During mitochondrial fission, key molecular and cellular factors assemble on the outer mitochondrial membrane, where they coordinate to generate constriction. Constriction sites can eventually divide, or reverse upon disassembly of the machinery. However, a role for membrane tension in mitochondrial fission, although speculated, has remained undefined. We captured the dynamics of constricting mitochondria in mammalian cells using live-cell structured illumination microscopy (SIM). By analyzing the diameters of tubules that emerge from mitochondria and implementing a fluorescence lifetime-based mitochondrial membrane tension sensor, we discovered that mitochondria are indeed under tension. Under perturbations that reduce mitochondrial tension, constrictions initiate at the same rate, but are less likely to divide. We propose a model based on our estimates of mitochondrial membrane tension and bending energy in living cells which accounts for the observed probability distribution for mitochondrial constrictions to divide.

中文翻译：

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线粒体膜张力控制裂变

在线粒体裂变期间，关键的分子和细胞因子聚集在线粒体外膜上，在那里它们协调产生收缩。收缩部位最终可能会分开，或者在拆卸机器时会逆转。然而，尽管推测，膜张力在线粒体裂变中的作用仍不确定。我们使用活细胞结构照明显微镜（SIM）捕获了哺乳动物细胞中线粒体的收缩动力学。通过分析来自线粒体的细管直径并实现基于荧光寿命的线粒体膜张力传感器，我们发现线粒体确实处于张力下。在减少线粒体张力的扰动下，收缩开始的速率相同，但分裂的可能性较小。