APOA4 - Function

Function

The primary translation product of the APOA4 gene is a 396-residue preprotein, which undergoes proteolytic processing to yield apo A-IV, a 376-reside mature O-linked glycoprotein. In most mammals, including humans, apo A-IV synthesis is confined to the intestine; however in mice and rats hepatic synthesis also occurs. Apo A-IV is secreted into circulation on the surface of newly synthesized chylomicron particles. Intestinal fat absorption dramatically increases the synthesis and secretion of apo A-IV. Although its primary function in human lipid metabolism has not been established, apo A-IV has been found to: 1) activate lecithin-cholesterol acyltransferase and cholesterylester transfer protein in vitro; 2) play a role in the regulation of appetite and satiety in rodent models; 3) display anti-oxidant and anti-atherogenic properties in vitro and in rodent models; 4) modulate the efficiency of enterocyte and hepatic transcellular lipid transport in vitro. Human apo A-IV deficiency has not been reported.