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Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation
The Hsp/c70 cytosolic chaperone system facilitates competing pathways of protein folding and degradation. Here we use a reconstituted cell-free system to investigate the mechanism and extent to which Hsc70 contributes to these co- and posttranslational decisions for the membrane protein cystic fibro...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The American Society for Cell Biology
2011
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3154877/ https://www.ncbi.nlm.nih.gov/pubmed/21697503 http://dx.doi.org/10.1091/mbc.E11-02-0137 |
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author | Matsumura, Yoshihiro David, Larry L. Skach, William R. |
author_facet | Matsumura, Yoshihiro David, Larry L. Skach, William R. |
author_sort | Matsumura, Yoshihiro |
collection | PubMed |
description | The Hsp/c70 cytosolic chaperone system facilitates competing pathways of protein folding and degradation. Here we use a reconstituted cell-free system to investigate the mechanism and extent to which Hsc70 contributes to these co- and posttranslational decisions for the membrane protein cystic fibrosis transmembrane conductance regulator (CFTR). Hsc70 binding to CFTR was destabilized by the C-terminal domain of Bag-1 (CBag), which stimulates client release by accelerating ADP-ATP exchange. Addition of CBag during CFTR translation slightly increased susceptibility of the newly synthesized protein to degradation, consistent with a profolding function for Hsc70. In contrast, posttranslational destabilization of Hsc70 binding nearly completely blocked CFTR ubiquitination, dislocation from the endoplasmic reticulum, and proteasome-mediated cleavage. This effect required molar excess of CBag relative to Hsc70 and was completely reversed by the CBag-binding subdomain of Hsc70. These results demonstrate that the profolding role of Hsc70 during cotranslational CFTR folding is counterbalanced by a dominant and essential role in posttranslational targeting to the ubiquitin-proteasome system. Moreover, the degradative outcome of Hsc70 binding appears highly sensitive to the duration of its binding cycle, which is in turn governed by the integrated expression of regulatory cochaperones. |
format | Online Article Text |
id | pubmed-3154877 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2011 |
publisher | The American Society for Cell Biology |
record_format | MEDLINE/PubMed |
spelling | pubmed-31548772011-10-30 Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation Matsumura, Yoshihiro David, Larry L. Skach, William R. Mol Biol Cell Articles The Hsp/c70 cytosolic chaperone system facilitates competing pathways of protein folding and degradation. Here we use a reconstituted cell-free system to investigate the mechanism and extent to which Hsc70 contributes to these co- and posttranslational decisions for the membrane protein cystic fibrosis transmembrane conductance regulator (CFTR). Hsc70 binding to CFTR was destabilized by the C-terminal domain of Bag-1 (CBag), which stimulates client release by accelerating ADP-ATP exchange. Addition of CBag during CFTR translation slightly increased susceptibility of the newly synthesized protein to degradation, consistent with a profolding function for Hsc70. In contrast, posttranslational destabilization of Hsc70 binding nearly completely blocked CFTR ubiquitination, dislocation from the endoplasmic reticulum, and proteasome-mediated cleavage. This effect required molar excess of CBag relative to Hsc70 and was completely reversed by the CBag-binding subdomain of Hsc70. These results demonstrate that the profolding role of Hsc70 during cotranslational CFTR folding is counterbalanced by a dominant and essential role in posttranslational targeting to the ubiquitin-proteasome system. Moreover, the degradative outcome of Hsc70 binding appears highly sensitive to the duration of its binding cycle, which is in turn governed by the integrated expression of regulatory cochaperones. The American Society for Cell Biology 2011-08-15 /pmc/articles/PMC3154877/ /pubmed/21697503 http://dx.doi.org/10.1091/mbc.E11-02-0137 Text en © 2011 Matsumura et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0). “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society of Cell Biology. |
spellingShingle | Articles Matsumura, Yoshihiro David, Larry L. Skach, William R. Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation |
title | Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation |
title_full | Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation |
title_fullStr | Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation |
title_full_unstemmed | Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation |
title_short | Role of Hsc70 binding cycle in CFTR folding and endoplasmic reticulum–associated degradation |
title_sort | role of hsc70 binding cycle in cftr folding and endoplasmic reticulum–associated degradation |
topic | Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3154877/ https://www.ncbi.nlm.nih.gov/pubmed/21697503 http://dx.doi.org/10.1091/mbc.E11-02-0137 |
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