A mechanical model reveals that non-axisymmetric buckling lowers the energy barrier associated with membrane neck constriction
A mechanical model reveals that non-axisymmetric buckling lowers the energy barrier associated with membrane neck constriction
复制标题
机械模型揭示非轴对称屈曲降低了与膜颈收缩相关的能量势垒
DOI：
10.1039/c9sm01494b
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发表时间：
2020
期刊：
影响因子：
3.4
通讯作者：
Rangamani, P.
中科院分区：
文献类型：
--
作者：
Vasan, R.;Rudraraju, S.;Akamatsu, M.;Garikipati, K.;Rangamani, P.
膜颈的形成对断裂至关重要，正如最近对小管的实验所证明的那样，这可能与位置有关。可以收缩颈部的生物机制的多样性，如动力蛋白、肌动蛋白、escrt和BAR蛋白，以及它们运作的力和挠度的范围，表明收缩过程在功能上是机械的，对生物环境的变化具有很强的适应性。在这项研究中，我们使用了脂质双分子层的力学模型来系统地研究位置、对称约束和螺旋力对膜颈收缩的影响。我们的模型模拟表明，与膜颈收缩相关的能量障碍与位置有关。重要的是，如果对称限制被放宽，那么收缩的能量势垒就会大大降低，膜在较低的强迫参数值下屈曲。我们的模拟还表明，与圆柱形蛋白质相比，螺旋蛋白的收缩进一步降低了颈部形成的能量屏障。这些研究表明，尽管细胞颈部形成的分子机制不同，但收缩的机制自然会导致对称性的丧失，从而降低收缩的能量屏障。
Membrane neck formation is essential for scission, which, as recent experiments on tubules have demonstrated, can be location dependent. The diversity of biological machinery that can constrict a neck such as dynamin, actin, ESCRTs and BAR proteins, and the range of forces and deflection over which they operate, suggest that the constriction process is functionally mechanical and robust to changes in biological environment. In this study, we used a mechanical model of the lipid bilayer to systematically investigate the influence of location, symmetry constraints, and helical forces on membrane neck constriction. Simulations from our model demonstrated that the energy barriers associated with constriction of a membrane neck are location-dependent. Importantly, if symmetry restrictions are relaxed, then the energy barrier for constriction is dramatically lowered and the membrane buckles at lower values of forcing parameters. Our simulations also show that constriction due to helical proteins further reduces the energy barrier for neck formation when compared to cylindrical proteins. These studies establish that despite different molecular mechanisms of neck formation in cells, the mechanics of constriction naturally leads to a loss of symmetry that can lower the energy barrier to constriction.
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