Novel ubiquitin-dependent quality control in the endoplasmic reticulum

Proteins of the endomembrane system undergo assisted folding in the endoplasmic reticulum (ER), then quality-control and, if misfolded, ER-associated degradation (ERAD). Recent findings on the biogenesis of a type-I membrane protein (an LRP6 mutant) lead us to hypothesize the existence of a novel mechanism promoting folding of membrane proteins from the cytosolic side of the ER. The proposed folding mechanism involves cycles of chaperone binding through mono-ubiquitylation and de-ubiquitylation, followed eventually by poly-ubiquitylation and ERAD. This suggests a novel dual role for ubiquitylation in the ER - dependent on the type of ubiquitin chains involved - in folding and in degradation, and highlights the potential importance of de-ubiquitylating enzymes.


Published in:
Trends in cell biology, 19, 8, 357-63
Year:
2009
Publisher:
Elsevier
ISSN:
1879-3088
Keywords:
Laboratories:




 Record created 2010-07-29, last modified 2018-03-17


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