title: The stress-activated protein kinases p38α/β and JNK1/2 cooperate with Chk1 to inhibit mitotic entry upon DNA replication arrest.
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 G 2/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, thereby 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.
authors.affiliation: Departament de Biologia Cel·lular, Immunologia i Neurociències, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Alba
authors.initials: A
authors.lastname: Llopis
authors.forename: Noelia
authors.initials: N
authors.lastname: Salvador
authors.forename: Amaia
authors.initials: A
authors.lastname: Ercilla
authors.forename: Sandra
authors.initials: S
authors.lastname: Guaita-Esteruelas
authors.forename: Ivan del Barco
authors.initials: Idel B
authors.lastname: Barrantes
authors.forename: Jalaj
authors.initials: J
authors.lastname: Gupta
authors.forename: Matthias
authors.initials: M
authors.lastname: Gaestel
authors.forename: Roger J
authors.initials: RJ
authors.lastname: Davis
authors.forename: Angel R
authors.initials: AR
authors.lastname: Nebreda
authors.forename: Neus
authors.initials: N
authors.lastname: Agell
mesh_terms: D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism; D000071877:Checkpoint Kinase 1; D056744:Cyclin B1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D004247:DNA / Q000096:biosynthesis; D004261:DNA Replication / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology; D004789:Enzyme Activation / Q000187:drug effects; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D006918:Hydroxyurea / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D007700:Kinetics; D048371:MAP Kinase Kinase 3 / Q000378:metabolism; D048669:MAP Kinase Kinase 6 / Q000378:metabolism; D051379:Mice; D048290:Mitogen-Activated Protein Kinase 11 / Q000378:metabolism*; D048308:Mitogen-Activated Protein Kinase 14 / Q000378:metabolism*; D008938:Mitosis; D041681:NIH 3T3 Cells; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D016196:S Phase / Q000187:drug effects; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D056744:Cyclin B1; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; D016590:Aphidicolin; D004247:DNA; D011494:Protein Kinases; C576897:Atr protein, mouse; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D000071877:Checkpoint Kinase 1; C000605869:Chek1 protein, mouse; D017346:Protein Serine-Threonine Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D048290:Mitogen-Activated Protein Kinase 11; D048308:Mitogen-Activated Protein Kinase 14; D048371:MAP Kinase Kinase 3; D048669:MAP Kinase Kinase 6; C482531:Map2k3 protein, mouse; C482567:Map2k6 protein, mouse; D006918:Hydroxyurea