DNA replication in higher eukaryotes requires activation of a Cdk2 kinase by Cdc25A, a labile phosphatase subject to further destabilization upon genotoxic stress. We describe a distinct, markedly stable form of Cdc25A, which plays a previously unrecognized role in mitosis. Mitotic stabilization of Cdc25A reflects its phosphorylation on Ser17 and Ser115 by cyclin B-Cdk1, modifications required to uncouple Cdc25A from its ubiquitin-proteasome-mediated turnover. Cdc25A binds and activates cyclin B-Cdk1, accelerates cell division when overexpressed, and its downregulation by RNA interference (RNAi) delays mitotic entry. DNA damage-induced G(2) arrest, in contrast, is accompanied by proteasome-dependent destruction of Cdc25A, and ectopic Cdc25A abrogates the G(2) checkpoint. Thus, phosphorylation-mediated switches among three differentially stable forms ensure distinct thresholds, and thereby distinct roles for Cdc25A in multiple cell cycle transitions and checkpoints.
- MeSH
- cyklin B metabolismus MeSH
- fosfatasy cdc25 chemie metabolismus MeSH
- fosforylace MeSH
- G2 fáze * MeSH
- lidé MeSH
- mitóza * MeSH
- molekulární sekvence - údaje MeSH
- poškození DNA MeSH
- proteinkinasa CDC2 metabolismus MeSH
- sekvence aminokyselin MeSH
- serin metabolismus MeSH
- stabilita enzymů MeSH
- ubikvitin metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- MeSH
- experimenty na zvířatech MeSH
- fraktury kostí patologie terapie MeSH
- hojení ran MeSH
- imobilizace MeSH
- krysa rodu rattus MeSH
- regenerace kostí MeSH
- Check Tag
- krysa rodu rattus MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- fixace fraktur MeSH
- krysa rodu rattus MeSH
- nemoci kostí terapie MeSH
- senioři MeSH
- Check Tag
- krysa rodu rattus MeSH
- senioři MeSH
- MeSH
- elektronová mikroskopie MeSH
- experimenty na zvířatech MeSH
- fraktury femuru patofyziologie patologie ultrastruktura MeSH
- fraktury kostí patofyziologie patologie ultrastruktura MeSH
- fraktury tibie patofyziologie patologie ultrastruktura MeSH
- hojení ran MeSH
- krysa rodu rattus MeSH
- regenerace kostí MeSH
- Check Tag
- krysa rodu rattus MeSH
- Publikační typ
- srovnávací studie MeSH