Steady-state dynamics of exclusion process with local reversible association of particles

TL;DR

This paper models the steady-state behavior of molecular motors on filaments, incorporating local reversible binding and unbinding, revealing how these processes influence phase behavior and matching simulation results.

Contribution

It introduces a novel theoretical model for molecular motor dynamics that includes local reversible association/dissociation at a defect site, expanding understanding of biological transport mechanisms.

Findings

Steady-state phases depend on association/dissociation rates.

The model predicts phase transitions influenced by local binding dynamics.

Simulation results confirm theoretical phase diagrams.

Abstract

Many biological processes are supported by special molecules, called motor proteins or molecular motors, that transport cellular cargoes along linear protein filaments and can reversibly associate to their tracks. Stimulated by these observations, we developed a theoretical model for collective dynamics of biological molecular motors that accounts for local association/dissociation events. In our approach, the particles interacting only via exclusion move along a lattice in the preferred direction, while the reversible associations are allowed at the specific site far away from the boundaries. Considering the association/dissociation site as a local defect, the inhomogeneous system is approximated as two coupled homogeneous sub-lattices. This allows us to obtain a full description of stationary dynamics in the system. It is found that the number and nature of steady-state phases strongly depend on the values of association and dissociation transition rates. Microscopic arguments to explain these observations, as well as biological implications, are also discussed. Theoretical predictions agree well with extensive Monte Carlo computer simulations.