v-Src inhibits the interaction between Rad17 and Rad9 and induces replication fork collapse

Cell Biology International

et al. 2015

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Progression of DNA replication is tightly controlled by replication checkpoints to ensure the accurate and rapid duplication of genetic information. Upon replication stress, the replication checkpoint slows global DNA replication by inhibiting the late-firing origins and by slowing replication fork progression. Activation of the replication checkpoint has been studied in depth; however, little is known about the termination of the replication checkpoint. Here, we show that Src family kinases promote the recovery from replication checkpoints. shRNA knockdown of a Src family kinase, Lyn, and acute chemical inhibition of Src kinases prevented inactivation of Chk1 after removal of replication stress. Consistently, Src inhibition slowed resumption of DNA replication, after the removal of replication blocks. The effect of Src inhibition was not observed in the presence of an ATM/ATR inhibitor caffeine. These data indicate that Src kinases promote the resumption of DNA replication by suppressing ATR-dependent replication checkpoints. Surprisingly, the resumption of replication was delayed by caffeine. In addition, Src inhibition delayed recovery from replication fork collapse. We propose that Src kinases maintain the balance between replication stress and the activity of the replication checkpoint.

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Section: Discussionmentioning

confidence: 86%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 98%

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Src family kinases maintain the balance between replication stress and the replication checkpoint

Miura

Cell Biology International

et al. 2015

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Imatinib inhibits inactivation of the ATM/ATR signaling pathway and recovery from adriamycin/doxorubicin‐induced DNA damage checkpoint arrest

Cell Biology International

Kubota

et al. 2015

The DNA damage checkpoint arrests cell cycle progression to allow time for DNA repair. After completion of DNA repair, checkpoint activation is terminated, and cell cycle progression is resumed in a process called checkpoint recovery. The activation of the checkpoint has been studied in depth, but little is known about recovery from the DNA damage checkpoint. Recently we showed that Src family kinases promote recovery from the G2 DNA damage checkpoint. Here we show that imatinib inhibits inactivation of ATM/ATR signaling pathway to suppress recovery from Adriamycin/doxorubicin-induced DNA damage checkpoint arrest. Imatinib and pazopanib, two distinct inhibitors of PDGFR/c-Kit family kinases, delayed recovery from checkpoint arrest and inhibited the subsequent S-G2-M transition after Adriamycin exposure. By contrast, imatinib and pazopanib did not delay the recovery from checkpoint arrest in the presence of an ATM/ATR inhibitor caffeine. Consistently, imatinib induced a persistent activation of ATR-Chk1 signaling. By the way, the maintenance of G2 checkpoint arrest is largely dependent on ATR-Chk1 signaling. However, unlike Src inhibition, imatinib did not delay the recovery from checkpoint arrest in the presence of an ATM inhibitor KU-55933. Furthermore, imatinib induced a persistent activation of ATM-KAP1 signaling, and a possible involvement of imatinib in an ATM-dependent DNA damage response is suggested. These results reveal that imatinib inhibits recovery from Adriamycin-induced DNA damage checkpoint arrest in an ATM/ATR-dependent manner and raise the possibility that imatinib may inhibit resumption of tumor proliferation after chemo- and radiotherapy.

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Lyn tyrosine kinase promotes silencing of ATM-dependent checkpoint signaling during recovery from DNA double-strand breaks

Kuki

Biochemical and Biophysical Research Communications

et al. 2014