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Uncoupling retro‐translocation and degradation in the ER‐associated degradation of a soluble protein
Author(s) -
Lee Robert J,
Liu Changwei,
Harty Carol,
McCracken Ardythe A,
Latterich Martin,
Römisch Karin,
DeMartino George N,
Thomas Philip J,
Brodsky Jeffrey L
Publication year - 2004
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600232
Subject(s) - endoplasmic reticulum associated protein degradation , endoplasmic reticulum , proteasome , biology , cytoplasm , cytosol , protein degradation , chaperone (clinical) , microbiology and biotechnology , biochemistry , ubiquitin , yeast , unfolded protein response , enzyme , gene , medicine , pathology
Aberrant polypeptides in the endoplasmic reticulum (ER) are retro‐translocated to the cytoplasm and degraded by the 26S proteasome via ER‐associated degradation (ERAD). To begin to resolve the requirements for the retro‐translocation and degradation steps during ERAD, a cell‐free assay was used to investigate the contributions of specific factors in the yeast cytosol and in ER‐derived microsomes during the ERAD of a model, soluble polypeptide. As ERAD was unaffected when cytoplasmic chaperone activity was compromised, we asked whether proteasomes on their own supported both export and degradation in this system. Proficient ERAD was observed if wild‐type cytosol was substituted with either purified yeast or mammalian proteasomes. Moreover, addition of only the 19S cap of the proteasome catalyzed ATP‐dependent export of the polypeptide substrate, which was degraded upon subsequent addition of the 20S particle.