DNA replication arrest in response to genotoxic stress provokes early activation of stress-activated protein kinases (SAPK/JNK).
The impact of DNA damage-induced replication blockage for early activation of stress kinases [stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK)] is largely unknown. Here, we show that induction of dual phosphorylation of SAPK/JNK by the DNA polymerase inhibitor aphidicolin was not ameliorated by additional exposure to ultraviolet (UV) light, indicating that overlapping mechanisms participate in signaling to SAPK/JNK triggered by both agents. UV-induced DNA replication blockage, cyclobutane pyrimidine dimer formation and DNA strand break induction coincided with SAPK/JNK phosphorylation at early (< or =30 min) but not late (> or =2 h) time points after exposure. Genotoxin-stimulated SAPK/JNK activation was attenuated in nonproliferating cells, indicating that S phase-dependent mechanisms are involved in signaling to SAPK/JNK. Correspondingly, UV-induced phosphorylation of SAPK/JNK was higher in S-phase cells as compared with G(1)-phase cells. Activation of SAPK/JNK by genotoxins was below detection limit in nonproliferating human peripheral blood lymphocytes, whereas peripheral blood lymphocytes stimulated to proliferation displayed clear SAPK/JNK activation. UV-induced phosphorylation of SAPK/JNK was attenuated in XPC-defective cells, ameliorated in BRCA2 mutated cells and not changed in cells lacking ATM, DNA-PK, CSB, XPA, p53, ERCC1 or PARP as compared with the corresponding wild types. Based on these data, we suggest that DNA replication blockage caused by genotoxin-induced DNA damage contributes to early activation of SAPK/JNK.
Damrot
Julia
J
Department of Toxicology, University of Mainz, Mainz, Germany.
Helbig
Lars
L
Roos
Wynand P
WP
Barrantes
Steve Q
SQ
Kaina
Bernd
B
Fritz
Gerhard
G
D000818:Animals; D016590:Aphidicolin / Q000494:pharmacology; D051017:Apoptosis Regulatory Proteins; D024682:BRCA2 Protein / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D006224:Cricetinae; D004249:DNA Damage / Q000502:physiology*; D004261:DNA Replication / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D005347:Fibroblasts / Q000502:physiology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008214:Lymphocytes / Q000201:enzymology; D051379:Mice; D018345:Mice, Knockout; D019384:Nucleic Acid Synthesis Inhibitors; D010766:Phosphorylation; D011740:Pyrimidine Dimers / Q000378:metabolism; D014466:Ultraviolet Rays
D051017:Apoptosis Regulatory Proteins; C118024:BLID protein, human; D024682:BRCA2 Protein; C551750:BRCA2 protein, human; D004268:DNA-Binding Proteins; D019384:Nucleic Acid Synthesis Inhibitors; D011740:Pyrimidine Dimers; D016590:Aphidicolin; D048031:JNK Mitogen-Activated Protein Kinases