Traffic of Molecular Motors

TL;DR

This paper models the traffic behavior of molecular motors on cytoskeletal filaments using driven lattice gas models, revealing cooperative phenomena like traffic jams and phase transitions influenced by motor concentration and geometry.

Contribution

It introduces a novel modeling approach combining active movement, diffusion, and binding dynamics to analyze motor traffic and collective effects.

Findings

Motor-motor interactions cause traffic jams and phase transitions.

Jams are limited by the motor walking distance in large reservoirs.

Confined geometries lead to significantly longer traffic jams.

Abstract

Molecular motors perform active movements along cytoskeletal filaments and drive the traffic of organelles and other cargo particles in cells. In contrast to the macroscopic traffic of cars, however, the traffic of molecular motors is characterized by a finite walking distance (or run length) after which a motor unbinds from the filament along which it moves. Unbound motors perform Brownian motion in the surrounding aqueous solution until they rebind to a filament. We use variants of driven lattice gas models to describe the interplay of their active movements, the unbound diffusion, and the binding/unbinding dynamics. If the motor concentration is large, motor-motor interactions become important and lead to a variety of cooperative traffic phenomena such as traffic jams on the filaments, boundary-induced phase transitions, and spontaneous symmetry breaking in systems with two species of motors. If the filament is surrounded by a large reservoir of motors, the jam length, i.e., the extension of the traffic jams is of the order of the walking distance. Much longer jams can be found in confined geometries such as tube-like compartments.