C-terminal residues of DNA polymerase β and E3 ligase required for ubiquitin-linked proteolysis of oxidative DNA-protein crosslinks.

Autor: Quiñones JL; Department of Pharmacological Sciences, Stony Brook University School of Medicine, Basic Science Tower 8-140, Stony Brook, New York 11794, USA., Tang M; Department of Pharmacological Sciences, Stony Brook University School of Medicine, Basic Science Tower 8-140, Stony Brook, New York 11794, USA., Fang Q; Mitchell Cancer Institute & Department of Pharmacology, University of South Alabama, Mobile, AL 36604, USA., Sobol RW; Mitchell Cancer Institute & Department of Pharmacology, University of South Alabama, Mobile, AL 36604, USA; Department of Pathology and Laboratory Medicine, Warren Alpert Medical School & Legorreta Cancer Center, Brown University, Providence, RI 02912, USA., Demple B; Department of Pharmacological Sciences, Stony Brook University School of Medicine, Basic Science Tower 8-140, Stony Brook, New York 11794, USA; Department of Radiation Oncology, Renaissance School of Medicine, Stony Brook University, Stony Brook, New York 11794, USA. Electronic address: bruce.demple@stonybrook.edu.
Jazyk: angličtina
Zdroj: DNA repair [DNA Repair (Amst)] 2024 Nov; Vol. 143, pp. 103756. Date of Electronic Publication: 2024 Aug 28.
DOI: 10.1016/j.dnarep.2024.103756
Abstrakt: Free radicals produce in DNA a large variety of base and deoxyribose lesions that are corrected by the base excision DNA repair (BER) system. However, the C1'-oxidized abasic residue 2-deoxyribonolactone (dL) traps DNA repair lyases in covalent DNA-protein crosslinks (DPC), including the core BER enzyme DNA polymerase beta (Polβ). Polβ-DPC are rapidly processed in mammalian cells by proteasome-dependent digestion. Blocking the proteasome causes oxidative Polβ-DPC to accumulate in a ubiquitylated form, and this accumulation is toxic to human cells. In the current study, we investigated the mechanism of Polβ-DPC processing in cells exposed to the dL-inducing oxidant 1,10-copper-ortho-phenanthroline. Alanine substitution of either or both of two Polβ C-terminal residues, lysine-206 and lysine-244, enhanced the accumulation of mutant Polβ-DPC relative to the wild-type protein, and removal of the mutant DPC was diminished. Substitution of the N-terminal lysines 41, 61, and 81 did not affect Polβ-DPC processing. For Polβ with the C-terminal lysine substitutions, the amount of ubiquitin in the stabilized DPC was lowered by ∼40 % relative to wild-type Polβ. Suppression of the HECT domain-containing E3 ubiquitin ligase TRIP12 augmented the formation of oxidative Polβ-DPC and prevented Polβ-DPC removal in oxidant-treated cells. Consistent with the toxicity of accumulated oxidative Polβ-DPC, TRIP12 knockdown increased oxidant-mediated cytotoxicity. Thus, ubiquitylation of lysine-206 and lysine-244 by TRIP12 is necessary for digestion of Polβ-DPC by the proteasome as the rapid first steps of DPC repair to prevent their cytotoxic accumulation. Understanding how DPC formed with Polβ or other AP lyases are repaired in vivo is an important step in revealing how cells cope with the toxic potential of such adducts.
Competing Interests: Declaration of Competing Interest R.W.S. is co-founder of Canal House Biosciences, LLC, is on the Scientific Advisory Board, and has an equity interest. Canal House Biosciences was not involved in the preparation of this study nor of this manuscript. The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
(Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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