Multi-Motor Cargo Navigation in Complex Cytoskeletal Networks

TL;DR

This study investigates how the number of kinesin motors and microtubule network density influence cargo transport dynamics in vitro, revealing key physical factors that regulate intracellular cargo navigation.

Contribution

It provides new insights into how motor number and network density physically control kinesin-driven cargo transport in complex microtubule networks.

Findings

Multiple motors increase cargo speed and path tortuosity.

Network mesh size affects cargo end-to-end distance and run time.

Motor number and network density jointly regulate cargo navigation.

Abstract

The kinesin superfamily of motor proteins is a major driver of anterograde transport of vesicles and organelles within eukaryotic cells via microtubules. Numerous studies have elucidated the step-size, velocities, forces, and navigation ability of kinesins both in reconstituted systems and in live cells. Outside of cells, the kinesin-based transport is physically regulated and can be controlled by obstacles or defects in the path, or the interaction between several motors on the same cargo. To explore the physical control parameters on kinesin-driven transport, we created complex microtubule networks in vitro to test how kinesin cargoes made from quantum dots with one to 10 kinesin motors attached are able to navigate the network. We find that many motors on the quantum dot significantly alter distance walked, time spent bound, the average speed, and the tortuosity of the cargo. We also find that the average mesh size of the microtubule network affects the end-to-end distance of the motion, the run time, average speed and tortuosity of cargoes. Thus, both motor number and network density are physical aspects that regulate where cargoes traverse in space and time.