Angiopoietin-like 3, also known as ANGPTL3, is a protein that in humans is encoded by the ANGPTL3 gene. [5] [6]
The protein encoded by this gene is a member of the angiopoietin-like family of secreted factors. It is expressed predominantly in the liver, and has the characteristic structure of angiopoietins, consisting of a signal peptide, N-terminal coiled-coil domain, and the C-terminal fibrinogen (FBN)-like domain. The FBN-like domain in angiopoietin-like 3 protein was shown to bind alpha-5/beta-3 integrins, and this binding induced endothelial cell adhesion and migration. This protein may also play a role in the regulation of angiogenesis. [5]
Angptl3 also acts as dual inhibitor of lipoprotein lipase (LPL) and endothelial lipase (EL), [7] thereby increasing plasma triglyceride, LDL cholesterol and HDL cholesterol in mice and humans. [7]
ANGPTL3 inhibits endothelial lipase hydrolysis of HDL-phospholipid (PL), thereby increasing HDL-PL levels.[ citation needed ] Circulating PL-rich HDL particles have high cholesterol efflux abilities.[ citation needed ]
Angptl3 plays a major role in promoting uptake of circulating triglycerides into white adipose tissue in the fed state, [8] likely through activation by Angptl8, a feeding-induced hepatokine, [9] [10] to inhibit postprandial LPL activity in cardiac and skeletal muscles, [11] as suggested by the ANGPTL3-4-8 model. [12]
In human, ANGPTL3 is a determinant factor of HDL level and positively correlates with plasma HDL cholesterol.[ citation needed ]
In humans with genetic loss-of-function variants in one copy of ANGPTL3, the serum LDL-C levels are reduced. In those with loss-of-function variants in both copies of ANGPTL3, low LDL-C, low HDL-C, and low triglycerides are seen ("familial combined hypolipidemia"). [13]