Microtubule Defects Influence Kinesin-Based Transport In Vitro

TL;DR

This study introduces a new method to directly examine how structural defects in microtubules affect kinesin motor transport, revealing that defects can cause premature unbinding or pausing depending on motor number.

Contribution

It provides the first direct evidence linking microtubule defects to kinesin-based transport behavior in vitro.

Findings

Microtubule defects cause premature unbinding of kinesin cargos with few motors.

Defects induce pausing in cargos driven by multiple motors.

The method enables direct investigation of microtubule-motor interactions.

Abstract

Microtubules are protein polymers that form "molecular highways" for long-range transport within living cells. Molecular motors actively step along microtubules to shuttle cellular materials between the nucleus and the cell periphery; this transport is critical for the survival and health of all eukaryotic cells. Structural defects in microtubules exist, but whether these defects impact molecular motor-based transport remains unknown. Here, we report a new, to our knowledge, approach that allowed us to directly investigate the impact of such defects. Using a modified optical-trapping method, we examined the group function of a major molecular motor, conventional kinesin, when transporting cargos along individual microtubules. We found that microtubule defects influence kinesin-based transport in vitro. The effects depend on motor number: cargos driven by a few motors tended to unbind prematurely from the microtubule, whereas cargos driven by more motors tended to pause. To our knowledge, our study provides the first direct link between microtubule defects and kinesin function. The effects uncovered in our study may have physiological relevance in vivo.