Fcp1-dependent dephosphorylation is required for M-phase-promoting factor inactivation at mitosis exit.
Correct execution of mitosis in eukaryotes relies on timely activation and inactivation of cyclin B-dependent kinase 1 (cdk1), the M-phase-promoting factor (MPF). Once activated, MPF is sustained until mitotic spindle assembly by phosphorylation-dependent feedback loops that prevent inhibitory phosphorylation of cdk1 and ubiquitin-dependent degradation of cyclin B. Whether subsequent MPF inactivation and anaphase onset require a specific phosphatase(s) to reverse these feedback loops is not known. Here we show through biochemical and genetic evidence that timely MPF inactivation requires activity of the essential RNA polymerase II-carboxy-terminal domain phosphatase Fcp1, in a transcription-independent manner. We identify Cdc20, a coactivator of the ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C) required for cyclin degradation and anaphase onset, USP44, a deubiquitinating peptidase that opposes APC/C action, and Wee1, a cdk1 inhibitory kinase, as relevant Fcp1 targets. We propose that Fcp1 has a crucial role in the liaison between dephosphorylation and ubiquitination that drives mitosis exit.
CEINGE Biotecnologie Avanzate, via Gaetano Salvatore 486, 80145 Naples, Italy.
Roberta
R
Visconti
Luca
L
Palazzo
Rosa
R
Della Monica
Domenico
D
Grieco
D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D010450:Endopeptidases / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D016200:Maturation-Promoting Factor / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000235:genetics / Q000502:physiology*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000235:genetics / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D064570:Ubiquitin-Specific Proteases
D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; C577488:CDC20 protein, human; D011505:Protein-Tyrosine Kinases; C499349:WEE1 protein, human; D016200:Maturation-Promoting Factor; D010749:Phosphoprotein Phosphatases; C116022:carboxy-terminal domain phosphatase; D010450:Endopeptidases; D064570:Ubiquitin-Specific Proteases