Morphological and dynamical properties of semiflexible filaments driven by molecular motors

TL;DR

This paper models the complex behavior of semiflexible filaments driven by molecular motors, revealing how motor activity influences filament morphology, fluctuations, and transition to spiral shapes in a non-equilibrium setting.

Contribution

It introduces an explicit stochastic model of motor-filament interactions, capturing load-dependent detachment, non-linear motor velocity, and resulting non-equilibrium filament dynamics.

Findings

Filament exhibits modified bending stiffness and spiral morphology.

Motor activity causes correlated fluctuations and ballistic-diffusive dynamics.

End-to-end distribution reflects non-equilibrium behavior.

Abstract

We consider an explicit model of a semiflexible filament moving in two dimensions on a gliding assay of motor proteins, which attach to and detach from filament segments stochastically, with a detachment rate that depends on the local load experienced. Attached motor proteins move along the filament to one of its ends with a velocity that varies non-linearly with the motor protein extension. The resultant force on the filament drives it out of equilibrium. The distance from equilibrium is reflected in the end-to-end distribution, modified bending stiffness, and a transition to spiral morphology of the polymer. The local stress dependence of activity results in correlated fluctuations in the speed and direction of the center of mass leading to a series of ballistic-diffusive crossovers in its dynamics.