On the kinetics that moves Myosin V

TL;DR

This paper presents a Markov model highlighting the kinetic asymmetry in molecular motors like Myosin V, revealing how dynamical activity determines motor direction through a fluctuation symmetry.

Contribution

It introduces a simple Markov model emphasizing the kinetic, non-thermodynamic aspects of molecular motor transport, focusing on dynamical activity asymmetry.

Findings

Identification of a fluctuation symmetry in dynamical activity.

Direction of motor motion determined by antisymmetric dynamical activity.

Kinetic asymmetry, not thermodynamics, drives motor function.

Abstract

Molecular motor proteins such as Myosin V, Dynein or Kinesin are no ratchets, at least not with a flashing asymmetric potential; the crucial asymmetry is in the dynamical activity. We make that explicit in terms of a simple Markov model, emphasizing the kinetic (and non-thermodynamic) aspects of stochastic transport. The analysis shows the presence of a fluctuation symmetry in that part of the dynamical activity which is antisymmetric under reversal of trailing and leading head of the motor. The direction of the motor motion is determined by it.