Native Human Apolipoprotein CII/ApoC-II

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

Apolipoprotein CII (ApoC-II) also known as ApoC2 or ApoC II protein is a small protein with a mass of approximately 8.9 kDa. The protein primarily expresses in the liver and secreted into the bloodstream as a component of very low-density lipoproteins (VLDL) and chylomicrons. In terms of structure ApoC-II comprises part of the apolipoprotein family functioning to mediate lipid metabolism by interacting with lipoproteins in the circulatory system.

Biological function summary

ApoC-II plays a critical role in lipid metabolism by activating lipoprotein lipase (LPL) an enzyme that hydrolyzes triglycerides into free fatty acids and glycerol. This protein is essential in the chylomicron and VLDL complex that transports triglycerides from the intestines and liver to peripheral tissues. Through this activation of LPL ApoC-II facilitates the breakdown and clearance of triglyceride-rich lipoproteins from the bloodstream maintaining lipid homeostasis.

Pathways

ApoC-II significantly impacts the lipid metabolism pathway by influencing the catabolism of triglyceride-rich lipoproteins. It therefore plays a role in the lipolytic pathway where it maintains plasma triglyceride levels. Additionally ApoC-II is associated with the LPL pathway with the protein's function closely interacting with other lipoproteins such as ApoC-III which can inhibit LPL activity and modulate the effects of ApoC-II on lipid hydrolysis.

ApoC-II mutations or deficiencies can lead to hyperlipoproteinemia type IB a condition characterized by elevated triglyceride levels due to impaired lipoprotein breakdown. This disorder can result in complications like pancreatitis and cardiovascular disease. Within these disease contexts ApoC-II's interaction with ApoC-III becomes significant as ApoC-III acts as an antagonist to LPL suggesting a balance between these proteins is necessary for maintaining normal lipid metabolism and preventing disorder development.