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

Abstract

Cytoskeletal motors known as motor proteins are molecules that drive cellular transport along several parallel cytoskeletal filaments and support many biological processes. Experimental evidence suggests that they interact with the nearest molecules of their filament while performing any 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 combined 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 the complex dynamic properties of the system. Role of symmetry of interactions and inter-channel coupling is observed on the triple points and the particle maximal current. Surprisingly, for all values of coupling rate and most of the interaction splittings, the optimal interaction strength corresponding to maximal current belongs to the case of weak repulsive interactions. Moreover, for weak interaction splittings and with an increase in the coupling rate, the optimal interaction strength tends towards the known experimental results. Coupling in between the lanes decreases the correlations. They are found to be short-range and weaker for repulsive and weak attractive interactions, while long-range and stronger for large attractions.