Format

Send to

Choose Destination
J Lipid Res. 2004 May;45(5):849-58. Epub 2004 Feb 16.

Apolipoprotein A-II regulates HDL stability and affects hepatic lipase association and activity.

Author information

1
Lipoproteins and Atherosclerosis Research Group, University of Ottawa Heart Institute, Ottawa, Ontario, Canada K1Y 4W7.

Abstract

The effect of apolipoprotein A-II (apoA-II) on the structure and stability of HDL has been investigated in reconstituted HDL particles. Purified human apoA-II was incorporated into sonicated, spherical LpA-I particles containing apoA-I, phospholipids, and various amounts of triacylglycerol (TG), diacylglycerol (DG), and/or free cholesterol. Although the addition of PC to apoA-I reduces the thermodynamic stability (free energy of denaturation) of its alpha-helices, PC has the opposite effect on apoA-II and significantly increases its helical stability. Similarly, substitution of apoA-I with various amounts of apoA-II significantly increases the thermodynamic stability of the particle alpha-helical structure. ApoA-II also increases the size and net negative charge of the lipoprotein particles. ApoA-II directly affects apoA-I conformation and increases the immunoreactivity of epitopes in the N and C termini of apoA-I but decreases the exposure of central domains in the molecule (residues 98-186). ApoA-II appears to increase HL association with HDL and inhibits lipid hydrolysis. ApoA-II mildly inhibits PC hydrolysis in TG-enriched particles but significantly inhibits DG hydrolysis in DG-rich LpA-I. In addition, apoA-II enhances the ability of reconstituted LpA-I particles to inhibit VLDL-TG hydrolysis by HL. Therefore, apoA-II affects both the structure and the dynamic behavior of HDL particles and selectively modifies lipid metabolism.

PMID:
14967812
DOI:
10.1194/jlr.M300431-JLR200
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center