Trina A. Schroer
Microtubule-Based Motors, Organelle Transport.
The focus of work in our lab is microtubule-based intracellular organelle transport, the process responsible for such diverse cell biological functions as membrane trafficking and mitosis. We study the microtubule motor enzyme cytoplasmic dynein and its activator, dynactin. Both are large, multiprotein complexes of several different subunits. Dynactin is believed to serve as a linker between dynein and its cargo and, as such, is required for dynein to function normally in vivo and in vitro. We are currently investigating several issues central to dynactin structure and function. By disrupting dynactin function in vivo we can explore how dynein-based motility contributes to endomembrane dynamics, mitotic spindle assembly and chromosome movement. In vitro assays for dynein/dynactin-based vesicle motility and spindle assembly allow us to identify other important molecules such as receptors and regulatory factors. These studies are being performed in different model systems such as fibroblasts, neurons, polarized epithelia and phagocytic cells, each of which emphasizes a different type of dynein-based motility. We are presently working to reconstitute dynein and dynactin from their isolated subunits to further our understanding of how the structure of each molecule contributes to its function, both in vivo and in vitro.