DNA Double-Strand Break Formation upon UV-Induced Replication Stress Activates ATM and DNA-PKcs Kinases

JOURNAL OF MOLECULAR BIOLOGY

卷:385

Article

Yajima, Hrohiko¹  Lee, Kyung-Jong¹  Zhang, Shichuan¹  Kobayashi, Junya²  Chen, Benjamin P. C.¹ 

[1] Univ Texas SW Med Ctr Dallas, Dept Radiat Oncol, Div Mol Radiat Biol, Dallas, TX 75390 USA

[2] Kyoto Univ, Ctr Radiat Biol, Dept Genome Dynam, Kyoto 6068501, Japan

关键词: UV;    replication stress;    DNA double-strand breaks;    ATM;    DNA-PKcs;   

DOI  :  10.1016/j.jmb.2008.11.036

来源: Elsevier

【 摘 要 】

The phosphatidylinositol 3-kinase-like protein kinases, including ATM (ataxia-telangiectasia mutated), ATR (ataxia-telangiectasia and Rad3 related), and DNA-PKcs (DNA-dependent protein kinase catalytic subunit), are the main kinases activated following various assaults on DNA. Although ATM and DNA-PKcs kinases are activated upon DNA double-strand breaks, evidence suggests that these kinases are rapidly phosphorylated by ATR kinase upon UV irradiation; thus, these kinases may also participate in the response to replication stress. Using UV-induced replication stress, we further characterize whether ATM and DNA-PKcs kinase activities are also involved in the cellular response. Contrary to the rapid activation of the ATR-dependent pathway, ATM-dependent Chk2 and KAP-1 phosphorylations, as well as DNA-PKcs Ser2056 autophosphorylation, reach their peak level at 4 to 8 h after UV irradiation. The delayed kinetics of ATM- and DNA-PKcs-dependent phosphorylations also correlated with a surge in H2AX phosphorylation, suggesting that double-strand break formation resulting from collapse of replication forks is responsible for the activation of ATM and DNA-PKcs kinases. In addition, we observed that some phosphorylation events initiated by ATR kinase in the response to UV were mediated by ATM at a later phase of the response. Furthermore, the S-phase checkpoint after UV irradiation was defective in ATM-deficient cells. These results suggest that the late increase of ATM activity is needed to complement the decreasing ATR activity for maintaining a vigilant checkpoint regulation upon replication stress. (C) 2008 Elsevier Ltd. All rights reserved.

【 授权许可】

Free