Rotation-Beating dynamics of a driven flexible filament: role of motor protein properties

TL;DR

This study uses numerical simulations to explore how motor protein properties influence the dynamic regimes of a driven flexible filament, revealing transitions between fluctuation, rotation, and beating behaviors.

Contribution

It demonstrates how specific motor protein parameters control filament dynamics and identifies the conditions leading to different motion regimes, including a novel beating regime.

Findings

Transition from fluctuation to rotation occurs at a buckling threshold

Motors near stall force cause filament beating by acting as a second pin

Filament exhibits three regimes: fluctuation, rotation, beating

Abstract

We have used numerical simulations to investigate how the properties of motor proteins control the dynamical behavior of a driven flexible filament. The filament is pinned at one end and positioned on top of a patch of anchored motor proteins, a setup commonly referred to as a spiral gliding assay. In nature, there is a variety of motor proteins with different properties. In this study, we have investigated the role of detachment rate, detachment force, stall force, and unloaded speed of motors on the dynamical behavior of the filament. We found that this system generally can show three different regimes: 1) Fluctuation, where the filament undergoes random fluctuations because the motors are unable to bend it. 2) Rotation, in which the filament bends and then moves continuously in one direction. 3) Beating, where the filament's direction of rotation 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 to the second buckling mode of a filament undergoing a continuously distributed load. Moreover, we showed that when motors near the pining point work close to their stall force, they get stuck and act as a second pin, leading to the beating regime.