cell division control protein 5, interaction, binding location


Cell division control protein 5 (Cdc5) is a mitotic kinase responsible for several events during meiosis and mitosis, including mitotic exit. Dbf4-Cdc5 binding has been shown to inhibit Cdc5 activity. Dbf4 binds in the Polo box domain (PBD) of Cdc5. Mutations in the WHK residues causes a loss of interaction between the PBD and its phospho-substrates. However, interaction is maintained with Dbf4, suggesting that Dbf4 bind to the PBD at a unique binding location. My goal was to determine this binding location. The yeast two-hybrid system was used to screen randomly PCR-generated PBD mutations for interaction with Dbf4-R83E (a mutation shown to lose interaction with Cdc5). Six plasmids were isolated and further analyzed with another yeast two-hybrid cross. None of these plasmids proved to carry the mutation that rescued the interaction between Dbf4-R83E and the PBD of Cdc5.