title: Identification of SUMO modification sites in the base excision repair protein, Ntg1.
abstract: DNA damaging agents are a constant threat to genomes in both the nucleus and the mitochondria. To combat this threat, a suite of DNA repair pathways cooperate to repair numerous types of DNA damage. If left unrepaired, these damages can result in the accumulation of mutations which can lead to deleterious consequences including cancer and neurodegenerative disorders. The base excision repair (BER) pathway is highly conserved from bacteria to humans and is primarily responsible for the removal and subsequent repair of toxic and mutagenic oxidative DNA lesions. Although the biochemical steps that occur in the BER pathway have been well defined, little is known about how the BER machinery is regulated. The budding yeast, Saccharomyces cerevisiae is a powerful model system to biochemically and genetically dissect BER. BER is initiated by DNA N-glycosylases, such as S. cerevisiae Ntg1. Previous work demonstrates that Ntg1 is post-translationally modified by SUMO in response to oxidative DNA damage suggesting that this modification could modulate the function of Ntg1. In this study, we mapped the specific sites of SUMO modification within Ntg1 and identified the enzymes responsible for sumoylating/desumoylating Ntg1. Using a non-sumoylatable version of Ntg1, ntg1ΔSUMO, we performed an initial assessment of the functional impact of Ntg1 SUMO modification in the cellular response to DNA damage. Finally, we demonstrate that, similar to Ntg1, the human homologue of Ntg1, NTHL1, can also be SUMO-modified in response to oxidative stress. Our results suggest that SUMO modification of BER proteins could be a conserved mechanism to coordinate cellular responses to DNA damage.
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States; Graduate Program in Genetics and Molecular Biology, Emory University School of Medicine, Atlanta, GA 30322, United States.
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Swartzlander
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States; Graduate Program in Genetics and Molecular Biology, Emory University School of Medicine, Atlanta, GA 30322, United States.
authors.forename: Annie J
authors.initials: AJ
authors.lastname: McPherson
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States.
authors.forename: Harry R
authors.initials: HR
authors.lastname: Powers
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States; Graduate Program in Cancer Biology, Emory University School of Medicine, Atlanta, GA 30322, United States.
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Limpose
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States; Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University School of Medicine, Atlanta, GA 30322, United States.
authors.forename: Emily G
authors.initials: EG
authors.lastname: Kuiper
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States; Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, United States.
authors.forename: Natalya P
authors.initials: NP
authors.lastname: Degtyareva
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States; Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, United States. Electronic address: acorbe2@emory.edu.
authors.forename: Anita H
authors.initials: AH
authors.lastname: Corbett
authors.affiliation: Department of Biochemistry, Emory University School of Medicine, Atlanta, GA 30322, United States; Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA 30322, United States; Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA 30322, United States; Department of Hematology and Medical Oncology Emory University School of Medicine, Atlanta, GA 30322, United States. Electronic address: medpwd@emory.edu.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Doetsch
mesh_terms: D004249:DNA Damage; D004260:DNA Repair; D004271:DNA, Fungal / Q000235:genetics / Q000378:metabolism; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000235:genetics* / Q000378:metabolism; D043224:Deoxyribonuclease (Pyrimidine Dimer) / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008698:Mesylates / Q000494:pharmacology; D008958:Models, Molecular; D010449:Peptide Mapping; D000072417:Protein Domains; D011499:Protein Processing, Post-Translational; D017433:Protein Structure, Secondary; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D058207:Sumoylation
chemical_list: D004271:DNA, Fungal; D008698:Mesylates; D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; D029701:Saccharomyces cerevisiae Proteins; C045880:methanesulfonic acid; D006861:Hydrogen Peroxide; D043224:Deoxyribonuclease (Pyrimidine Dimer); C468347:NTHL1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C101825:NTG1 protein, S cerevisiae
keywords: Base excision repair (BER); NTHL1; Ntg1; SUMO; Sumoylation