Processive capping by formin suggests a force-driven mechanism of actin polymerization.
Processive capping by formin suggests a force-driven mechanism of actin polymerization.
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DOI：
10.1083/jcb.200410017
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发表时间：
2004-12-20
影响因子：
7.8
通讯作者：
Bershadsky, Alexander D
中科院分区：
文献类型：
--
作者：
Kozlov, Michael M;Bershadsky, Alexander D
肌动蛋白聚合的调节对细胞功能至关重要。在这里，我们预测了一种新的现象-由formin家族蛋白介导的肌动蛋白丝的力驱动聚合。Formins定位于肌动蛋白丝的倒刺端，但是，与标准的封盖蛋白相反，它允许肌动蛋白在倒刺方向聚合。首先，我们证明了这种“漏盖”的机制可以从双胍分子的弹性来理解。其次，我们证明了如果拉力通过漏帽作用在丝端，弹性应力可以驱动肌动蛋白聚合。我们估计，约3.4 pN的中等拉力足以将倒钩端聚合所需的临界肌动蛋白浓度降低一个数量级。此外，拉力增加了聚合速率。提出的力驱动聚合的机制可能是各种细胞机械传感装置的关键因素。
Regulation of actin polymerization is essential for cell functioning. Here, we predict a novel phenomenon—the force-driven polymerization of actin filaments mediated by proteins of the formin family. Formins localize to the barbed ends of actin filaments, but, in contrast to the standard capping proteins, allow for actin polymerization in the barbed direction. First, we show that the mechanism of such “leaky capping” can be understood in terms of the elasticity of the formin molecules. Second, we demonstrate that if a pulling force acts on the filament end via the leaky cap, the elastic stresses can drive actin polymerization. We estimate that a moderate pulling force of ∼3.4 pN is sufficient to reduce the critical actin concentration required for barbed end polymerization by an order of magnitude. Furthermore, the pulling force increases the polymerization rate. The suggested mechanism of force-driven polymerization could be a key element in a variety of cellular mechanosensing devices.