Here we explore peptide inhibitors of Cdc20, a substrate-recognition subunit and activator of the E3 ubiquitin ligase the anaphase promoting complex/cyclosome (APC/C) that is essential in mitosis and ...

In in vitro assays, polyubiquitination of Mdm2 inhibited its E3 ligase activity towards p53. In contrast, SUMOylation of Mdm2 stimulated ubiquitination of p53 under these conditions.