Cargando…

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...

Descripción completa

Detalles Bibliográficos
Autores principales: Matsumura, Yoshihiro, David, Larry L., Skach, William R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2011
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
_version_ 1782210045860118528
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
work_keys_str_mv AT matsumurayoshihiro roleofhsc70bindingcycleincftrfoldingandendoplasmicreticulumassociateddegradation
AT davidlarryl roleofhsc70bindingcycleincftrfoldingandendoplasmicreticulumassociateddegradation
AT skachwilliamr roleofhsc70bindingcycleincftrfoldingandendoplasmicreticulumassociateddegradation