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Updated: Dec 13, 2025

Functional Characterization of RING-Type E3 Ubiquitin Ligases In Vitro and In Planta
Published on: December 5, 2019
Quality Control of ER Membrane Proteins by the RNF185/Membralin Ubiquitin Ligase Complex
Michael L van de Weijer1, Logesvaran Krshnan1, Sabrina Liberatori1
1Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK.
Researchers discovered a new pathway for degrading misfolded membrane proteins in the endoplasmic reticulum (ER). This ER-associated degradation (ERAD) branch involves a specific ER membrane complex, offering insights into protein quality control.
Area of Science:
- Cellular Biology
- Molecular Biology
- Biochemistry
Background:
- Endoplasmic reticulum-associated degradation (ERAD) removes misfolded proteins.
- ERAD pathways for luminal proteins are known, but membrane protein quality control is less understood.
Purpose of the Study:
- To investigate the degradation pathways of ER membrane proteins.
- To identify novel components involved in membrane protein ERAD.
Main Methods:
- CRISPR-Cas9 genome-wide library screen in mammalian cells.
- Biochemical assays and mass spectrometry.
- Analysis of short-lived ER membrane model proteins.
Main Results:
- Identified a novel ERAD branch specific for a subset of membrane proteins.
- Characterized an ER membrane complex including RNF185, TMUB1/2, and TMEM259/Membralin.
- Demonstrated cooperation of this complex with UBE3C and p97 ATPase for substrate degradation.
Conclusions:
- ERAD exhibits substrate specificity for membrane proteins.
- Multiple determinants likely regulate membrane protein selection in ERAD.
- Discovered a new mechanism for membrane protein quality control in the ER.
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