Peptide inhibitors of Cell Division Cycle 20-dependent Anaphase-Promoting Complex (APCCdc20) activity

• Main Authors: Yi Shan Ding, 丁乙珊
• Other Authors: S. C. Schuyler
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/u92228

碩士 === 長庚大學 === 生物醫學研究所 === 104 === The spindle checkpoint prevents cell cycle progression in response to unattached kinetochores by regulating the activity of Anaphase Promoting Complex or Cyclosome (APC), an E3-ubiquitin ligase. Cell Division Cycle 20 (Cdc20) plays a bi-functional role and can either serve as a co-activator of the APC or be targeted for mitotic arrest by interacting with one of the mitotic checkpoint components, Mitotic Arrest Deficient 2 (Mad2) via Mad2-binding motif (MB-motif). By employing an in vitro quantitative APCCdc20 enzyme assay, we have observed that excess amounts of MB-motif-based peptides were sufficient to disrupt APCCdc20 activity. Mutation analyses revealed residues important for inhibition of APCCdc20 activity. In addition to the highly-conserved KILR motif, other conserved amino acids residues were observed to play an essential role in inhibiting APCCdc20 activity. I have also observed the inhibitory effects of MB-motif derived peptides on APCCdh1 enzyme activity, indicating the peptides inhibitors might primarily targeted APC rather than Cdc20. Physical interactions between wild-type and mutant forms of peptides and the APC were demonstrated by pull-down assays. We hypothesize that Cdc20 MB-motif derived peptides may compete with MB-motif or the C-box binding sites on the APC.