期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 277, 期 36, 页码 33178-33187出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M204996200
关键词
-
资金
- NHLBI NIH HHS [HL68988, HL45098, HL10398] Funding Source: Medline
The ABCA1 transporter contains two large domains into which many of the genetic mutations in individuals with Tangier disease fall. To investigate the structural requirements for the cellular cholesterol efflux mediated by ABCA1, we have determined the topology of these two domains and generated transporters harboring five naturally occurring missense mutations in them. These mutants, unlike wild type ABCA1, produced little or no apoA-I-stimulated cholesterol efflux when transfected into 293 cells, establishing their causality in Tangier disease. Because all five mutant proteins were well expressed and detectable on the plasma membrane, their interaction with the ABCA1 ligand, apolipoprotein (apo) A-I, was measured using bifunctional cross-linking agents. Four of five mutants had a marked decline in cross-linking to apoA-I, whereas one (W590S) retained full cross-linking activity. Cross-linking of apoA-I was temperature-dependent, rapid in onset, and detectable with both lipid-and water-soluble cross-linking agents. These results suggest that apoA-I-stimulated cholesterol efflux cannot occur without a direct interaction between the apoprotein and critical residues in two extracellular loops of ABCAI. The behavior of the W590S mutant indicates that although binding of apoA-I by ABCA1 may be necessary, it is not sufficient for stimulation of cholesterol efflux.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据