It is thought to act primarily in reverse cholesterol transport[4] and intestinal lipid absorption via chylomicron assembly and secretion.

Recent findings with apoA1 and apoE suggest that the tertiary structures of these two members of the human exchangeable apolipoprotein gene family are related.

[8] The three-dimensional structure of the LDL receptor-binding domain of apoE indicates that the protein forms an unusually elongated four-helix bundle that may be stabilised by a tightly packed hydrophobic core that includes leucine zipper-type interactions and by numerous salt bridges on the mostly charged surface.

Basic amino acids important for LDL receptor binding are clustered into a surface patch on one long helix.

[16] Beyond vertebrates, proteins similar to the exchangeable ApoA/C/E and the nonexchangable Apo-B are found in a wide range of animals and choanoflagellates.

Apolipoprotein synthesis in the liver is controlled by a host of factors, including dietary composition, hormones (insulin, glucagon, thyroxin, estrogens, androgens), alcohol intake, and various drugs (statins, niacin, and fibric acids).

ApoC1 level increases in neuropathic pain and fibromyalgia patients which suggest it plays an important role in occurrence of these conditions.

[19] ApoD level increases in nervous system with a large number of neurologic disorders inclusive of Alzheimer's disease, schizophrenia, and stroke.