Twist response of actin filaments.
Twist response of actin filaments.
复制标题
肌动蛋白丝的扭曲反应。
DOI：
10.1073/pnas.2208536120
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发表时间：
2023-01-24
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
--
作者：
肌动蛋白丝如何响应机械载荷是理解细胞力产生和机械传感的核心。虽然有共识的肌动蛋白丝的弯曲刚度，报告值的丝扭转刚度变化了近2个数量级。我们使用磁性镊子和流体动力学流动来确定细丝如何响应施加的扭转和拉伸载荷。扭曲导致细丝采用超螺旋构象。拉力抑制超螺旋的形成和丝的碎片。这些观察结果解释了肌球蛋白马达产生的收缩力如何加速细胞中cofilin调节蛋白的细丝切断。肌动蛋白细胞骨架力的产生、感知和适应是由微丝的弯曲和扭曲机制决定的。在这里，我们使用磁性镊子和微流体扭曲和拉动单个肌动蛋白丝，并评估它们对施加载荷的反应。加捻长丝通过采用超螺旋的纤维素而发生弯曲并消散扭转应变。牵拉阻止了丛丝的形成，这导致扭曲的花丝切断。通过对一系列扭转力和拉力的分析，以及对肌动蛋白丝和单个亚基扭转波动的直接观察，得出肌动蛋白丝的扭转持续长度约为10 µm，与弯曲持续长度相似。由cofilin切断的长丝由裸片段和装饰片段之间的边界处的局部扭转应变驱动，并且由低pN拉力加速。这项工作解释了肌球蛋白马达产生的收缩力如何加速丝切割的cofilin和建立一个作用，丝扭曲的肌动蛋白丝的稳定性和装配动力学的调节。
How actin filaments respond to mechanical loads is central to understanding cellular force generation and mechanosensing. While there is consensus on the actin filament bending stiffness, reported values of the filament torsional stiffness vary by almost 2 orders of magnitude. We used magnetic tweezers and hydrodynamic flow to determine how filaments respond to applied twisting and pulling loads. Twisting causes filaments to adopt a supercoil conformation. Pulling forces inhibit supercoil formation and fragment filaments. These observations explain how contractile forces generated by myosin motors accelerate filament severing by cofilin regulatory proteins in cells. Actin cytoskeleton force generation, sensing, and adaptation are dictated by the bending and twisting mechanics of filaments. Here, we use magnetic tweezers and microfluidics to twist and pull individual actin filaments and evaluate their response to applied loads. Twisted filaments bend and dissipate torsional strain by adopting a supercoiled plectoneme. Pulling prevents plectoneme formation, which causes twisted filaments to sever. Analysis over a range of twisting and pulling forces and direct visualization of filament and single subunit twisting fluctuations yield an actin filament torsional persistence length of ~10 µm, similar to the bending persistence length. Filament severing by cofilin is driven by local twist strain at boundaries between bare and decorated segments and is accelerated by low pN pulling forces. This work explains how contractile forces generated by myosin motors accelerate filament severing by cofilin and establishes a role for filament twisting in the regulation of actin filament stability and assembly dynamics.
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影响因子：
3.7
作者：
Graham JS;McCullough BR;Kang H;Elam WA;Cao W;De La Cruz EM
通讯作者：
De La Cruz EM
影响因子：
16
作者：
Andrianantoandro, Ernesto;Pollard, Thomas D.
通讯作者：
Pollard, Thomas D.
影响因子：
64.8
作者：
Fujii, Takashi;Iwane, Atsuko H.;Namba, Keiichi
通讯作者：
Namba, Keiichi
影响因子：
3.4
作者：
De la Cruz, Enrique M.;Martiel, Jean-Louis;Blanchoin, Laurent
通讯作者：
Blanchoin, Laurent
影响因子：
5.6
作者：
Fan, Jun;Saunders, Marissa G.;Haddadian, Esmael J.;Freed, Karl F.;De La Cruz, Enrique M.;Voth, Gregory A.
通讯作者：
Voth, Gregory A.