Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences


Hudson, John




The Polo like kinase (Plk) family members are critical regulators of cell cycle progression, mitosis, cytokinesis and the DNA damage response. While much is known regarding the phenotype associated with loss or overexpression of Sak, less than a handful of interacting partners/substrates are known. Therefore, the identification and characterization of Sak interacting partners will contribute to our understanding of the essential role of Sak in the cell.

Our results show that Sak physically interacts with and co-localizes with Cyclin B1. Furthermore, we identified, Gadd45a as both an interacting partner and a substrate for Sak. The site of phosphorylation was putatively identified as Tyr151 on Gadd45a. In addition, we found that endogenous Sak protein levels are decreased in response to UV and that this decrease is p53-dependent. These findings suggest that Sak in addition to Sak playing a role in centrosome duplication that it may also function in mitotic entry and DNA damage response pathways.