APC/C(Cdc20) controls the ubiquitin-mediated degradation of p21 in prometaphase.
During the G1/S transition, p21 proteolysis is mediated by Skp2; however, p21 reaccumulates in G2 and is degraded again in prometaphase. How p21 degradation is controlled in mitosis remains unexplored. We found that Cdc20 (an activator of the ubiquitin ligase APC/C) binds p21 in cultured cells and identified a D box motif in p21 necessary for APC/C(Cdc20)-mediated ubiquitylation of p21. Overexpression of Cdc20 or Skp2 destabilized wild-type p21; however, only Skp2, but not Cdc20, was able to destabilize a p21(D box) mutant. Silencing of Cdc20 induced an accumulation of p21, increased the fraction of p21 bound to Cdk1, and inhibited Cdk1 activity in p21(+/+) prometaphase cells, but not in p21(-/-) cells. Thus, in prometaphase Cdc20 positively regulates Cdk1 by mediating the degradation of p21. We propose that the APC/C(Cdc20)-mediated degradation of p21 contributes to the full activation of Cdk1 necessary for mitotic events and prevents mitotic slippage during spindle checkpoint activation.
Amador
Virginia
V
Department of Pathology, NYU Cancer Institute, New York University School of Medicine, 550 First Avenue MSB 599, New York, NY 10016, USA.
Ge
Sheng
S
Santamaría
Patricia G
PG
Guardavaccaro
Daniele
D
Pagano
Michele
M
D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D016203:CDC2 Protein Kinase / Q000235:genetics / Q000378:metabolism; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000502:physiology*; D003110:Colonic Neoplasms / Q000378:metabolism / Q000473:pathology; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism*; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000235:genetics / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D005909:Glioblastoma / Q000378:metabolism / Q000473:pathology; D006801:Humans; D015151:Immunoblotting; D047468:Immunoprecipitation; D008168:Lung; D051379:Mice; D018345:Mice, Knockout; D016297:Mutagenesis, Site-Directed; D049468:Prometaphase; D044786:S-Phase Kinase-Associated Proteins / Q000235:genetics / Q000502:physiology; D025801:Ubiquitin / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000502:physiology*; D044767:Ubiquitin-Protein Ligases / Q000037:antagonists & inhibitors*
D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D050759:Cyclin-Dependent Kinase Inhibitor p21; D004791:Enzyme Inhibitors; D044786:S-Phase Kinase-Associated Proteins; D025801:Ubiquitin; D050760:Cyclin-Dependent Kinase Inhibitor p27; C577488:CDC20 protein, human; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases; D016203:CDC2 Protein Kinase