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bioRxiv · 10.1101/2023.02.02.526879

ATM phosphorylates the FATC domain of DNA-PKcs at threonine 4102 to promote non-homologous end joining

Lu, H.·Zhang, Q.·Laverty, D. J.·Puncheon, A. C.·Williams, G. J.·Nagel, Z. D.·Chen, B. P.·Davis, A. J.
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Abstract

Ataxia-telangiectasia mutated (ATM) drives the DNA damage response via modulation of multiple signal transduction and DNA repair pathways. Previously, ATM activity was implicated in promoting the non-homologous end joining (NHEJ) pathway to repair a subset of DNA double strand breaks (DSBs), but how ATM performs this function is still unclear. In this study, we identified that ATM phosphorylates the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a core NHEJ factor, at its extreme C-terminus at threonine 4102 (T4102) in response to DSBs. Phosphorylation at T4102 stabilizes the interaction between DNA-PKcs and the Ku-DNA complex and promotes assembly and stabilization of the NHEJ machinery at DSBs. Ablating phosphorylation at this site results in decreased NHEJ, radiosensitivity, and increased radiation-induced genomic instability. Collectively, these findings establish a key role for ATM in NHEJ-dependent repair of DSBs through positive regulation of DNA-PKcs.

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Lu, H., Zhang, Q., Laverty, D. J., Puncheon, A. C., Williams, G. J., Nagel, Z. D., Chen, B. P., Davis, A. J.. 2023-02-02. ATM phosphorylates the FATC domain of DNA-PKcs at threonine 4102 to promote non-homologous end joining. https://doi.org/10.1101/2023.02.02.526879

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