The cell’s ability to sense and respond to mechanical forces is crucial to many biological processes, including cell division and differentiation. Our laboratory uses novel biophysical methods which combine controlled micromanipulation techniques (e.g., laser tweezers, glass microfibers) and high-resolution fluorescence microscopy (e.g., confocal and TIRF imaging) to characterize physicochemical nature of the mitotic spindle and the cell nucleus. Thorough quantitative analyses of their micromechanics and molecular biochemistry, we aim to understand the principles of how cells are structured to respond to defined mechanical cues and ultimately to control cellular behavior.
(A) Xenopus laevis, our primary model organism. Eggs from female frogs (B) are used to prepare cytoplasmic extracts, in which the spindle apparatus and the cell nucleus can be in vitro assembled and micromanipulated. Image in (C) shows a metaphase spindle assembled in extracts and visualized by fluorescently labeled tubulin. A pair of glass microfibers can be used to apply mechanical force. Inset illustrates the geometry of the set-up
Shimamoto, Y., Forth, S., and Kapoor, T.M. (2015). Measuring pushing and braking forces generated by ensembles of kinesin-5 crosslinking two microtubules. Dev Cell 34, 669-681.
Takagi, J., Itabashi, T., Suzuki, K., Kapoor, T.M., Shimamoto, Y., and Ishiwata, S. (2013). Using micromanipulation to analyze control of vertebrate meiotic spindle size. Cell Rep 5, 44-50.
Shimamoto, Y., Maeda, Y.T., Ishiwata, S., Libchaber, A.J., and Kapoor, T.M. (2011). Insights into the micromechanical properties of the metaphase spindle. Cell 145, 1062-1074.