ER-Golgi traffic is a prerequisite for efficient ER degradation

Taxis, C.; Vogel, F.; Wolf, D.H.

ER-Golgi traffic is a prerequisite for efficient ER degradation

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Item Type:	Article
Title:	ER-Golgi traffic is a prerequisite for efficient ER degradation
Creators Name:	Taxis, C., Vogel, F. and Wolf, D.H.
Abstract:	Protein quality control is an essential function of the endoplasmic reticulum. Misfolded proteins unable to acquire their native conformation are retained in the endoplasmic reticulum, retro-translocated back into the cytosol, and degraded via the ubiquitin-proteasome system. We show that efficient degradation of soluble malfolded proteins in yeast requires a fully competent early secretory pathway. Mutations in proteins essential for ER-Golgi protein traffic severely inhibit ER degradation of the model substrate CPY. We found ER localization of CPY in WT cells, but no other specific organelle for ER degradation could be identified by electron microscopy studies. Because CPY* is degraded in COPI coat mutants, only a minor fraction of CPY* or of a proteinaceous factor required for degradation seems to enter the recycling pathway between ER and Golgi. Therefore, we propose that the disorganized structure of the ER and/or the mislocalization of Kar2p, observed in early secretory mutants, is responsible for the reduction in CPY* degradation. Further, we observed that mutations in proteins directly involved in degradation of malfolded proteins (Der1p, Der3/Hrd1p, and Hrd3p) lead to morphological changes of the endoplasmic reticulum and the Golgi, escape of CPY* into the secretory pathway and a slower maturation rate of wild-type CPY.
Keywords:	Cycloheximide, Endoplasmic Reticulum, Genotype, Golgi Apparatus, Kinetics, Plasmids, Protein Folding, Saccharomyces Cerevisiae Proteins, Second Messenger Systems
Source:	Molecular Biology of the Cell
ISSN:	1059-1524
Publisher:	American Society for Cell Biology
Volume:	13
Number:	6
Page Range:	1806-1818
Date:	1 June 2002
Additional Information:	Copyright (c) 2002 by The American Society for Cell Biology
Official Publication:	https://doi.org/10.1091/mbc.01-08-0399
PubMed:	View item in PubMed

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