Professor Sam Walcott, Director of Bioinformatics and Computational Biology and the Sinclair Professor in Mathematical Sciences, has published a new paper titled "Kinesin-1- transported liposomes prefer to go straight in 3D microtubule intersections by a mechanism shared by other molecular motors" in the Proceedings of the National Academy of Sciences of the United States of America. Part of his research focuses on molecular motors, which are able to move material around the inside of cells. This is done by utilizing chemical energy to "walk" along the cytoskeleton, the network of protein filaments that forms the interior scaffold of the cell. While much is known about how single motors work, less is known about how multiple motors work together to transport a shared cargo.
In the project, a collaboration with David Warshaw and members of his lab (Brandon Bensel, Samantha Beck Previs) and Kathleen Trybus and members of her lab (Carol Bookwalter) at the University of Vermont, suspended "intersections" of protein filaments were constructed and fluid-like cargoes were viewed as ~10 kinesin-1 molecular motors worked together to transport their cargo through the intersection. Surprisingly, motors mostly transported the cargo straight through the intersections rather than turn, even when the intersection acted as a physical barrier. An unrelated molecular motor (myosin) was also previously observed on different protein filaments to have a preference for straight paths. Using computer simulations, this newly published work brings insight into a conserved fundamental mechanism for navigating cargoes through cytoskeletal intersections en route to their intracellular destination.
A model intracellular cargo made from phospholipids (magenta) is transported, as in cells, through a 3D intersection of microtubules (blue) by a kinesin molecular motor (yellow) team. Kinesin motors can transport the cargo straight past the crossing microtubule obstacle, by engaging in a tug-of-war to pull the cargo around the crossing microtubule on its way to its destination. Image Credit: Sam Walcott, Brandon M. Bensel, and David M. Warshaw.