Mennerich Daniela, Ashok Yashwanth, Vela-Rodríguez Carlos, Hentilä Heli I, Rall-Scharpf Melanie, Wiesmüller Lisa, Prunskaite-Hyyryläinen Renata, Lehtiö Lari, Kietzmann Thomas
Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, Oulu, Finland.
Department of Obstetrics and Gynecology, Ulm University, Ulm, Germany.
iScience. 2025 Jun 24;28(8):112990. doi: 10.1016/j.isci.2025.112990. eCollection 2025 Aug 15.
The DNA damage response (DDR) relies on a complex protein network to maintain genomic integrity, yet the interplay between post-translational modifiers remains poorly understood. Here, we uncover a novel regulatory axis between the E3 ubiquitin ligase DTX3L and the deubiquitinase USP28 at DNA double-strand breaks (DSBs). Our results reveal a sophisticated feedback mechanism in which DTX3L ubiquitinates USP28, leading to its proteasomal degradation, while USP28 counteracts by deubiquitinating both itself and DTX3L. This cross-regulation fine-tunes DSB repair in multiple pathways, including non-homologous end-joining (NHEJ), homologous recombination (HR), single-strand annealing (SSA), and microhomology-mediated end joining (MMEJ). Strikingly, the detrimental effects of USP28 depletion on these repair pathways were rescued by concurrent DTX3L knockdown. Collectively, our work uncovers a novel layer of DDR regulation in which DTX3L and USP28's antagonistic activities calibrate cellular responses to genotoxic stress, thus identifying promising therapeutic targets to combat diseases associated with genomic instability.
DNA损伤反应（DDR）依赖于一个复杂的蛋白质网络来维持基因组完整性，然而翻译后修饰因子之间的相互作用仍知之甚少。在这里，我们揭示了E3泛素连接酶DTX3L和去泛素化酶USP28在DNA双链断裂（DSB）处的一个新的调控轴。我们的结果揭示了一种复杂的反馈机制，其中DTX3L使USP28泛素化，导致其通过蛋白酶体降解，而USP28则通过使自身和DTX3L去泛素化来进行对抗。这种交叉调节在多种途径中微调DSB修复，包括非同源末端连接（NHEJ）、同源重组（HR）、单链退火（SSA）和微同源性介导的末端连接（MMEJ）。引人注目的是，同时敲低DTX3L可挽救USP28缺失对这些修复途径的有害影响。总体而言，我们的工作揭示了DDR调控的一个新层面，其中DTX3L和USP28的拮抗活性校准了细胞对基因毒性应激的反应，从而确定了对抗与基因组不稳定相关疾病的有前景的治疗靶点。
