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Title: The stress-activated protein kinases p38α/β and JNK1/2 cooperate with Chk1 to inhibit mitotic entry upon DNA replication arrest
Author: Llopis, Alba
Salvador, Noelia
Ercilla Eguiarte, Amaia
Guaita-Esteruelas, Sandra
Barco Barrantes, Ivan del
Gupta, Jalaj
Gaestel, Matthias
Davis, Roger J.
Nebreda, Àngel R.
Agell i Jané, Neus
Keywords: Proteïnes quinases
Protein kinases
Issue Date: 1-Oct-2012
Publisher: Landes Bioscience
Abstract: Accurate DNA replication is crucial for the maintenance of genome integrity. To this aim, cells have evolved complex surveillance mechanisms to prevent mitotic entry in the presence of partially replicated DNA. ATR and Chk1 are key elements in the signal transduction pathways of DNA replication checkpoint; however, other kinases also make significant contributions. We show here that the stress kinases p38 and JNK are activated when DNA replication is blocked, and that their activity allows S/M, but not G₂/M, checkpoint maintenance when Chk1 is inhibited. Activation of both kinases by DNA replication inhibition is not mediated by the caffeine-sensitive kinases ATR or ATM. Phosphorylation of MKK3/6 and MKK4, p38 and JNK upstream kinases was also observed upon DNA replication inhibition. Using a genetic approach, we dissected the p38 pathway and showed that both p38α and p38β isoforms collaborate to inhibit mitotic entry. We further defined MKK3/6 and MK2/3 as the key upstream and downstream elements in the p38 signaling cascade after replication arrest. Accordingly, we found that the stress signaling pathways collaborate with Chk1 to keep cyclin B1/Cdk1 complexes inactive when DNA replication is inhibited, there by preventing cell cycle progression when DNA replication is stalled. Our results show a complex response to replication stress, where multiple pathways are activated and fulfill overlapping roles to prevent mitotic entry with unreplicated DNA.
Note: Versió postprint del document publicat a:
It is part of: Cell Cycle, 2012, vol. 11, num. 19, p. 3627-3637
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ISSN: 1538-4101
Appears in Collections:Articles publicats en revistes (Biomedicina)

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