Autoubiquitination of the Hrd1 Ligase Triggers Protein Retrotranslocation in ERAD.
Cell
; 166(2): 394-407, 2016 Jul 14.
Article
em En
| MEDLINE
| ID: mdl-27321670
ABSTRACT
Misfolded proteins of the ER are retrotranslocated to the cytosol, where they are polyubiquitinated, extracted from the membrane, and degraded by the proteasome. To investigate how the ER-associated Degradation (ERAD) machinery can accomplish retrotranslocation of a misfolded luminal protein domain across a lipid bilayer, we have reconstituted retrotranslocation with purified S. cerevisiae proteins, using proteoliposomes containing the multi-spanning ubiquitin ligase Hrd1. Retrotranslocation of the luminal domain of a membrane-spanning substrate is triggered by autoubiquitination of Hrd1. Substrate ubiquitination is a subsequent event, and the Cdc48 ATPase that completes substrate extraction from the membrane is not required for retrotranslocation. Ubiquitination of lysines in Hrd1's RING-finger domain is required for substrate retrotranslocation in vitro and for ERAD in vivo. Our results suggest that Hrd1 forms a ubiquitin-gated protein-conducting channel.
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Base de dados:
MEDLINE
Assunto principal:
Saccharomyces cerevisiae
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Dobramento de Proteína
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Proteínas de Saccharomyces cerevisiae
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Ubiquitina-Proteína Ligases
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Degradação Associada com o Retículo Endoplasmático
Idioma:
En
Revista:
Cell
Ano de publicação:
2016
Tipo de documento:
Article