Charged giant unilamellar vesicles prepared by electroformation exhibit nanotubes and transbilayer lipid asymmetry.
Charged giant unilamellar vesicles prepared by electroformation exhibit nanotubes and transbilayer lipid asymmetry.
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DOI：
10.1038/s41598-018-30286-z
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发表时间：
2018-08-07
影响因子：
4.6
通讯作者：
Dimova R
中科院分区：
文献类型：
--
作者：
Steinkühler J;De Tillieux P;Knorr RL;Lipowsky R;Dimova R
巨型单层囊泡（GUVs）作为一种研究膜结构、形态和相态的多功能研究工具，越来越受到人们的重视。在这些研究中，GUV的制备通常通过外部施加的电场来增强，这一过程称为电形成。我们发现，在渗透通货紧缩时，由带电和中性脂质电形成的guv表现出向内指向的脂质纳米管，表明膜的负自发曲率。通过猝灭带电脂质的荧光模拟物、zeta电位测量和脂质标记物膜联蛋白A5实验，我们发现电形成的guv在双层小叶上表现出不对称的脂质分布。在室温下电铸guv储存一天后，或者在电铸过程中施加更高的电压和温度，这种不对称性就会消失。具有相同脂质组成但通过凝胶辅助肿胀生长的guv不表现出不对称的脂质分布。我们讨论了脂质不对称产生和松弛的可能机制，以及使用电形成囊泡进行研究的意义。观察到的效应允许控制脂质双分子层小叶的分子组装。这里报道的小泡管状是一个无蛋白膜重塑的例子，是由小叶之间的组成脂质不对称引起的。
Giant unilamellar vesicles (GUVs) are increasingly used as a versatile research tool to investigate membrane structure, morphology and phase state. In these studies, GUV preparation is typically enhanced by an externally applied electric field, a process called electroformation. We find that upon osmotic deflation, GUVs electroformed from charged and neutral lipids exhibit inward pointing lipid nanotubes, suggesting negative spontaneous curvature of the membrane. By quenching a fluorescent analog of the charged lipid, zeta potential measurements and experiments with the lipid marker annexin A5, we show that electroformed GUVs exhibit an asymmetric lipid distribution across the bilayer leaflets. The asymmetry is lost either after storing electroformed GUVs at room temperature for one day or by applying higher voltages and temperatures during electroformation. GUVs having the same lipid composition but grown via gel-assisted swelling do not show asymmetric lipid distribution. We discuss possible mechanisms for the generation and relaxation of lipid asymmetry, as well as implications for studies using electroformed vesicles. The observed effects allow to control the molecular assembly of lipid bilayer leaflets. Vesicle tubulation as reported here is an example of protein-free reshaping of membranes and is caused by compositional lipid asymmetry between leaflets.
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影响因子：
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