Regulation of the 26S proteasome complex during oxidative stress.
The proteasome plays a pivotal role in the cellular response to oxidative stress. Here, we used biochemical and mass spectrometric methods to investigate structural changes in the 26S proteasomes from yeast and mammalian cells exposed to hydrogen peroxide (H₂O₂). Oxidative stress induced the dissociation of the 20S core particle from the 19S regulatory particle of the 26S proteasome, which resulted in loss of the activities of the 26S proteasome and accumulation of ubiquitinated proteins. H₂O₂ triggered the increased association of the proteasome-interacting protein Ecm29 with the purified 19S particle. Deletion of ECM29 in yeast cells prevented the disassembly of the 26S proteasome in response to oxidative stress, and ecm29 mutants were more sensitive to H₂O₂ than were wild-type cells, suggesting that separation of the 19S and 20S particles is important for cellular recovery from oxidative stress. The increased amount of free 20S core particles was required to degrade oxidized proteins. The Ecm29-dependent dissociation of the proteasome was independent of Yap1, a transcription factor that is critical for the oxidative stress response in yeast, and thus functions as a parallel defense pathway against H₂O₂-induced stress.
Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.
Xiaorong
X
Wang
James
J
Yen
Peter
P
Kaiser
Lan
L
Huang
D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D013058:Mass Spectrometry; D009154:Mutation; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
C551357:Ecm29 protein, S cerevisiae; D016877:Oxidants; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; C086677:YAP1 protein, S cerevisiae; D006861:Hydrogen Peroxide; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease