Inhibition of Human Chk1 Causes Increased Initiation of DNA Replication, Phosphorylation of ATR Targets, and DNA Breakage
| Autor: | Claus Storgaard Sørensen, Maxwell Sehested, Kasper Fugger, Fredrik Johansson, Jiri Bartek, Thomas Helleday, Jiri Lukas, Lasse Tengbjerg Hansen, Randi G. Syljuåsen, Cecilia Lundin |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
DNA Replication
DNA re-replication animal structures Chromosomal Proteins Non-Histone DNA repair Gene Expression DNA Single-Stranded Cell Cycle Proteins Eukaryotic DNA replication Ataxia Telangiectasia Mutated Proteins Protein Serine-Threonine Kinases Biology environment and public health Histones Replication factor C Caffeine Replication Protein A Roscovitine Humans CHEK1 Phosphorylation RNA Small Interfering Protein Kinase Inhibitors Molecular Biology Replication protein A DNA replication Cell Biology Staurosporine Molecular biology DNA-Binding Proteins Checkpoint Kinase 2 enzymes and coenzymes (carbohydrates) Purines Replication Initiation Checkpoint Kinase 1 Tumor Suppressor Protein p53 biological phenomena cell phenomena and immunity Protein Kinases DNA Damage |
| Zdroj: | Karolinska Institutet |
| ISSN: | 1098-5549 |
| DOI: | 10.1128/mcb.25.9.3553-3562.2005 |
| Popis: | Human checkpoint kinase 1 (Chk1) is an essential kinase required to preserve genome stability. Here, we show that Chk1 inhibition by two distinct drugs, UCN-01 and CEP-3891, or by Chk1 small interfering RNA (siRNA) leads to phosphorylation of ATR targets. Chk1-inhibition triggered rapid, pan-nuclear phosphorylation of histone H2AX, p53, Smc1, replication protein A, and Chk1 itself in human S-phase cells. These phosphorylations were inhibited by ATR siRNA and caffeine, but they occurred independently of ATM. Chk1 inhibition also caused an increased initiation of DNA replication, which was accompanied by increased amounts of nonextractable RPA protein, formation of single-stranded DNA, and induction of DNA strand breaks. Moreover, these responses were prevented by siRNA-mediated downregulation of Cdk2 or the replication initiation protein Cdc45, or by addition of the CDK inhibitor roscovitine. We propose that Chk1 is required during normal S phase to avoid aberrantly increased initiation of DNA replication, thereby protecting against DNA breakage. These results may help explain why Chk1 is an essential kinase and should be taken into account when drugs to inhibit this kinase are considered for use in cancer treatment. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|