Kinesin-Cargo Motility in Random Microtubule Networks

Abstract

Microtubules perform a major role in intracellular transportation, a complex and highly regulated process of motor driven transport of cargos such as organelles, protein complexes, and vesicles. Transport is essential for the survival, development, and maintenance of cells. Kinesin-1 is a major motor protein responsible for plus-end directed transport along microtubules in many cell types. Prior work in our laboratory involved studying the effect of crowding on single motors and artificial quantum-dot “cargos.” We found that single molecules were hindered in crowded conditions, but cargos were still able to move long distances. Further, we found that the orientation of multiple microtubules within bundles can alter where and how fast single motors move. Using this technique of imaging quantum-dot cargoes in a single molecule assay, we are interested to learn how single motors and cargos transport in random networks of microtubules that are bundled or crossed. We find that cargos continue to transport, but can become locally pinned to a particular location because of the local orientation and directionality of the microtubules. We are analyzing the mean squared displacements over time to determine the type of motility they display compared to multiple models of particle transport.