Ubiquitin-like proteins and Rpn10 play cooperative roles in ubiquitin-dependent proteolysis.
Rpn10, a subunit of the 26S proteasome, has been proposed to act as a receptor for multiubiquitin chains in ubiquitin-dependent proteolysis. However, studies on RPN10-deleted mutants in yeasts have suggested the presence of other multiubiquitin chain-binding factors functioning in ubiquitin-dependent proteolysis. Here, we report that a mutant with a triple deletion of RAD23, DSK2, and RPN10 genes accumulates large amounts of polyubiquitinated proteins, as is the case with a mutant with RAD23 and DSK2 deletions under restrictive conditions. Dsk2, Rad23, and Rpn10 have different capacities to bind multiubiquitin chains. Another ubiquitin-like protein, Ddi1, has similar activity to those of Rad23 and Dsk2. Taken together, the results suggest that ubiquitin-like proteins, Rad23, Dsk2, possibly Ddi1, and Rpn10 play cooperative roles in ubiquitin-dependent proteolysis, serving as multiubiquitin chain-binding proteins.
Saeki
Yasushi
Y
Department of Biochemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
Saitoh
Aki
A
Toh-e
Akio
A
Yokosawa
Hideyoshi
H
D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009154:Mutation; D010447:Peptide Hydrolases / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins / Q000235:genetics / Q000502:physiology*
D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C108125:DDI1 protein, S cerevisiae; D004268:DNA-Binding Proteins; C100415:DSK2 protein, S cerevisiae; D005656:Fungal Proteins; C490846:RAD23 protein, S cerevisiae; C122019:RPN10 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease