Chemical Engineering Department, Columbia University, New York, New York.
Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania.
Traffic. 2018 May;19(5):328-335. doi: 10.1111/tra.12555. Epub 2018 Mar 25.
It is now widely accepted that dynamin-mediated fission is a fundamentally mechanical process: dynamin undergoes a GTP-dependent conformational change, constricting the neck between two compartments, somehow inducing their fission. However, the exact connection between dynamin's conformational change and the scission of the neck is still unclear. In this paper, we re-evaluate the suggestion that a change in the pitch or radius of dynamin's helical geometry drives the lipid bilayer through a mechanical instability, similar to a well-known phenomenon occurring in soap films. We find that, contrary to previous claims, there is no such instability. This lends credence to an alternative model, in which dynamin drives the membrane up an energy barrier, allowing thermal fluctuations to take it into the hemifission state.
现在人们普遍认为，动力蛋白介导的分裂是一个基本的机械过程：动力蛋白经历 GTP 依赖性构象变化，在两个隔室之间的颈部收缩，以某种方式诱导它们分裂。然而，动力蛋白构象变化和颈部分裂之间的确切联系仍然不清楚。在本文中，我们重新评估了这样一种观点，即动力蛋白螺旋几何形状的 pitch 或半径的变化通过机械不稳定性驱动脂质双层，类似于肥皂膜中发生的一种众所周知的现象。我们发现，与之前的说法相反，不存在这种不稳定性。这为另一种模型提供了可信度，即动力蛋白驱动膜越过一个能量势垒，允许热涨落将其带入半分裂状态。
