title: Proteolysis of a nucleotide excision repair protein by the 26 S proteasome.
abstract: The 26 S proteasome degrades a broad spectrum of proteins and interacts with several nucleotide excision repair (NER) proteins, including the complex of Rad4 and Rad23 that binds preferentially to UV-damaged DNA. The rate of NER is increased in yeast strains with mutations in genes encoding subunits of the 26 S proteasome, indicating that it could negatively regulate a repair process. The specific function of the 26 S proteasome in DNA repair is unclear. It might degrade DNA repair proteins after repair is completed or act as a molecular chaperone to promote the assembly or disassembly of the repair complex. In this study, we show that Rad4 is ubiquitylated and that Rad23 can control this process. We also find that ubiquitylated Rad4 is degraded by the 26 S proteasome. However, the interaction of Rad23 with Rad4 is not only to control degradation of Rad4, but also to assist in assembling the NER incision complex at UV-induced cyclobutane pyrimidine dimers. We speculate that, following the completion of DNA repair, specific repair proteins might be degraded by the proteasome to regulate repair.
authors.affiliation: Susan Lehman Cullman Laboratory for Cancer Research, Department of Chemical Biology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, 164 Frelinghuysen Road, Piscataway 08854-8020, USA.
authors.forename: Lori
authors.initials: L
authors.lastname: Lommel
authors.forename: Tatiana
authors.initials: T
authors.lastname: Ortolan
authors.forename: Li
authors.initials: L
authors.lastname: Chen
authors.forename: Kiran
authors.initials: K
authors.lastname: Madura
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Sweder
mesh_terms: D011088:DNA Ligases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005656:Fungal Proteins / Q000378:metabolism*; D009154:Mutation; D010447:Peptide Hydrolases / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C490846:RAD23 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease; D011088:DNA Ligases