Effect of local dissociations in bidirectional transport of driven particles

Motivated by the complex processes of cellular transport when different types of biological molecular motors can move in opposite directions along protein filaments while also detaching from them, we developed a theoretical model of the bidirectional motion of driven particles. It utilizes a totally asymmetric simple exclusion process framework to analyze the dynamics of particles moving in opposite directions along the lattice of discrete sites while the particles might also dissociate from the filament in the bulk of the system. Mean-field theoretical arguments supported by extensive Monte Carlo simulations are presented in order to understand how the localized particle dissociations affect the bidirectional dynamics and spontaneous symmetry-breaking phenomena. It is found that changes in the amplitudes and in the symmetry of dissociation rates lead to significant modifications in the dynamic properties and in the stationary phase diagrams. These changes are explained using simple physical arguments. Our theoretical method clarifies some aspects of microscopic mechanisms of complex transport phenomena in biological systems. (paper)