Ions Modulate Stress-Induced Nanotexture in Supported Fluid Lipid Bilayers.
Ions Modulate Stress-Induced Nanotexture in Supported Fluid Lipid Bilayers.
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离子在受支持的流体脂质双层中调节应力诱导的纳米纹状体。
DOI：
10.1016/j.bpj.2017.05.049
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发表时间：
2017-07-25
影响因子：
3.4
通讯作者：
Voïtchovsky K
中科院分区：
文献类型：
--
作者：
Piantanida L;Bolt HL;Rozatian N;Cobb SL;Voïtchovsky K
大多数质膜包含大量不同的分子，包括脂质和蛋白质。在标准的流体镶嵌模型中，膜功能受蛋白质的影响，而脂质在很大程度上是被动的，并且仅在膜内聚中起作用。在这里，我们表明，使用支持的1，2-dioleoyl-sn-glycero-3-phosphocholine脂质双层在不同的盐水溶液中，离子可以局部诱导有序的脂质分子内，否则流体双层时，后者是支持的。这种纳米有序表现出一个特征的长度尺度为20 nm，并清楚地表明，当机械应力施加到膜。原子力显微镜（AFM）测量在含有NaCl，KCl，CaCl 2，和Tris缓冲液的水溶液中的效果的幅度是强烈的离子特异性，与Ca 2+和Tris，分别促进和减少应力诱导的纳米纹理的膜。原子力显微镜的结果补充荧光恢复后的光漂白实验，揭示了分子纳米有序的趋势和双层内的扩散系数之间的负相关性。其他脂质和在不同温度下的控制AFM实验支持这一假设，即纳米纹理是由可逆的，局部凝胶状固化的膜。这些结果表明，支持的流体磷脂双层在纳米尺度上是不均匀的，但特定的离子能够局部改变分子的组织和流动性，并在空间上调节膜的性质在20 nm的长度尺度。为了说明这一点，使用AFM跟踪膜穿透抗菌肽Temporin L在不同溶液中的吸附。结果证实，肽不随机吸收，但遵循离子诱导的膜的空间调制。我们的研究结果表明，当与细胞骨架等支持物接触时，离子效应对被动调节生物膜的局部性质具有显着影响。
Most plasma membranes comprise a large number of different molecules including lipids and proteins. In the standard fluid mosaic model, the membrane function is effected by proteins whereas lipids are largely passive and serve solely in the membrane cohesion. Here we show, using supported 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayers in different saline solutions, that ions can locally induce ordering of the lipid molecules within the otherwise fluid bilayer when the latter is supported. This nanoordering exhibits a characteristic length scale of ∼20 nm, and manifests itself clearly when mechanical stress is applied to the membrane. Atomic force microscopy (AFM) measurements in aqueous solutions containing NaCl, KCl, CaCl2, and Tris buffer show that the magnitude of the effect is strongly ion-specific, with Ca2+ and Tris, respectively, promoting and reducing stress-induced nanotexturing of the membrane. The AFM results are complemented by fluorescence recovery after photobleaching experiments, which reveal an inverse correlation between the tendency for molecular nanoordering and the diffusion coefficient within the bilayer. Control AFM experiments on other lipids and at different temperatures support the hypothesis that the nanotexturing is induced by reversible, localized gel-like solidification of the membrane. These results suggest that supported fluid phospholipid bilayers are not homogenous at the nanoscale, but specific ions are able to locally alter molecular organization and mobility, and spatially modulate the membrane’s properties on a length scale of ∼20 nm. To illustrate this point, AFM was used to follow the adsorption of the membrane-penetrating antimicrobial peptide Temporin L in different solutions. The results confirm that the peptides do not absorb randomly, but follow the ion-induced spatial modulation of the membrane. Our results suggest that ionic effects have a significant impact for passively modulating the local properties of biological membranes, when in contact with a support such as the cytoskeleton.
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影响因子：
3.4
作者：
Chiantia, Salvatore;London, Erwin
通讯作者：
London, Erwin
影响因子：
5.8
作者：
Dekkiche, F.;Corneci, M. C.;Rieu, J. -P.
通讯作者：
Rieu, J. -P.
影响因子：
3.4
作者：
Dietrich, C;Bagatolli, LA;Gratton, E
通讯作者：
Gratton, E
DOI：
10.1073/pnas.1605259113
发表时间：
2016-08-30
影响因子：
11.1
作者：
Bradley, Ryan P.;Radhakrishnan, Ravi
通讯作者：
Radhakrishnan, Ravi
影响因子：
3.9
作者：
Bouvrais, Helene;Duelund, Lars;Ipsen, John H.
通讯作者：
Ipsen, John H.