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Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system

Ribosome assembly is an essential process that consumes prodigious quantities of cellular resources. Ribosomal proteins cannot be overproduced in Saccharomyces cerevisiae because the excess proteins are rapidly degraded. However, the responsible quality control (QC) mechanisms remain poorly characte...

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Autores principales: Sung, Min-Kyung, Reitsma, Justin M., Sweredoski, Michael J., Hess, Sonja, Deshaies, Raymond J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5007085/
https://www.ncbi.nlm.nih.gov/pubmed/27385339
http://dx.doi.org/10.1091/mbc.E16-05-0290
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author Sung, Min-Kyung
Reitsma, Justin M.
Sweredoski, Michael J.
Hess, Sonja
Deshaies, Raymond J.
author_facet Sung, Min-Kyung
Reitsma, Justin M.
Sweredoski, Michael J.
Hess, Sonja
Deshaies, Raymond J.
author_sort Sung, Min-Kyung
collection PubMed
description Ribosome assembly is an essential process that consumes prodigious quantities of cellular resources. Ribosomal proteins cannot be overproduced in Saccharomyces cerevisiae because the excess proteins are rapidly degraded. However, the responsible quality control (QC) mechanisms remain poorly characterized. Here we demonstrate that overexpression of multiple proteins of the small and large yeast ribosomal subunits is suppressed. Rpl26 overexpressed from a plasmid can be detected in the nucleolus and nucleoplasm, but it largely fails to assemble into ribosomes and is rapidly degraded. However, if the endogenous RPL26 loci are deleted, plasmid-encoded Rpl26 assembles into ribosomes and localizes to the cytosol. Chemical and genetic perturbation studies indicate that overexpressed ribosomal proteins are degraded by the ubiquitin–proteasome system and not by autophagy. Inhibition of the proteasome led to accumulation of multiple endogenous ribosomal proteins in insoluble aggregates, consistent with the operation of this QC mechanism in the absence of ribosomal protein overexpression. Our studies reveal that ribosomal proteins that fail to assemble into ribosomes are rapidly distinguished from their assembled counterparts and ubiquitinated and degraded within the nuclear compartment.
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spelling pubmed-50070852016-11-16 Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system Sung, Min-Kyung Reitsma, Justin M. Sweredoski, Michael J. Hess, Sonja Deshaies, Raymond J. Mol Biol Cell Articles Ribosome assembly is an essential process that consumes prodigious quantities of cellular resources. Ribosomal proteins cannot be overproduced in Saccharomyces cerevisiae because the excess proteins are rapidly degraded. However, the responsible quality control (QC) mechanisms remain poorly characterized. Here we demonstrate that overexpression of multiple proteins of the small and large yeast ribosomal subunits is suppressed. Rpl26 overexpressed from a plasmid can be detected in the nucleolus and nucleoplasm, but it largely fails to assemble into ribosomes and is rapidly degraded. However, if the endogenous RPL26 loci are deleted, plasmid-encoded Rpl26 assembles into ribosomes and localizes to the cytosol. Chemical and genetic perturbation studies indicate that overexpressed ribosomal proteins are degraded by the ubiquitin–proteasome system and not by autophagy. Inhibition of the proteasome led to accumulation of multiple endogenous ribosomal proteins in insoluble aggregates, consistent with the operation of this QC mechanism in the absence of ribosomal protein overexpression. Our studies reveal that ribosomal proteins that fail to assemble into ribosomes are rapidly distinguished from their assembled counterparts and ubiquitinated and degraded within the nuclear compartment. The American Society for Cell Biology 2016-09-01 /pmc/articles/PMC5007085/ /pubmed/27385339 http://dx.doi.org/10.1091/mbc.E16-05-0290 Text en © 2016 Sung 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 for Cell Biology.
spellingShingle Articles
Sung, Min-Kyung
Reitsma, Justin M.
Sweredoski, Michael J.
Hess, Sonja
Deshaies, Raymond J.
Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system
title Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system
title_full Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system
title_fullStr Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system
title_full_unstemmed Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system
title_short Ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system
title_sort ribosomal proteins produced in excess are degraded by the ubiquitin–proteasome system
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5007085/
https://www.ncbi.nlm.nih.gov/pubmed/27385339
http://dx.doi.org/10.1091/mbc.E16-05-0290
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