"The arrangement of actin filaments in 3D dictates how teams of myosin Va motors transport their cargo"
Inside a cell, material must be transported large distances to specific targets. Passive diffusion is too slow and imprecise, so eukaryotic cells employ molecular motors (like myosin Va), which use chemical energy to "walk" along the 3D network of protein filaments (like actin) of the cytoskeleton. Despite a wealth of experimental and theoretical work at the single molecule level, it is unclear how molecular motors work together to navigate their cargoes through the apparent random tangle of the cytoskeleton. I will discuss a series of experiments performed by collaborators at the University of Vermont aimed at unraveling this process, and a mathematical model that makes sense of the experimental results. The central results of this work are that: 1) measurements in 3D can differ fundamentally from similar 2D measurements; 2) the local geometry of an actin intersection dictates if and how long teams of myosin Va motors become stationary; 3) parameters like actin mesh density and cargo size can determine whether motors act as transporters or tethers. This work suggests mechanisms by which cells can regulate intracellular transport.
Dr. Walcott is an associate professor and Sinclair Professor of Mathematical Sciences. Before joining WPI, he was faculty in the math department at the University of California, Davis for eight years. With a background in biology, mechanics and applied mathematics, he did his postdoctoral fellowships at Johns Hopkins University and the University of Vermont. He received his PhD in theoretical and applied mechanics from Cornell University.