• Cell biology of mitotic spindle assembly and function

In animals, the microtubule cytoskeleton is reorganized as cells enter mitosis. Microtubules transition from a largely radial array into a football-shaped structure called the mitotic spindle. The job of the spindle is to transfer a complete set of chromosomes into each of two daughter cells that are born from a cell division. Mistakes during this process are costly, as errors in chromosome segregation can initiate cancer or cause cell death.

How does the spindle form, and how does it mediate chromosome segregation? The Ohi lab studies these questions using live cell imaging and reconstitution biochemistry. We are interested in how bipolarity of the spindle is established, and the mechanisms that govern its shape and size. We study how chromosomes move within the spindle, with a focus on protein factors that govern microtubule dynamics at the kinetochore-microtubule interface.

  • The Tubulin Code

Metazoans express many isoforms of α- and β-tubulin, and it is becoming increasingly clear that many tubulin isoforms perform context-dependent functions. The functional versatility of tubulin is further extended by post-translational modifications. Although a handful of tubulin post-translational modifications are well-established, it is likely that many remain unknown. The “writers” and “readers” of tubulin post-translational modifications also remain largely unexplored. Using proteomic and cell biology approaches, we are working to uncover new tubulin post-translational modifications that are expressed in specific physiological states. We are also developing pipelines to identify readers of specific tubulin post-translational modifications, with the goal of understanding how cells interpret the tubulin code, and leverage its complexity to carry out essential cellular processes.