Relaxation of Loaded ESCRT-III Spiral Springs Drives Membrane Deformation.
Relaxation of Loaded ESCRT-III Spiral Springs Drives Membrane Deformation.
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DOI：
10.1016/j.cell.2015.10.017
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发表时间：
2015-11-05
期刊：
影响因子：
64.5
通讯作者：
Roux A
中科院分区：
文献类型：
--
作者：
Chiaruttini N;Redondo-Morata L;Colom A;Humbert F;Lenz M;Scheuring S;Roux A
ESCRT-III是许多细胞过程中脂质膜重塑所必需的，从脱落到病毒出芽和多囊泡体生物发生。然而，ESCRT-III聚合如何产生膜曲率仍然存在争议。在这里，我们表明，SnF 7，ESCRT-III的主要成分，聚合成螺旋在脂质双层的表面。当覆盖整个膜表面时，这些螺旋在密集堆积时停止生长：它们具有多边形形状，这表明侧向压缩可以使它们变形。我们推断SnF 7螺旋可以起到螺旋弹簧的作用。通过测量SnF 7纤维的聚合能和刚性，我们发现它们在受限区域生长时会变形。此外，我们观察到压缩的Snf 7螺旋的弹性膨胀在膜两侧之间产生了面积差，从而产生了曲率。这种类似弹簧的活动是ESCRT-III介导膜变形和裂变的驱动力的基础。Snf 7形成高度柔性的细丝，自发卷曲Snf 7细丝在脂质膜表面形成螺旋Snf 7螺旋是弹簧，因为它们可以在横向压缩下变形压缩Snf 7螺旋的松弛导致膜变形ESCRT-III膜裂变机制的一个组成部分自组织成螺旋弹簧，当释放时触发膜变形。
ESCRT-III is required for lipid membrane remodeling in many cellular processes, from abscission to viral budding and multi-vesicular body biogenesis. However, how ESCRT-III polymerization generates membrane curvature remains debated. Here, we show that Snf7, the main component of ESCRT-III, polymerizes into spirals at the surface of lipid bilayers. When covering the entire membrane surface, these spirals stopped growing when densely packed: they had a polygonal shape, suggesting that lateral compression could deform them. We reasoned that Snf7 spirals could function as spiral springs. By measuring the polymerization energy and the rigidity of Snf7 filaments, we showed that they were deformed while growing in a confined area. Furthermore, we observed that the elastic expansion of compressed Snf7 spirals generated an area difference between the two sides of the membrane and thus curvature. This spring-like activity underlies the driving force by which ESCRT-III could mediate membrane deformation and fission. Snf7 forms highly flexible filaments that spontaneously curl Snf7 filaments forms spirals at the surface of lipid membranes Snf7 spirals are springs as they can deform under lateral compression Relaxation of compressed Snf7 spirals leads to membrane deformation A component of the ESCRT-III membrane fission machinery self-organizes into spiral springs that trigger membrane deformation when released.