Katharine S. Ullman

My lab is interested in the processes that guide reformation of nuclear architecture following mitosis and how this is integrated with genome surveillance and cell division regulation. Our long-term goals are to use this information to better understand how deregulation of these events contributes to tumor formation and progression and, ultimately, to identify targets that can be used to find new inhibitors of cancerous cell growth.

At interphase, the nucleus and cytoplasm of a eukaryotic cell provide unique environments for specialized processes. The nuclear envelope, formed by two membrane bilayers, provides a barrier between these two main compartments, while at the same time, nuclear pore complexes provide channels through which regulated traffic can take place across this barrier. We are interested in learning how individual components of the pore function both in transport and also in non-canonical roles, such as the response to DNA damage.

When a higher eukaryotic cell divides, the nucleus undergoes dramatic morphological remodeling and nuclear and cytoplasmic contents intermix. The nuclear pore complex also disperses at this time. As soon as chromosomes begin to separate in mitosis, the nuclear envelope begins to reform. We are studying how pore proteins, as well as other factors, participate in processes critically important to coordinating nuclear envelope formation and establishing normal nuclear architecture.

We are also capitalizing on the discovery that loss of post-mitotic function of the pore protein Nup153 results in activation of the abscission checkpoint, halting progression through cytokinesis, the last step of cell division. Working collaboratively with the Sundquist lab, we are studying how the role for ESCRT factors in cytokinetic abscission is regulated by this checkpoint.