Chk1 phosphorylation at Ser286 and Ser301 occurs with both stalled DNA replication and damage checkpoint stimulation
- Division of Biochemistry, Aichi Cancer Center Research Institute, Nagoya, Aichi 464-8681 (Japan)
- Virology Division, National Cancer Center Research Institute, Chuo-ku, Tokyo 104-0045 (Japan)
- Division of Molecular and Cell Biology, Shigei Medical Research Institute, Okayama, Okayama 701-0202 (Japan)
- Department of Nephro-urology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi 467-8601 (Japan)
- Department of Geriatric and Environmental Dermatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi 467-8601 (Japan)
We previously reported Chk1 to be phosphorylated at Ser286 and Ser301 by cyclin-dependent kinase (Cdk) 1 during mitosis [T. Shiromizu et al., Genes Cells 11 (2006) 477-485]. Here, we demonstrated that Chk1-Ser286 and -Ser301 phosphorylation also occurs in hydroxyurea (HU)-treated or ultraviolet (UV)-irradiated cells. Unlike the mitosis case, however, Chk1 was phosphorylated not only at Ser286 and Ser301 but also at Ser317 and Ser345 in the checkpoint response. Treatment with Cdk inhibitors diminished Chk1 phosphorylation at Ser286 and Ser301 but not at Ser317 and Ser345 with the latter. In vitro analyses revealed Ser286 and Ser301 on Chk1 to serve as two major phosphorylation sites for Cdk2. Immunoprecipitation analyses further demonstrated that Ser286/Ser301 and Ser317/Ser345 phosphorylation occur in the same Chk1 molecule during the checkpoint response. In addition, Ser286/Ser301 phosphorylation by Cdk2 was observed in Chk1 mutated to Ala at Ser317 and Ser345 (S317A/S345A), as well as Ser317/Ser345 phosphorylation by ATR was in S286A/S301A. Therefore, Chk1 phosphorylation in the checkpoint response is regulated not only by ATR but also by Cdk2.
- OSTI ID:
- 21255809
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 377, Issue 4; Other Information: DOI: 10.1016/j.bbrc.2008.10.119; PII: S0006-291X(08)02129-3; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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