Background of the antigen
Apolipoproteins are protein components of plasma lipoproteins. ApoM (Apolipoprotein M), also known as protein G3a, is a member of the Lipocalin family of proteins. ApoM is exclusively expressed in kidney tubular epithelial cells and liver hepatocytes. Mature ApoM retains its signal peptide, which acts as a hydrophobic anchor, and contains a structurally conserved eight stranded antiparallel ∫ barrel which binds retinol and retinoic acid. ApoM may play a key role in reverse cholesterol transport. It mainly associates with high density lipoprotein (HDL) and to a lesser extent with triglyceride-rich lipoprotein (TGRLP) and low-density lipoprotein (LDL). ApoM is important for the pre∫-HDL formation. Pre∫-HDL is an important acceptor of peripheral cellular cholesterol. The concentration of ApoM in plasma strongly correlates with total cholesterol. Low concentrations of ApoM in plasma is associated with diabetes.
