Chronic hepatitis C virus infection and lipoprotein metabolism

Table 2 Properties and functions of major apolipoproteins

Name	Molecular weight (Da)	Origin	Lipoprotein association	Principal function
apo A-I	28016	Hepatocyte	HDL>>CM	Cofactor of LCAT
		Intestinal epithelial cell		Prostacyclin stabilizer
				Ligand of SR-B1
apo A-II	17414	Hepatocyte	HDL	Inhibits LCAT
		Intestinal epithelial cell		Inhibits HL
apo A-IV	31570	Intestinal epithelial cell	CM	(Activates LCAT?)
		(hepatocyte?)		(Activates CETP?)
apo B-48	241000	Intestinal epithelial cell (splicing variant of apo B-100)	CM and CM remnant	Formation of CM particle
apo B-100	545000	Hepatocyte	VLDL, IDL, and LDL	Formation of VLDL/LDL particle
				Ligand of LDL receptor
apo C-I	6600	Hepatocyte	CM, VLDL, IDL, and HDL	Inhibits CETP by altering the electric charge of HDL
apo C-II	8800	Hepatocyte	CM, VLDL, IDL, and HDL	Cofactor of LPL
apo C-III	8750	Hepatocyte	CM, VLDL, IDL, and HDL	Inhibits LPL and HL
				Promotes assembly and secretion of VLDL
apo C-IV		Hepatocyte	CM, VLDL, IDL, and HDL	Not specified
apo E	34100	Hepatocyte	CM, CM remnant, VLDL, IDL and HDL	Ligand of LDL receptor/LDL receptor-related protein
		Macrophage		Binds to HSPGs

HDLs: High-density lipoproteins; CMs: Chylomicrons; IDLs: Intermediate-density lipoproteins; VLDL: Very-low-density lipoprotein; LDLs: Low-density lipoproteins; HSPGs: Heparan sulfate proteoglycans.