荧光胆固醇类似物脱氢麦角固醇在模型膜中诱导形成有序液相区。

The fluorescent cholesterol analog dehydroergosterol induces liquid-ordered domains in model membranes.

作者信息

Garvik Olav, Benediktson Peter, Simonsen Adam Cohen, Ipsen John Hjort, Wüstner Daniel

机构信息

MEMPHYS Center for Biomembrane Physics, Department of Chemistry and Physics, University of Southern Denmark, Odense M, Denmark.

出版信息

Chem Phys Lipids. 2009 Jun;159(2):114-8. doi: 10.1016/j.chemphyslip.2009.03.002. Epub 2009 Mar 28.

DOI:10.1016/j.chemphyslip.2009.03.002

PMID:19477318

Abstract

The fluorescent sterol dehydroergosterol (DHE) is often used as a marker for cholesterol in cellular studies. We show by vesicle fluctuation analysis that DHE has a lower ability than cholesterol to stiffen lipid bilayers suggesting less efficient packing with phospholipid acyl chains. Despite this difference, we found by fluorescence and atomic force microscopy, that DHE induces liquid-ordered/-disordered coexistent domains in giant unilamellar vesicles (GUVs) and supported bilayers made of dipalmitoylphosphatidylcholine (DPPC), dioleylphosphatidylcholine (DOPC) and DHE or cholesterol. DHE-induced phases have a height difference of 0.9-1 nm similar as known for cholesterol-containing domains. DHE not only promotes formation of liquid-liquid immiscibility but also shows strong partition preference for the liquid-ordered phase further supporting its suitability as cholesterol probe.

摘要

荧光固醇脱氢麦角固醇（DHE）在细胞研究中常被用作胆固醇的标志物。我们通过囊泡波动分析表明，与胆固醇相比，DHE使脂质双层变硬的能力较低，这表明其与磷脂酰基链的堆积效率较低。尽管存在这种差异，但我们通过荧光和原子力显微镜发现，DHE在由二棕榈酰磷脂酰胆碱（DPPC）、二油酰磷脂酰胆碱（DOPC）以及DHE或胆固醇构成的巨型单层囊泡（GUV）和支撑双层膜中诱导出液相有序/无序共存域。DHE诱导的相具有0.9 - 1纳米的高度差，这与含胆固醇域的已知高度差相似。DHE不仅促进液 - 液不混溶的形成，而且对液相有序相表现出强烈的分配偏好，这进一步支持了其作为胆固醇探针的适用性。