ABCA1-dependent sterol release: sterol molecule specificity and potential membrane domain for HDL biogenesis

Journal of Lipid Research

Shinji Yokoyama¹  Ta-Yuan Chang²  Yoshio Yamauchi³ 

[1] Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan;Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755;To whom correspondence should be addressed.;

关键词: ATP binding cassette transporter A1;    acyl-CoA:cholesterol acyltransferase;    cholesterol/efflux;    cholesterol/trafficking;    high density lipoprotein;    lipid rafts;   

DOI  :  

来源: DOAJ

【 摘 要 】

Mammalian cells synthesize various sterol molecules, including the C30 sterol, lanosterol, as cholesterol precursors in the endoplasmic reticulum. The build-up of precursor sterols, including lanosterol, displays cellular toxicity. Precursor sterols are found in plasma HDL. How these structurally different sterols are released from cells is poorly understood. Here, we show that newly synthesized precursor sterols arriving at the plasma membrane (PM) are removed by extracellular apoA-I in a manner dependent on ABCA1, a key macromolecule for HDL biogenesis. Analysis of sterol molecules by GC-MS and tracing the fate of radiolabeled acetate-derived sterols in normal and mutant Niemann-Pick type C cells reveal that ABCA1 prefers newly synthesized sterols, especially lanosterol, as the substrates before they are internalized from the PM. We also show that ABCA1 resides in a cholesterol-rich membrane domain resistant to the mild detergent, Brij 98. Blocking ACAT activity increases the cholesterol contents of this domain. Newly synthesized C29/C30 sterols are transiently enriched within this domain, but rapidly disappear from this domain with a half-life of less than 1 h. Our work shows that substantial amounts of precursor sterols are transported to a certain PM domain and are removed by the ABCA1-dependent pathway.

【 授权许可】

Unknown