title: Ubiquitin-associated (UBA) domains in Rad23 bind ubiquitin and promote inhibition of multi-ubiquitin chain assembly.
abstract: Rad23 is a DNA repair protein that promotes the assembly of the nucleotide excision repair complex. Rad23 can interact with the 26S proteasome through an N-terminal ubiquitin-like domain, and inhibits the assembly of substrate-linked multi-ubiquitin (multi-Ub) chains in vitro and in vivo. Significantly, Rad23 can bind a proteolytic substrate that is conjugated to a few ubiquitin (Ub) moieties. We report here that two ubiquitin-associated (UBA) domains in Rad23 form non-covalent interactions with Ub. A mutant that lacked either UBA sequence was capable of blocking the assembly of substrate-linked multi-Ub chains, although a mutant that lacked both UBA domains was significantly impaired. These studies suggest that the interaction with Ub is required for Rad23 activity, and that other UBA-containing proteins may have a similar function.
authors.affiliation: Department of Biochemistry, Robert Wood Johnson Medical School-UMDNJ, 675 Hoes Lane, Piscataway, NJ 08854, USA.
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: U
authors.initials: U
authors.lastname: Shinde
authors.forename: T G
authors.initials: TG
authors.lastname: Ortolan
authors.forename: K
authors.initials: K
authors.lastname: Madura
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003062:Codon; D004247:DNA / Q000378:metabolism; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D009841:Oligonucleotides / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D025801:Ubiquitin / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D003062:Codon; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009841:Oligonucleotides; D025801:Ubiquitin; C086985:RAD23A protein, human; D004247:DNA; D005982:Glutathione Transferase; D045643:DNA Repair Enzymes