ApoCIV

ApoCIV, short for apolipoprotein C-IV, is a small protein that belongs to the apolipoprotein C family. In humans, the APOC4 gene encodes this protein. ApoCIV associates with circulating lipoproteins, including chylomicrons, very-low-density lipoproteins (VLDL), and, to a lesser extent, high-density lipoprotein (HDL). The protein is secreted into plasma primarily by the liver and, to a lesser extent, the intestine.

Functionally, ApoCIV is thought to participate in triglyceride-rich lipoprotein metabolism. It may influence lipoprotein lipase activity and hepatic uptake of remnant particles, but its exact role is not well defined. Its distribution on lipoprotein surfaces suggests a potential involvement in particle remodeling and lipoprotein interactions, although experimental data are limited compared with other apolipoproteins.

Genetic and clinical significance remain areas of active study. Variants in APOC4 have been examined for associations with plasma lipid traits in some populations, with results that are not yet consistent or conclusive. Because ApoCIV is among the less-characterized apolipoproteins, its utility as a biomarker or therapeutic target is uncertain. Ongoing research aims to clarify its regulation, tissue expression, and interactions with other apolipoproteins and lipid-metabolizing enzymes as part of a broader effort to understand lipid metabolism and related diseases.