Title: Movement of Kinesin Cargos on Microtubules with Varying Numbers of Motor Proteins

Kinesin motor proteins facilitate anterograde transport of vesicles and organelles in many eukaryotic cells by “walking” along microtubule networks that can range from simple linear paths in the neuronal axon to complex, chaotic networks in lung and kidney cells. Our project aims to elucidate what factors impact a kinesin protein’s path through a network of microtubules by examining the trajectories and association times of cargo molecules attached to kinesin proteins. We constructed microtubule networks of varying mesh sizes and tracked the paths taken by cargo molecules constructed by attaching and average of 1, 5 or 10 kinesin proteins to a quantum dot. We found that increasing the number of motors led to clear changes in how far the cargo traveled, how long it stayed attached to the microtubule, its average velocity, and the tortuosity of its path. This along with previous work has led us to conclude that mesh density and motor count are key factors in determining how a cargo will navigate a microtubule network.