The central type Y amphipathic α-helices of apolipoprotein AI are involved in the mobilization of intracellular cholesterol depots
- 作者：Marina C. Gonzalez ; Juan D. Toledo ; M. Alej ; ra Tricerri ; Horacio A. Garda
- 关键词：Apolipoprotein AI ; Cholesterol efflux ; Chinese hamster ovary cells ; Intracellular cholesterol mobilization ; Mutants ; Reverse cholesterol transport ; Reconstituted high density lipoprotein
- 刊名：Archives of Biochemistry and Biophysics
- 出版年：2008
- 期刊代码：116_00039861
- 类别：ch
- 出版时间：1 May 2008
- 卷：473
- 期：1
- 页码：34-41
- 文件大小：510 K
摘要
We studied the role of a central domain of human apolipoprotein AI (apoAI) in cholesterol mobilization and removal from cells. In order to check different protein conformations, we tested different sized and cholesterol-content reconstituted apoAI particles (rHDL). Meanwhile cholesterol-free discs were active to induce mobilization, only small cholesterol-containing rHDL were active. To test the influence of a central domain in such events, we used two apoAI variants: one, with its central Y helix pair replaced by the C-terminal domain, and the other having a lysine deleted in central region. The helix-swapping variant decrease the cholesterol pool available to acyl-CoA cholesterol acyl transferase and increase mobilization of newly synthesized cholesterol. Instead, the deletion mutant had no effect on both events. We conclude that the central domain of apoAI is involved in cholesterol cell traffic and solubilization, and that a Y-type charge distribution in polar face may be required, as well as a correct helices-polar face orientation.