title: Budding yeast Dsk2 protein forms a homodimer via its C-terminal UBA domain.
abstract: Budding yeast Dsk2 is a family of UbL-UBA proteins that can interact with both polyubiquitin and the proteasome, and is thereby thought to function as a shuttle protein in the ubiquitin-proteasome pathway. Here we show that Dsk2 can homodimerize via its C-terminal UBA domain in the absence of ubiquitin. Dsk2 mutants defective in the UBA domain do not dimerize and do not bind polyubiquitin. The expression of Dsk2 UBA mutants fails to restore the growth defect caused by DSK2 disruption although that of wild-type Dsk2 can restore the defect. These results suggest that Dsk2 homodimerization via the UBA domain plays a role in regulating polyubiquitin binding in the ubiquitin-proteasome pathway.
authors.affiliation: Department of Molecular Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Sasaki
authors.forename: Minoru
authors.initials: M
authors.lastname: Funakoshi
authors.forename: Jane A
authors.initials: JA
authors.lastname: Endicott
authors.forename: Hideki
authors.initials: H
authors.lastname: Kobayashi
mesh_terms: D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D019281:Dimerization; D046988:Proteasome Endopeptidase Complex / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*; D025801:Ubiquitin / Q000737:chemistry* / Q000378:metabolism*; D014452:Ubiquitins / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; C100415:DSK2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D025801:Ubiquitin; D014452:Ubiquitins; D046988:Proteasome Endopeptidase Complex