| First Author | Yajima H | Year | 2009 |
| Journal | J Mol Biol | Volume | 385 |
| Issue | 3 | Pages | 800-10 |
| PubMed ID | 19071136 | Mgi Jnum | J:168938 |
| Mgi Id | MGI:4939321 | Doi | 10.1016/j.jmb.2008.11.036 |
| Citation | Yajima H, et al. (2009) DNA double-strand break formation upon UV-induced replication stress activates ATM and DNA-PKcs kinases. J Mol Biol 385(3):800-10 |
| abstractText | 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. |
