BRCA1-dependent Chk1 phosphorylation triggers partial chromatin disassociation of phosphorylated Chk1 and facilitates S-phase cell cycle arrest
| Autor: | Moshe Z. Papa, Shabana Shabbeer, Sally Metsuyanim, Ronit I. Yarden, Itay Pickholtz, Hadass Tellio |
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| Rok vydání: | 2012 |
| Předmět: |
DNA Replication
animal structures Cell cycle checkpoint Biology environment and public health Biochemistry Article S Phase Phosphorylation cascade Phosphoserine Stress Physiological Cell Line Tumor Radiation Ionizing Humans Hydroxyurea CHEK1 Phosphorylation skin and connective tissue diseases BRCA1 Protein Kinase Cell Cycle Checkpoints Cell Biology G2-M DNA damage checkpoint Chromatin Enzyme Activation enzymes and coenzymes (carbohydrates) Checkpoint Kinase 1 Cancer research Origin recognition complex Mutant Proteins biological phenomena cell phenomena and immunity Protein Kinases DNA Damage Signal Transduction |
| Zdroj: | The International Journal of Biochemistry & Cell Biology. 44:1761-1769 |
| ISSN: | 1357-2725 |
| DOI: | 10.1016/j.biocel.2012.06.026 |
| Popis: | Chk1 phosphorylation by the PI3-like kinases ATR and ATM is critical for its activation and its role in prevention of premature mitotic entry in response to DNA damage or stalled replication. The breast and ovarian tumor suppressor, BRCA1, is among several checkpoint mediators that are required for Chk1 activation by ATM and ATR. Previously we showed that BRCA1 is necessary for Chk1 phosphorylation and activation following ionizing radiation. BRCA1 has been implicated in S-phase checkpoint control yet its mechanism of action is not well characterized. Here we report that BRCA1 is critical for Chk1 phosphorylation in response to inhibition of replication by either cisplatin or hydroxyurea. While Chk1 phosphorylation of S317 is fully dependent on BRCA1, additional proteins may mediate S345 phosphorylation at later time points. In addition, we show that a subset of phosphorylated Chk1 is released from the chromatin in a BRCA1-dependent manner which may lead to the phosphorylation of Chk1 substrate, Cdc25C, on S216 and to S-phase checkpoint activation. Inhibition of Chk1 kinase by UCN-01 or expression of Chk1 phosphorylation mutants in which the serine residues were substituted with alanine residues abrogates BRCA1-dependent cell cycle arrest in response replication inhibition. These data reveal that BRCA1 facilitates Chk1 phosphorylation and its partial chromatin dissociation following replication inhibition that is likely to be required for S-phase checkpoint signaling. |
| Databáze: | OpenAIRE |
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