Director, MCB Program; Associate Professor of Biology, University of Massachusetts
Ph.D.: Dartmouth College
Cytoskeletal Dynamics in Living Cells
Microtubules are intracellular polymers that are required for several vital processes in eukaryotic cells including mitosis, intracellular transport and the maintenance of asymmetric cell shape. Microtubules undergo rapid rearrangements in living cells by exchange of subunits with a cellular pool. One form of exchange is treadmilling, or flux, in which equivalent rates of subunit gain and loss occur at opposite ends of the microtubule. A second type of exchange is dynamic instability in which the loss and gain of subunits occurs at the same end of the filament. To observe microtubule dynamics, we have prepared fluorescent and caged fluorescent analogs of tubulin, and are using GFP-tagged tubulin, to follow microtubule behavior in living cells. These probes are micro-injected into living cells and the dynamic behavior of the resulting fluorescent microtubules is observed and quantified using fluorescence microscopy and digital recording techniques. Using these techniques, we have directly observed the dynamic changes in microtubules as cells progress through the mitotic cycle and demonstrated that the dynamic behavior of interphase microtubules is cell type specific.
In addition, we have demonstrated that the dynamic behavior of interphase microtubules is stimulated when epithelial cells are treated with hepatocyte growth factor, which induces cell motility. Experiments are in progress to define the mechanism(s) that are used to coordinate microtubule turnover and cell motility. Molecules which interact with microtubules to generate both the distinct microtubule behavior and the specific arrangement of microtubules in diverse cells throughout development will also be determined.
U. S. Tulu, C. Fagerstrom, N. P. Ferenz, P. Wadsworth, 2006 "Molecular requirements for kinetochore-associated microtubule formation in mammalian cells" Current Biology 16:536-541.
N. M. Rusan, P. Wadsworth, 2005 "Centrosome fragments and microtubules are released and transported asymetrically away from division plane in anaphase" J. Cell Biology. 168:21-28
K. Murthy, P. Wadsworth, 2005 "Myosin-II-dependent localization and dynamics of F-actin during cytokinesis" Current Biology 15:724-731
P. Wadsworth, A. Khodjakov, 2004 "E pluribus unum: toward a universal mechanism for spindle assembly" Trends in Cell Biology 14:413-419
Tulu, U.S., N. Rusan, and P. Wadsworth. 2003. "Peripheral, non-centrosome-associated microtubules contribute to spindle formation in centrosome containing cells." Curr. Biol. 13:1894-1899.
Rusan, N., U.S. Tulu, C. Fagerstrom, and P. Wadsworth. 2002. "Microtubule rearrangment in prophase/prometaphase cells requires cytoplasmic dynein." J. Cell Biol. 158:997-1003.
Rusan, N. M., C. J. Fagerstrom, A. M. Yvon and P. Wadsworth (2001). "Cell cycle-dependent changes in microtubule dynamics in living cells expressing green fluorescent protein-alpha tubulin." Mol Biol Cell 12(4): 971-80.
Yvon, A. M., D. J. Gross and P. Wadsworth (2001). "Antagonistic forces generated by myosin II and cytoplasmic dynein regulate microtubule turnover, movement, and organization in interphase cells." Proc Natl Acad Sci U S A 98(15): 8656-61.
Yvon, A. M. and P. Wadsworth (2000). "Region-specific microtubule transport in motile cells." J Cell Biol 151(5): 1003-12.