This Article Full Text Full Text (PDF) Supplemental material Other Versions of this Article: MCB.01611-06v1 27/7/2572    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Niida, H. Articles by Nakanishi, M. Search for Related Content PubMed PubMed Citation Articles by Niida, H. Articles by Nakanishi, M.

 Previous Article  |  Next Article 

Molecular and Cellular Biology, April 2007, p. 2572-2581, Vol. 27, No. 7
0270-7306/07/$08.00+0     doi:10.1128/MCB.01611-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Specific Role of Chk1 Phosphorylations in Cell Survival and Checkpoint Activation ^,

Department of Biochemistry and Cell Biology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-ku, Mizuho-cho, Nagoya 467-8601, Japan,¹ Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore²

Received 29 August 2006/ Returned for modification 2 October 2006/ Accepted 3 January 2007

Chk1 is a multifunctional protein kinase that plays essential roles in cell survival and cell cycle checkpoints. Chk1 is phosphorylated at multiple sites by several protein kinases, but the precise effects of these phosphorylations are largely unknown. Using a knockout-knockin system, we examined the abilities of Chk1 mutants to reverse the defects of Chk1-null cells. Wild-type Chk1 could rescue all the defects of Chk1-null cells. Like endogenous Chk1, wild-type Chk1 localized in both the cytoplasm and the nucleus, and its centrosomal association was enhanced by DNA damage. The mutation at S345 resulted in mitotic catastrophe, impaired checkpoints, and loss of the ability to localize in the cytoplasm, but the mutant retained the ability to be released from chromatin upon encountering genotoxic stressors. In contrast, the mutation at S317 resulted in impaired checkpoints and loss of chromatin release upon encountering genotoxic stressors, but its mutant retained the abilities to prevent mitotic catastrophes and to localize in the cytoplasm, suggesting the distinct effects of these phosphorylations. The forced immobilization of S317A/S345A in centrosomes resulted in the prevention of apoptosis in the presence or absence of DNA damage. Thus, two-step phosphorylation of Chk1 at S317 and S345 appeared to be required for proper localization of Chk1 to centrosomes.

Published ahead of print on 22 January 2007.

Supplemental material for this article may be found at http://mcb.asm.org/.

This article has been cited by other articles:

• Ashwell, S., Zabludoff, S. (2008). DNA Damage Detection and Repair Pathways--Recent Advances with Inhibitors of Checkpoint Kinases in Cancer Therapy. Clin. Cancer Res. 14: 4032-4037 [Abstract] [Full Text]  
• Enders, G. H. (2008). Expanded Roles for Chk1 in Genome Maintenance. J. Biol. Chem. 283: 17749-17752 [Abstract] [Full Text]  
• Scorah, J., Dong, M.-Q., Yates, J. R. III, Scott, M., Gillespie, D., McGowan, C. H. (2008). A Conserved Proliferating Cell Nuclear Antigen-interacting Protein Sequence in Chk1 Is Required for Checkpoint Function. J. Biol. Chem. 283: 17250-17259 [Abstract] [Full Text]  
• Guervilly, J.-H., Mace-Aime, G., Rosselli, F. (2008). Loss of CHK1 function impedes DNA damage-induced FANCD2 monoubiquitination but normalizes the abnormal G2 arrest in Fanconi anemia. Hum Mol Genet 17: 679-689 [Abstract] [Full Text]  
• Palii, S. S., Van Emburgh, B. O., Sankpal, U. T., Brown, K. D., Robertson, K. D. (2008). DNA Methylation Inhibitor 5-Aza-2'-Deoxycytidine Induces Reversible Genome-Wide DNA Damage That Is Distinctly Influenced by DNA Methyltransferases 1 and 3B. Mol. Cell. Biol. 28: 752-771 [Abstract] [Full Text]