Rpn10p is a receptor for ubiquitinated Gcn4p in proteasomal proteolysis.
GCN4 is a typical eukaryotic transcriptional activator that is implicated in the expression of many genes involved in amino acids and purine biosyntheses under stress conditions. It is degraded by 26S proteasomes following ubiquitination. However, the immediate receptor for ubiquitinated Gcn4p has not yet been identified. We investigated whether ubiquitinated Gcn4p binds directly to Rpn10p as the ubiquitinated substrate receptor of the 26S proteasome. We found that the level of Gcn4p increased in cells deleted for Rpn10p but not in cells deleted for RAD23 and DSK2, the other ubiquitinated substrate receptors and, unlike Rpn10p, neither of these proteins recognized ubiquitinated Gcn4p. These results suggest that Rpn10p is the receptor that binds the polyubiquitin chain during ubiquitin-dependent proteolysis of Gcn4p.
Seong
Ki Moon
KM
School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
Baek
Je-Hyun
JH
Ahn
Byung-Yoon
BY
Yu
Myeong-Hee
MH
Kim
Joon
J
D050976:Basic-Leucine Zipper Transcription Factors; D002352:Carrier Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D017353:Gene Deletion; D025821:Polyubiquitin / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D011956:Receptors, Cell Surface / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D013816:Thermodynamics; D014157:Transcription Factors / Q000378:metabolism*; D054875:Ubiquitination; D014452:Ubiquitins / Q000378:metabolism
D050976:Basic-Leucine Zipper Transcription Factors; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C100415:DSK2 protein, S cerevisiae; C501391:GCN4 protein, S cerevisiae; C490846:RAD23 protein, S cerevisiae; C122019:RPN10 protein, S cerevisiae; D011956:Receptors, Cell Surface; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D014452:Ubiquitins; D025821:Polyubiquitin; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease