title: Amino-terminal dimerization, NRDP1-rhodanese interaction, and inhibited catalytic domain conformation of the ubiquitin-specific protease 8 (USP8).
abstract: Ubiquitin-specific protease 8 (USP8) hydrolyzes mono and polyubiquitylated targets such as epidermal growth factor receptors and is involved in clathrin-mediated internalization. In 1182 residues, USP8 contains multiple domains, including coiled-coil, rhodanese, and catalytic domains. We report the first high-resolution crystal structures of these domains and discuss their implications for USP8 function. The amino-terminal domain is a homodimer with a novel fold. It is composed of two five-helix bundles, where the first helices are swapped, and carboxyl-terminal helices are extended in an antiparallel fashion. The structure of the rhodanese domain, determined in complex with the E3 ligase NRDP1, reveals the canonical rhodanese fold but with a distorted primordial active site. The USP8 recognition domain of NRDP1 has a novel protein fold that interacts with a conserved peptide loop of the rhodanese domain. A consensus sequence of this loop is found in other NRDP1 targets, suggesting a common mode of interaction. The structure of the carboxyl-terminal catalytic domain of USP8 exhibits the conserved tripartite architecture but shows unique traits. Notably, the active site, including the ubiquitin binding pocket, is in a closed conformation, incompatible with substrate binding. The presence of a zinc ribbon subdomain near the ubiquitin binding site further suggests a polyubiquitin-specific binding site and a mechanism for substrate induced conformational changes.
authors.affiliation: Structural Genomics Consortium and the Department of Physiology, University of Toronto, Toronto, Ontario M5G 1L5, Canada.
authors.forename: George V
authors.initials: GV
authors.lastname: Avvakumov
authors.forename: John R
authors.initials: JR
authors.lastname: Walker
authors.forename: Sheng
authors.initials: S
authors.lastname: Xue
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Finerty
authors.forename: Farrell
authors.initials: F
authors.lastname: Mackenzie
authors.forename: Elena M
authors.initials: EM
authors.lastname: Newman
authors.forename: Sirano
authors.initials: S
authors.lastname: Dhe-Paganon
mesh_terms: D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D019281:Dimerization; D010450:Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008958:Models, Molecular; D046912:Multiprotein Complexes; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055672:Static Electricity; D013884:Thiosulfate Sulfurtransferase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D043222:Ubiquitin Thiolesterase; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D046912:Multiprotein Complexes; D011994:Recombinant Proteins; C452580:RNF41 protein, human; D044767:Ubiquitin-Protein Ligases; D013884:Thiosulfate Sulfurtransferase; D010450:Endopeptidases; C541534:USP8 protein, human; D043222:Ubiquitin Thiolesterase; C091939:ubiquitin isopeptidase