Professor of Oncological Sciences and Adjunct Professor of Biochemistry
B.A. Northwestern University
Ph.D. Stanford University
Katie Ullman's Lab Page
Katie Ullman's PubMed Literature Search
Molecular Biology Program
Cell Division, Nuclear Transport, DNA damage, Protein methylation, Biomarkers
My lab is interested in the nuclear pore complex, the mitotic roles of nuclear pore proteins, and – more generally – the process of how cellular architecture is remodeled at mitosis. Our long-terms goals are to use this information to better understand how deregulation of these events contributes to both 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, forms 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 contribute to selective trafficking.
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. Interestingly, certain components of the nuclear pore adopt new roles at mitosis. We discovered that this is the case for the nuclear pore protein Nup153 and we are now pursuing this in more depth in order to gain new insight into events that contribute to nuclear remodeling and mitosis in general.
We take advantage of two complementary experimental systems to dissect the mitotic functions of Nup153 and other proteins of interest. The first is a cell-free system in which material from Xenopus (frog) eggs can be used to not only reconstitute nuclei in vitro, but also to study events triggered by mitotic conditions, such as nuclear envelope breakdown. This system can be readily manipulated to alter the function of particular proteins and study the effect that this has on a specific process. The second approach is RNAi in mammalian cells, followed by both fixed cell analysis and live imaging techniques.
These approaches have revealed that Nup153 contributes to cell division in novel, unexpected ways. Most recently, we discovered that the role for Nup153 in post-mitotic nuclear pore assembly ties into an Aurora B-mediated abscission checkpoint.
A second area of research emerging in the lab is centered on understanding the regulation of the tumor suppressor PDCD4, which we have found can switch to being a factor that promotes tumor growth under specific circumstances. This project, conducted in collaboration with Alana Welm's lab, combines many approaches, from protein partnership analysis to orthotopic xenografts to study tumor growth properties. PDCD4 is known to regulate protein translation, a role we are now focusing on in terms of understanding this new functional context of PDCD4.
Panel A. These are oocytes injected with red fluorescent dextran into the nucleus
and green fluorescent dextran into the cytoplasm. The oocyte on the left has an intact
nuclear envelope, whereas nuclear envelope breakdown has initiated in the oocyte at
right. [Suzanne Elgort]
Panel B. These are nuclei assembled in a cell-free system and incubated with a red fluorescent protein that is imported through the newly formed nuclear pores (membranes are stained green, DNA is stained blue). [Jin Liu]
Panel C. This is the nucleus of a cultured human cell, where nuclear pores (red) and COPI membrane remodeling machinery (green) are being monitored as the cell progresses into mitosis. [Amy Prunuske; note: the panels are not shown at the same scale]
- Sundquist, W.I., and Ullman, K.S. (2015) CELL BIOLOGY. An ESCRT to seal the envelope, Science, 348:1314-5
- Mackay, D.R., and Ullman, K.S. (2015) ATR and a Chk1-Aurora B pathway coordinate postmitotic
genome surveillance with cytokinetic abscission, Molecular Biology of the Cell, 26:2217-26
- Fay, M.M., Clegg, J.M., Uchida, K.A., Powers, M.A., and Ullman, K.S. (2014) Enhanced Arginine Methylation of Programmed Cell Death 4 during Nutrient Deprivation Promotes Tumor Cell Viability, Journal of Biological Chemistry, 289:17541-52
- Chow, K.-H., Elgort, S.W., Dasso, M., Powers, M.A., and Ullman, K.S. (2014) The SUMO proteases SENP1 and SENP2 play a critical role in nucleoporin homeostasis and nuclear pore complex function, Molecular Biology of the Cell, 25:160-8
- Makise, M., Mackay, D.R., Elgort, S., Shankaran, S.S., Adam, S.A., and Ullman, K.S. (2012) The Nup153-Nup50 interface and its role in nuclear import, Journal of Biological Chemistry, 287:38515-22
- Chow, K.-H., Factor, R.E., and Ullman, K.S. (2012) The Nuclear Envelope Environment and Its Cancer Connections, Nature Reviews Cancer, 12:196-209
- Powers, M.A.#, Fay, M.M.#, Factor, R.E., Welm, A.L*., and Ullman, K.S.* (2011) PRMT5 accelerates tumor growth by arginine methylation of the tumor suppressor PDCD4, Cancer Research, 71:5579-87 (#*equal contribution)
- Mackay, D., Makise, M., and Ullman, K.S. (2010) Defects in nuclear pore assembly lead to activation of an Aurora B-mediated abscission checkpoint, Journal of Cell Biology, 191:923-31
- Mackay, D., Elgort, S., and Ullman, K.S. (2009) The nucleoporin Nup153 has separable roles in both early mitotic progression and the resolution of mitosis, Molecular Biology of the Cell, 20:1652-60
- Higa, M., Alam, S., Sundquist, W., and Ullman, K.S. (2007) Molecular characterization of the Ran-binding zinc finger domain, Journal of Biological Chemistry, 282:17090-100
- Ball, J.R., Dimaano, C., Bilak, A., Zundel, M.T., and Ullman, K.S. (2007) Sequence preference in RNA recognition by the nucleoporin Nup153, Journal of Biological Chemistry, 282:8734-40
- Prunuske, A., Liu, J., Elgort, S., Joseph, J., Dasso, M., and Ullman, K.S. (2006) Nuclear envelope breakdown is coordinated by both Nup358/RanBP2 and Nup153, two nucleoporins with zinc finger modules, Molecular Biology of the Cell, 17:760-760
- Prunuske, A., and Ullman, K.S. (2006) The Nuclear Envelope: form and reformation, Current Opinion in Cell Biology, 18:108-16
- Liu, J., Prunuske, A.J., Fager, A.M., and Ullman, K.S. (2003) The COPI complex functions in nuclear envelope breakdown and is recruited by the nucleoporin Nup153, Developmental Cell, 5:487-498