Unraveling on Kinesin Acceleration in Intracellular Environments: A Theory for Active Bath

TL;DR

This paper develops a theoretical model using an active bath of Ornstein-Uhlenbeck particles to explain how kinesin motors and attached probes are accelerated in the complex intracellular environment, supported by simulations and analytical solutions.

Contribution

It introduces a novel active bath model with a derived generalized Langevin equation to explain kinesin acceleration in living cells, combining simulations and theoretical analysis.

Findings

Active bath accelerates kinesin and probes.

Derived GLE matches simulation results.

Noise variance dominates probe acceleration.

Abstract

Single molecular motor kinesin harnesses thermal and non-thermal fluctuations to transport various cargoes along microtubules, converting chemical energy to directed movements. To describe the non-thermal fluctuations generated by the complex environment in living cells, we establish a bottom-up model to mimic the intracellular environment, by introducing an active bath consisting of active Ornstein-Uhlenbeck (OU) particles. Simulations of the model system show that kinesin and the probe attached to it are accelerated by such active bath. Further, we provide a theoretical insight into the simulation result by deriving a generalized Langevin equation (GLE) for the probe with a mean-field method, wherein an effective friction kernel and fluctuating noise terms are obtained explicitly. Numerical solutions of the GLE show very good agreement with simulation results. We sample such noises, calculate their variances and non-Gaussian parameters, and reveal that the dominant contribution to probe acceleration is attributed to noise variance.