Khosravanizadeh Amir, Dmitrieff Serge
Institut Jacques Monod, Université Paris Cité, Paris, France.
J R Soc Interface. 2025 May;22(226):20240859. doi: 10.1098/rsif.2024.0859. Epub 2025 May 7.
We used numerical simulations to investigate how properties of motor proteins control the dynamical behaviour of driven flexible filaments. A filament on top of a patch of anchored motor proteins is pinned at one end, a setup referred to as a spiral gliding assay. There exists a variety of motor proteins with different properties. We found that when these properties are changed, this system generally can show three different regimes: (i) fluctuation, where the filament undergoes random fluctuations because the motors are unable to bend it, (ii) rotation, in which the filament bends and then moves continuously in one direction, and (iii) beating, where the filament rotation direction changes over time. We found that the transition between fluctuation and rotation occurs when motors exert a force sufficient to buckle the filament. The threshold force coincides with the second buckling mode of a filament undergoing a continuously distributed load. Moreover, we showed that when motors near the pinning point work close to their stall force, they cause dynamic clamping, leading to the beating regime. Rather than being imposed by experimental conditions, this clamping is transient and results from the coupling between filament mechanics and the collective behaviour of motors.
我们使用数值模拟来研究运动蛋白的特性如何控制驱动柔性细丝的动力学行为。在一片固定的运动蛋白上方的细丝一端被固定，这种设置被称为螺旋滑动试验。存在多种具有不同特性的运动蛋白。我们发现，当这些特性发生变化时，该系统通常会呈现出三种不同的状态：（i）波动状态，细丝会发生随机波动，因为运动蛋白无法使其弯曲；（ii）旋转状态，细丝弯曲然后沿一个方向持续移动；（iii）摆动状态，细丝的旋转方向随时间变化。我们发现，当运动蛋白施加的力足以使细丝弯曲时，波动状态和旋转状态之间会发生转变。该阈值力与承受连续分布载荷的细丝的第二屈曲模式一致。此外，我们还表明，当固定点附近的运动蛋白在接近其失速力的状态下工作时，它们会导致动态钳制，从而产生摆动状态。这种钳制不是由实验条件强加的，而是瞬时的，是细丝力学与运动蛋白集体行为之间耦合的结果。
