which are the topic of this review.