Budding yeast Dsk2p is a polyubiquitin-binding protein that can interact with the proteasome.
Dsk2p from Saccharomyces cerevisiae belongs to the class of proteins that contain a ubiquitin-like (UbL) domain at the N terminus together with a ubiquitin-associated (UBA) domain at the C terminus. We show here that the C-terminal UBA domain of Dsk2p binds to K48-linked polyubiquitin chains, and the N-terminal UbL domain of Dsk2p interacts with the proteasome. Overexpression of Dsk2p caused the accumulation of large amounts of polyubiquitin, and extragenic suppressors of the Dsk2p-mediated lethality proved to be temperature-sensitive mutations in two proteasome subunits, rpn1 and pre2. K48-linked ubiquitin-dependent degradation was impaired by disruption of the DSK2 gene. These results indicate that Dsk2p is K48-linked polyubiquitin-binding protein and also interacts with the proteasome. We discuss a possible role of adaptor function of Dsk2p via its UbL and UBA domains in the ubiquitin-proteasome pathway.
Funakoshi
Minoru
M
Department of Molecular Biology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan.
Sasaki
Toru
T
Nishimoto
Takeharu
T
Kobayashi
Hideki
H
D001665:Binding Sites; D018797:Cell Cycle Proteins; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D016153:Genes, Suppressor; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D046988:Proteasome Endopeptidase Complex; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D020798:Two-Hybrid System Techniques; D014452:Ubiquitins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C100415:DSK2 protein, S cerevisiae; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D021122:Protein Subunits; D011506:Proteins; C490846:RAD23 protein, S cerevisiae; C499663:RPN1 protein, S cerevisiae; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D003546:Cysteine Endopeptidases; C080044:PRE2 protein, S cerevisiae; D046988:Proteasome Endopeptidase Complex