Iduna is a poly(ADP-ribose) (PAR)-dependent E3 ubiquitin ligase that regulates DNA damage

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 108; no. 34; pp. 14103 - 14108
• Main Authors: Kang, Ho Chul, Lee, Yun-Il, Shin, Joo-Ho, Andrabi, Shaida A, Chi, Zhikai, Gagné, Jean-Philippe, Lee, Yunjong, Ko, Han Seok, Lee, Byoung Dae, Poirier, Guy G, Dawson, Valina L, Dawson, Ted M
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 23.08.2011; National Acad Sciences
• Subjects: Antibodies; binding proteins; binding sites; Biological Sciences; Carrier proteins; Cell cycle; Cell death; Cell Line, Tumor; Cell lines; Cell survival; cell viability; Cells; Comet assay; Cytoprotection; DNA; DNA Damage; DNA repair; gamma radiation; Gene expression regulation; genes; Histones; Humans; Mutation; nucleolin; photosynthetically active radiation; Point mutation; Poly Adenosine Diphosphate Ribose - metabolism; poly(ADP-ribose) polymerase 1; Poly(ADP-ribose) Polymerases - metabolism; Proteasome Endopeptidase Complex - metabolism; proteasomes; Protein Binding; protein degradation; Protein Processing, Post-Translational; protein purification; Protein Structure, Tertiary; Proteins; Quality control; Substrate Specificity; Ubiquitin; Ubiquitin - metabolism; Ubiquitin-protein ligase; Ubiquitin-Protein Ligases - chemistry; Ubiquitin-Protein Ligases - metabolism; Ubiquitination; Ubiquitins; XRCC1 protein
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1108799108

Ubiquitin mediated protein degradation is crucial for regulation of cell signaling and protein quality control. Poly(ADP-ribose) (PAR) is a cell-signaling molecule that mediates changes in protein function through binding at PAR binding sites. Here we characterize the PAR binding protein, Iduna, and show that it is a PAR-dependent ubiquitin E3 ligase. Iduna’s E3 ligase activity requires PAR binding because point mutations at Y156A and R157A eliminate Iduna’s PAR binding and Iduna’s E3 ligase activity. Iduna’s E3 ligase activity also requires an intact really interesting new gene (RING) domain because Iduna possessing point mutations at either H54A or C60A is devoid of ubiquitination activity. Tandem affinity purification reveals that Iduna binds to a number of proteins that are either PARsylated or bind PAR including PAR polymerase-1, 2 (PARP1, 2), nucleolin, DNA ligase III, KU70, KU86, XRCC1, and histones. PAR binding to Iduna activates its E3 ligase function, and PAR binding is required for Iduna ubiquitination of PARP1, XRCC1, DNA ligase III, and KU70. Iduna’s PAR-dependent ubiquitination of PARP1 targets it for proteasomal degradation. Via PAR binding and ubiquitin E3 ligase activity, Iduna protects against cell death induced by the DNA damaging agent N-methyl-N-nitro-N-nitrosoguanidine (MNNG) and rescues cells from G1 arrest and promotes cell survival after γ-irradiation. Moreover, Iduna facilitates DNA repair by reducing apurinic/apyrimidinic (AP) sites after MNNG exposure and facilitates DNA repair following γ-irradiation as assessed by the comet assay. These results define Iduna as a PAR-dependent E3 ligase that regulates cell survival and DNA repair.