Human Apolipoprotein C-I (APOC1) Protein

Background

APOC1 is a small protein mainly associated with high-density lipoproteins (HDL), and to a lesser extent with very-low-density lipoproteins (VLDL) and chylomicrons. It is synthesized primarily in the liver and plays a crucial role in lipid metabolism by modulating the activity of lipoprotein lipase (LPL) and cholesteryl ester transfer protein (CETP). APOC1 inhibits CETP, thereby reducing the transfer of cholesteryl esters from HDL to LDL and VLDL, which promotes HDL cholesterol levels. It also regulates triglyceride metabolism by modulating lipolytic activity, thereby influencing plasma lipid homeostasis. Elevated APOC1 levels have been associated with dyslipidemia, atherosclerosis, and an increased risk of cardiovascular diseases. It may also play a role in inflammatory responses and has been linked to neurodegenerative diseases like Alzheimer’s disease, where it interacts with amyloid-beta peptides. Research indicates APOC1 has a protective role in the reverse cholesterol transport pathway, facilitating cholesterol efflux from peripheral tissues back to the liver. Genetic variations in the APOC1 gene influence plasma lipid profiles and susceptibility to metabolic disorders, including obesity and insulin resistance.