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Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae
Both the yeast nascent polypeptide-associated complex (NAC) and the Hsp40/70-based chaperone system RAC-Ssb are systems tethered to the ribosome to assist cotranslational processes such as folding of nascent polypeptides. While loss of NAC does not cause phenotypic changes in yeast, the simultaneous...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Public Library of Science
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664479/ https://www.ncbi.nlm.nih.gov/pubmed/26618777 http://dx.doi.org/10.1371/journal.pone.0143457 |
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author | Ott, Ann-Kathrin Locher, Lisa Koch, Miriam Deuerling, Elke |
author_facet | Ott, Ann-Kathrin Locher, Lisa Koch, Miriam Deuerling, Elke |
author_sort | Ott, Ann-Kathrin |
collection | PubMed |
description | Both the yeast nascent polypeptide-associated complex (NAC) and the Hsp40/70-based chaperone system RAC-Ssb are systems tethered to the ribosome to assist cotranslational processes such as folding of nascent polypeptides. While loss of NAC does not cause phenotypic changes in yeast, the simultaneous deletion of genes coding for NAC and the chaperone Ssb (nacΔssbΔ) leads to strongly aggravated defects compared to cells lacking only Ssb, including impaired growth on plates containing L-canavanine or hygromycin B, aggregation of newly synthesized proteins and a reduced translational activity due to ribosome biogenesis defects. In this study, we dissected the functional properties of the individual NAC-subunits (α-NAC, β-NAC and β’-NAC) and of different NAC heterodimers found in yeast (αβ-NAC and αβ’-NAC) by analyzing their capability to complement the pleiotropic phenotype of nacΔssbΔ cells. We show that the abundant heterodimer αβ-NAC but not its paralogue αβ’-NAC is able to suppress all phenotypic defects of nacΔssbΔ cells including global protein aggregation as well as translation and growth deficiencies. This suggests that αβ-NAC and αβ’-NAC are functionally distinct from each other. The function of αβ-NAC strictly depends on its ribosome association and on its high level of expression. Expression of individual β-NAC, β’-NAC or α-NAC subunits as well as αβ’-NAC ameliorated protein aggregation in nacΔssbΔ cells to different extents while only β-NAC was able to restore growth defects suggesting chaperoning activities for β-NAC sufficient to decrease the sensitivity of nacΔssbΔ cells against L-canavanine or hygromycin B. Interestingly, deletion of the ubiquitin-associated (UBA)-domain of the α-NAC subunit strongly enhanced the aggregation preventing activity of αβ-NAC pointing to a negative regulatory role of this domain for the NAC chaperone activity in vivo. |
format | Online Article Text |
id | pubmed-4664479 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-46644792015-12-10 Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae Ott, Ann-Kathrin Locher, Lisa Koch, Miriam Deuerling, Elke PLoS One Research Article Both the yeast nascent polypeptide-associated complex (NAC) and the Hsp40/70-based chaperone system RAC-Ssb are systems tethered to the ribosome to assist cotranslational processes such as folding of nascent polypeptides. While loss of NAC does not cause phenotypic changes in yeast, the simultaneous deletion of genes coding for NAC and the chaperone Ssb (nacΔssbΔ) leads to strongly aggravated defects compared to cells lacking only Ssb, including impaired growth on plates containing L-canavanine or hygromycin B, aggregation of newly synthesized proteins and a reduced translational activity due to ribosome biogenesis defects. In this study, we dissected the functional properties of the individual NAC-subunits (α-NAC, β-NAC and β’-NAC) and of different NAC heterodimers found in yeast (αβ-NAC and αβ’-NAC) by analyzing their capability to complement the pleiotropic phenotype of nacΔssbΔ cells. We show that the abundant heterodimer αβ-NAC but not its paralogue αβ’-NAC is able to suppress all phenotypic defects of nacΔssbΔ cells including global protein aggregation as well as translation and growth deficiencies. This suggests that αβ-NAC and αβ’-NAC are functionally distinct from each other. The function of αβ-NAC strictly depends on its ribosome association and on its high level of expression. Expression of individual β-NAC, β’-NAC or α-NAC subunits as well as αβ’-NAC ameliorated protein aggregation in nacΔssbΔ cells to different extents while only β-NAC was able to restore growth defects suggesting chaperoning activities for β-NAC sufficient to decrease the sensitivity of nacΔssbΔ cells against L-canavanine or hygromycin B. Interestingly, deletion of the ubiquitin-associated (UBA)-domain of the α-NAC subunit strongly enhanced the aggregation preventing activity of αβ-NAC pointing to a negative regulatory role of this domain for the NAC chaperone activity in vivo. Public Library of Science 2015-11-30 /pmc/articles/PMC4664479/ /pubmed/26618777 http://dx.doi.org/10.1371/journal.pone.0143457 Text en © 2015 Ott et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Ott, Ann-Kathrin Locher, Lisa Koch, Miriam Deuerling, Elke Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae |
title | Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae
|
title_full | Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae
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title_fullStr | Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae
|
title_full_unstemmed | Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae
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title_short | Functional Dissection of the Nascent Polypeptide-Associated Complex in Saccharomyces cerevisiae
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title_sort | functional dissection of the nascent polypeptide-associated complex in saccharomyces cerevisiae |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664479/ https://www.ncbi.nlm.nih.gov/pubmed/26618777 http://dx.doi.org/10.1371/journal.pone.0143457 |
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