APOC4 (Apolipoprotein C-IV): APOC4 is a protein belonging to the apolipoprotein family that plays a key role in lipid metabolism and transport. It helps regulate triglyceride-rich lipoprotein particles and influences how lipoproteins interact with their receptors and lipid transfer proteins. APOC4 is found in several plasma lipoprotein fractions, including very low-density lipoproteins (VLDL) and high-density lipoproteins (HDL). Its involvement in lipid metabolism links it to cardiovascular health, with dysregulation or genetic variations potentially affecting lipid levels and contributing to atherosclerosis, coronary artery disease, and other lipid disorders.