1. Experimental design, validation and computational modeling uncover DNA damage sensing by DNA-PK and ATM.
- Author
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Flassig RJ, Maubach G, Täger C, Sundmacher K, and Naumann M
- Subjects
- Animals, Chromones pharmacology, DNA Damage drug effects, DNA Damage radiation effects, DNA Repair drug effects, DNA-Activated Protein Kinase antagonists & inhibitors, Dogs, Madin Darby Canine Kidney Cells, Models, Molecular, Morpholines pharmacology, Phosphorylation, Pyrones pharmacology, Radiation, Ionizing, Ataxia Telangiectasia Mutated Proteins metabolism, DNA-Activated Protein Kinase metabolism, Histones metabolism
- Abstract
Reliable and efficient detection of DNA damage constitutes a vital capability of human cells to maintain genome stability. Following DNA damage, the histone variant H2AX becomes rapidly phosphorylated by the DNA damage response kinases DNA-PKcs and ATM. H2AX phosphorylation plays a central role in signal amplification leading to chromatin remodeling and DNA repair initiation. The contribution of DNA-PKcs and ATM to H2AX phosphorylation is however puzzling. Although ATM is required, DNA-PKcs can substitute for it. Here we analyze the interplay between DNA-PKcs and ATM with a computational model derived by an iterative workflow: switching between experimental design, experiment and model analysis, we generated an extensive set of time-resolved data and identified a conclusive dynamic signaling model out of several alternatives. Our work shows that DNA-PKcs and ATM enforce a biphasic H2AX phosphorylation. DNA-PKcs can be associated to the initial, and ATM to the succeeding phosphorylation phase of H2AX resulting into a signal persistence detection function for reliable damage sensing. Further, our model predictions emphasize that DNA-PKcs inhibition significantly delays H2AX phosphorylation and associated DNA repair initiation.
- Published
- 2014
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