BackgroundAngiopoietins have two domains: an N-terminal coiled-coil domain that mediates homo-oligomerization, and a C-terminal fibrinogen like domain that binds Tie2. Angiopoietins bind Tie2 receptor tyrosine kinase and regulate angiogenesis and the preservation of vascular integrity and permeability. Angiopoietin-like proteins (ANGPTLs) are structurally similar to angiopoietin. Seven ANGPTLs, ANGPTL1–7, exhibit an N-terminal coiled-coil domain and a C-terminal fibrinogen like domain. Only ANGPTL8, which is homologous to ANGPTL3’s N-terminal domain, lacks a C-terminal fibrinogen-like domain. Angiopoietin-like proteins (ANGPTLs) are a family containing groups of proteins, which are structurally like the angiopoietins family (ANG). Only eight ANGPTLs had been discovered, from ANGPTL1 to ANGPTL8. Interestingly, some ANGPTL proteins have multibiological properties and play functional roles in lipid metabolism, inflammation, hematopoietic stem cell activity, and cancer cell invasion. Angiopoietin-like protein 3 (ANGPTL3), also known as angiopoietin-5, firstly discovered in 1999, which is closely related to the disorder of lipid metabolism. The encoded ANGPTL3 protein belongs to a kind of secreted protein factors with multiple functions such as promotion of neovascularization and hyperlipidemia. Generally, Human ANGPTL3 is a 460-amino-acid polypeptide (molecular mass of 70 kDa) with the characteristic structure of angiopoietins. ANGPTL3 gene locates on human chromosome 1 (1p31.1-p22.3) and includes seven exons and six introns. In addition, ANGPTL3 is mainly expressed in the liver. ANGPTL3 levels are significantly increased in non alcoholic steatohepatitis (NASH) patients, which may be associated with insulin resistance in NASH patients. Host lipid metabolism reprogramming is essential for hepatitis C virus (HCV) infection and progression to severe liver disease. Angiopoietin-like protein-3 (ANGPTL-3) regulates the clearance of plasma lipids by inhibiting cellular lipase activity and possesses emerging roles in tumorigenesis.