Please use this identifier to cite or link to this item: http://hdl.handle.net/2445/25203
Title: Dissociation from BiP and Retrotranslocation of Unassembled Immunoglobulin Light Chains Are Tightly Coupled to Proteasome Activity
Author: Chillarón Chaves, José Julio
Haas, Ingrid G.
Keywords: Proteïnes
Immunoglobulines
Proteins
Immunoglobulins
Issue Date: 4-Nov-2009
Publisher: American Society for Cell Biology
Abstract: Unassembled immunoglobulin light chains expressed by the mouse plasmacytoma cell line NS1 (KNS1) are degraded in vivo with a half-life of 50-60 min in a way that closely resembles endoplasmic reticulum (ER)-associated degradation (Knittler et al., 1995). Here we show that the peptide aldehydes MG132 and PS1 and the specific proteasome inhibitor lactacystin effectively increased the half-life of KNS1, arguing for a proteasome-mediated degradation pathway. Subcellular fractionation and protease protection assays have indicated an ER localization of KNS1 upon proteasome inhibition. This was independently confirmed by the analysis of the folding state of KNS1and size fractionation experiments showing that the immunoglobulin light chain remained bound to the ER chaperone BiP when the activity of the proteasome was blocked. Moreover, kinetic studies performed in lactacystin-treated cells revealed a time-dependent increase in the physical stability of the BiP-KNS1complex, suggesting that additional proteins are present in the older complex. Together, our data support a model for ER-associated degradation in which both the release of a soluble nonglycosylated protein from BiP and its retrotranslocation out of the ER are tightly coupled with proteasome activity.
Note: Reproducció del document publicat a: http://www.molbiolcell.org/content/11/1/217.abstract?sid=e894be54-92b5-466b-b357-88c7850e26eb
It is part of: Molecular Biology of the Cell, 2009, vol. 11, núm. 1, p. 217-226
URI: http://hdl.handle.net/2445/25203
ISSN: 1059-1524
Appears in Collections:Articles publicats en revistes (Biologia Cel·lular, Fisiologia i Immunologia)

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