Role of interactions and correlations on collective dynamics of molecular motors along parallel filaments

TL;DR

This paper introduces a new theoretical model and approach to analyze how interactions and correlations influence the collective dynamics of molecular motors along parallel filaments, aligning with experimental data.

Contribution

A novel thermodynamically consistent two-channel exclusion process model with a modified vertical cluster mean field approach for analyzing motor interactions.

Findings

Optimal interaction strength for maximal current occurs at weak repulsive interactions.

Increasing coupling rate decreases the optimal interaction strength, approaching experimental values.

Correlations are short-range for weak interactions and long-range for strong attractions.

Abstract

Cytoskeletal motors known as motor proteins are molecules that drive cellular transport along several parallel cytoskeletal filaments and support many biological processes. Experimental evidences suggest that they interact with the nearest molecules of their filament while performing mechanical work. To understand such mechanism theoretically, a new version of two-channel totally asymmetric simple exclusion process which incorporates interactions in a thermodynamically consistent way, is introduced. As the existing approaches for multi-channel systems deviate from analyzing the effect of inter and intra channel interactions, a new approach known as modified vertical cluster mean field is developed. The approach along with monte-carlo simulations successfully encounters some correlations and computes all complex dynamic properties of the system. Role of symmetry of interactions and inter-channel coupling is observed on triple points and particle maximal current. Surprisingly, for each coupling rate and most of the interaction splittings, there corresponds an optimal interaction strength for the maximal current which belongs to the case of weak repulsive interactions. Moreover, for a fixed interaction splitting, as coupling rate increases, the optimal strength decreases and tends towards the experimental predictions. Correlations are found to be short-range and weaker for repulsive and weak attractive interactions, while for stronger attractions they are long-range and stronger. All these findings are also discussed in the context of experimental observations.