Letter | Published:

BRCA1 regulates the G2/M checkpoint by activating Chk1 kinase upon DNA damage

Nature Genetics volume 30, pages 285289 (2002) | Download Citation

Subjects

Abstract

The breast cancer tumor-suppressor gene, BRCA1, encodes a protein with a BRCT domain—a motif that is found in many proteins that are implicated in DNA damage response and in genome stability1. Phosphorylation of BRCA1 by the DNA damage-response proteins ATM, ATR and hCds1/Chk2 changes in response to DNA damage and at replication-block checkpoints2,3,4,5. Although cells that lack BRCA1 have an abnormal response to DNA damage, the exact role of BRCA1 in this process has remained unclear. Here we show that BRCA1 is essential for activating the Chk1 kinase that regulates DNA damage–induced G2/M arrest. Thus, BRCA1 controls the expression, phosphorylation and cellular localization of Cdc25C and Cdc2/cyclin B kinase—proteins that are crucial for the G2/M transition. We show that BRCA1 regulates the expression of both Wee1 kinase, an inhibitor of Cdc2/cyclin B kinase, and the 14-3-3 family of proteins that sequesters phosphorylated Cdc25C and Cdc2/cyclin B kinase in the cytoplasm6. We conclude that BRCA1 regulates key effectors that control the G2/M checkpoint and is therefore involved in regulating the onset of mitosis.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    et al. A superfamily of conserved domains in DNA damage-responsive cell cycle checkpoint proteins. FASEB J. 11, 68–76 (1997).

  2. 2.

    , , & Requirement of ATM-dependent phosphorylation of brca1 in the DNA damage response to double-strand breaks. Science 286, 1162–1166 (1999).

  3. 3.

    et al. Functional interactions between BRCA1 and the checkpoint kinase ATR during genotoxic stress. Genes Dev. 14, 2989–3002 (2000).

  4. 4.

    , , , & hCds1-mediated phosphorylation of BRCA1 regulates the DNA damage response. Nature 404, 201–204 (2000).

  5. 5.

    Ataxia telangiectasia-related protein is involved in the phosphorylation of BRCA1 following deoxyribonucleic acid damage. Cancer Res. 60, 5037–5039 (2000).

  6. 6.

    , , & Nuclear localization of Cdc25 is regulated by DNA damage and a 14-3-3 protein. Nature 397, 172–175 (1999).

  7. 7.

    et al. Characterization of a breast cancer cell line derived from a germ-line BRCA1 mutation carrier. Cancer Res. 58, 3237–3242 (1998).

  8. 8.

    et al. Genetic analysis of BRCA1 function in a defined tumor cell line. Mol. Cell 4, 1093–1099 (1999).

  9. 9.

    et al. Γ-rays-induced death of human cells carrying mutations of BRCA1 or BRCA2. Oncogene 18, 7334–7342 (1999).

  10. 10.

    , & Involvement of BRCA1 in S-phase and G2-phase checkpoints after ionizing irradiation. Mol. Cell. Biol. 21, 3445–3450 (2001).

  11. 11.

    et al. Association of BRCA1 with the hRad50-hMre11-p95 complex and the DNA damage response. Science 285, 747–750 (1999).

  12. 12.

    et al. BRCA1 effects on the cell cycle and the DNA damage response are linked to altered gene expression. J. Biol. Chem. 275, 2777–2785 (2000).

  13. 13.

    et al. G2 delay induced by nitrogen mustard in human cells affects cyclin A/Cdk2 and cyclin B1/Cdc2-kinase complexes differently. J. Biol. Chem. 268, 8298–8308 (1993).

  14. 14.

    , & Cdc2 tyrosine phosphorylation is required for the DNA damage checkpoint in fission yeast. Genes Dev. 11, 504–511 (1997).

  15. 15.

    et al. Cdc25+ encodes a protein phosphatase that dephosphorylates p34cdc2. Mol. Biol. Cell 3, 73–84 (1992).

  16. 16.

    , & Purification of a serine kinase that associates with and phosphorylates human Cdc25C on serine 216. J. Biol. Chem. 269, 30461–30469 (1994).

  17. 17.

    , & Cdc25 mitotic inducer targeted by Chk1 DNA damage checkpoint kinase. Science 277, 1495–1497 (1997).

  18. 18.

    et al. Conservation of the Chk1 checkpoint pathway in mammals: linkage of DNA damage to Cdk regulation through Cdc25. Science 277, 1497–1501 (1997).

  19. 19.

    et al. Mitotic and G2 checkpoint control: regulation of 14-3-3 protein binding by phosphorylation of Cdc25C on serine-216. Science 277, 1501–1505 (1997).

  20. 20.

    et al. 14-3-3σ is a p53-regulated inhibitor of G2/M progression. Mol. Cell 1, 3–11 (1997).

  21. 21.

    , & Linkage of ATM to cell cycle regulation by the Chk2 protein kinase. Science 282, 1893–1897 (1998).

  22. 22.

    et al. Centrosome amplification and a defective G2-M cell cycle checkpoint induce genetic instability in BRCA1 exon 11 isoform-deficient cells. Mol. Cell 3, 389–395 (1999).

  23. 23.

    et al. Genetic interactions between tumor suppressors BRCA1 and TP53 in apoptosis, cell cycle and tumorigenesis. Nature Genet. 28, 266–271 (2001).

  24. 24.

    & Distinct roles for cyclin-dependent kinases in cell cycle control. Science 262, 2050–2054 (1993).

  25. 25.

    & BRCA1 interacts with components of the histone deacetylase complex. Proc. Natl Acad. Sci. USA 96, 4983–4988 (1999).

Download references

Acknowledgements

We thank Y. Pommier for the GST–Cdc25C plasmid, C. Smythe for the Chk2 antibody, Y. Shiloh for AT cells, S. Anderson and M. Kirby for flow cytometry, A. Dutra for help with confocal microscopy, E. Sausville and the Drug Synthesis and Chemistry Branch, Developmental Therapeutics Program, Division of Cancer Treatment and Diagnosis at the National Cancer Institute for providing UCN-01; and P. Liu and S. Danoff for comments on the manuscript.

Author information

Affiliations

  1. Genome Technology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.

    • Ronit I. Yarden
    • , Sherly Pardo-Reoyo
    •  & Lawrence C. Brody
  2. Eppley Institute for Cancer Research, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.

    • Magda Sgagias
    •  & Kenneth H. Cowan

Authors

  1. Search for Ronit I. Yarden in:

  2. Search for Sherly Pardo-Reoyo in:

  3. Search for Magda Sgagias in:

  4. Search for Kenneth H. Cowan in:

  5. Search for Lawrence C. Brody in:

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Lawrence C. Brody.

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/ng837

Further reading