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

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.