Kinesins transport a variety of cargo along microtubules (MTs) in the cytoplasm. Although much is known about the walking of a kinesin along a single MT, the effects of the spatial distribution of MTs on kinesin-mediated transport cannot be sufficiently understood and quantified using existing models. In this study, we present a stochastic model to study the dynamics of a kinesin in the presence of two MTs. Our model can predict the Brownian motion of the cargo, mechanochemical cycle of kinesin walking, and the unbinding and rebinding of kinesin on neighboring MTs. Specifically, a stress-influenced chemical kinetics was considered to describe changes in the walking and unbinding of a kinesin along one MT due to the neighboring MT. In addition, the effects of the neighboring MT on the rebinding of a kinesin to MTs were calibrated using a spatial marching method. By integrating these dynamics, our model predicted a significant disturbance in the transport of kinesin when the distance between two intersected MTs is close to the radius of the cargo and the two MTs have antiparallel orientations. Moreover, shorter kinesins (i.e., kinesins with a short cargo linker) are more likely to stop the transport near the intersection than longer kinesins.

• Received 20 June 2018

DOI:https://doi.org/10.1103/PhysRevE.98.052412