Model for the unidirectional motion of a dynein molecule

TL;DR

This paper presents a simple model for dynein's unidirectional movement along microtubules, accounting for variable step sizes influenced by force and ATP concentration, and analyzes how velocity and dispersion change with load.

Contribution

It introduces a novel, adaptable model that incorporates step size variations based on experimental factors, advancing understanding of dynein's motility mechanisms.

Findings

Velocity varies with applied load and ATP levels.

Dispersion in displacement depends on force and biochemical conditions.

Model can be extended to include structural and processivity details.

Abstract

Cytoplasmic dyneins transport cellular organelles by moving on a microtubule filament. It has been found recently that depending on the applied force and the concentration of the adenosine triphosphate (ATP) molecules, dynein's step size varies. Based on these studies, we propose a simple model for dynein's unidirectional motion taking into account the variations in its step size. We study how the average velocity and the relative dispersion in the displacement vary with the applied load. The model is amenable to further extensions by inclusion of details associated with the structure and the processivity of the molecule.