DNA-PK is activated by SIRT2 deacetylation to promote DNA double-strand break repair by non-homologous end joining

• Authors: PamelaSara E. Head, Emory University; Priya Kapoor-Vazirani, Emory University; Purnachandra Ganji, Emory University; Hui Zhang, Emory University; Sandip K. Rath, Emory University; Nho C. Luong, Emory University; Ramona Haji-Seyed-Javadi, Emory University; Fatmata Sesay, Emory University; Shi-Ya Wang, University of Texas Southwestern; Duc M. Duong, Emory University; Waago Daddacha, Augusta University; Elizabeth V. Minten, Emory University; Boying Song, Emory University; Diana Danelia, Emory University; Xu Liu, Emory University; Shuyi Li, Emory University; Eric Ortlund, Emory University; Nicholas Seyfried, Emory University; David M. Smalley, Georgia Institute of Technology; Ya Wang, Emory University; Xingming Deng, Emory University; William Dynan, Emory University; Bassel El-Rayes, University of Alabama Birmingham; Anthony J. Davis, University of Texas Southwestern; David Yu, Emory University
• Journal Title: NUCLEIC ACIDS RESEARCH
• Volume: Volume 51, Number 15
• Publisher: OXFORD UNIV PRESS | 2023-07-03, Pages 7972-7987
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1093/nar/gkad549
• Subjects: Biology, Cell
• Keywords: Science & Technology; Life Sciences & Biomedicine; Biochemistry & Molecular Biology; DEPENDENT PROTEIN-KINASE; CRYO-EM STRUCTURE; CATALYTIC SUBUNIT; PHOSPHORYLATION SITES; IN-VITRO; AUTOPHOSPHORYLATION; COMPLEX; ATM; KU; MUTATIONS

Abstract

DNA-dependent protein kinase (DNA-PK) plays a critical role in non-homologous end joining (NHEJ), the predominant pathway that repairs DNA double-strand breaks (DSB) in response to ionizing radiation (IR) to govern genome integrity. The interaction of the catalytic subunit of DNA-PK (DNA-PKcs) with the Ku70/Ku80 heterodimer on DSBs leads to DNA-PK activation; however, it is not known if upstream signaling events govern this activation. Here, we reveal a regulatory step governing DNA-PK activation by SIRT2 deacetylation, which facilitates DNA-PKcs localization to DSBs and interaction with Ku, thereby promoting DSB repair by NHEJ. SIRT2 deacetylase activity governs cellular resistance to DSB-inducing agents and promotes NHEJ. SIRT2 furthermore interacts with and deacetylates DNA-PKcs in response to IR. SIRT2 deacetylase activity facilitates DNA-PKcs interaction with Ku and localization to DSBs and promotes DNA-PK activation and phosphorylation of downstream NHEJ substrates. Moreover, targeting SIRT2 with AGK2, a SIRT2-specific inhibitor, augments the efficacy of IR in cancer cells and tumors. Our findings define a regulatory step for DNA-PK activation by SIRT2-mediated deacetylation, elucidating a critical upstream signaling event initiating the repair of DSBs by NHEJ. Furthermore, our data suggest that SIRT2 inhibition may be a promising rationale-driven therapeutic strategy for increasing the effectiveness of radiation therapy.