Intracullular Cargo Transport
Myosin Va is a double-headed molecular motor that transports intracellular cargo by taking numerous ~36 nm steps along its actin track (see animation). Although a single motor can carry cargo, normally teams of myosin Va motors share this responsibility. Complicating matters is that the intracellular highway these motors travel on is a 3-dimensional meshwork that presents both a physical barrier and a directional challenge to the delivery of cargo to its destination. To address this dilemma we use both simplified in vitro model systems of myosin Va transport within biomimetic actin cytoskeletons and in vivo transport in tissue cultured cells (see movie of insulin granule transport in INS-1 cells). Using the laser trap, single molecule fluorescence detection techniques, and super-resolution microscopy (STORM), we are in a position to define the molecular mechanisms underlying myosin Va’s capacity as a single motor or within teams to maneuver cargo through Mother Nature’s 3-dimensional actin filament maze. These studies require expertise in molecular biophysics, protein expression (in collaboration with Dr. Kathleen Trybus). and biological systems modeling (in collaboration with Dr. Sam Walcott).
This movie shows the transport of 350nm liposomes by ~10 myosin Va motors on each liposome through a 3-D actin network suspended off of 3µm beads. Video recording accomplished using STORM super-resolution microscopy. The color bar represents the height of the actin in the Z-dimension.