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Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae
The production of ribosomes and tRNAs for protein synthesis has a high energetic cost and is under tight transcriptional control to ensure that the level of RNA synthesis is balanced with nutrient availability and the prevailing environmental conditions. In the RNA polymerase (pol) III system in yea...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2015
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4430316/ https://www.ncbi.nlm.nih.gov/pubmed/25970584 http://dx.doi.org/10.1371/journal.pone.0127225 |
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author | Lee, Jaehoon Moir, Robyn D. Willis, Ian M. |
author_facet | Lee, Jaehoon Moir, Robyn D. Willis, Ian M. |
author_sort | Lee, Jaehoon |
collection | PubMed |
description | The production of ribosomes and tRNAs for protein synthesis has a high energetic cost and is under tight transcriptional control to ensure that the level of RNA synthesis is balanced with nutrient availability and the prevailing environmental conditions. In the RNA polymerase (pol) III system in yeast, nutrients and stress affect transcription through a bifurcated signaling pathway in which protein kinase A (PKA) and TORC1 activity directly or indirectly, through downstream kinases, alter the phosphorylation state and function of the Maf1 repressor and Rpc53, a TFIIF-like subunit of the polymerase. However, numerous lines of evidence suggest greater complexity in the regulatory network including the phosphoregulation of other pol III components. To address this issue, we systematically examined all 17 subunits of pol III along with the three subunits of the initiation factor TFIIIB for evidence of differential phosphorylation in response to inhibition of TORC1. A relatively high stoichiometry of phosphorylation was observed for several of these proteins and the Rpc82 subunit of the polymerase and the Bdp1 subunit of TFIIIB were found to be differentially phosphorylated. Bdp1 is phosphorylated on four major sites during exponential growth and the protein is variably dephosphorylated under conditions that inhibit tRNA gene transcription. PKA, the TORC1-regulated kinase Sch9 and protein kinase CK2 are all implicated in the phosphorylation of Bdp1. Alanine substitutions at the four phosphosites cause hyper-repression of transcription indicating that phosphorylation of Bdp1 opposes Maf1-mediated repression. The new findings suggest an integrated regulatory model for signaling events controlling pol III transcription. |
format | Online Article Text |
id | pubmed-4430316 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2015 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-44303162015-05-21 Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae Lee, Jaehoon Moir, Robyn D. Willis, Ian M. PLoS One Research Article The production of ribosomes and tRNAs for protein synthesis has a high energetic cost and is under tight transcriptional control to ensure that the level of RNA synthesis is balanced with nutrient availability and the prevailing environmental conditions. In the RNA polymerase (pol) III system in yeast, nutrients and stress affect transcription through a bifurcated signaling pathway in which protein kinase A (PKA) and TORC1 activity directly or indirectly, through downstream kinases, alter the phosphorylation state and function of the Maf1 repressor and Rpc53, a TFIIF-like subunit of the polymerase. However, numerous lines of evidence suggest greater complexity in the regulatory network including the phosphoregulation of other pol III components. To address this issue, we systematically examined all 17 subunits of pol III along with the three subunits of the initiation factor TFIIIB for evidence of differential phosphorylation in response to inhibition of TORC1. A relatively high stoichiometry of phosphorylation was observed for several of these proteins and the Rpc82 subunit of the polymerase and the Bdp1 subunit of TFIIIB were found to be differentially phosphorylated. Bdp1 is phosphorylated on four major sites during exponential growth and the protein is variably dephosphorylated under conditions that inhibit tRNA gene transcription. PKA, the TORC1-regulated kinase Sch9 and protein kinase CK2 are all implicated in the phosphorylation of Bdp1. Alanine substitutions at the four phosphosites cause hyper-repression of transcription indicating that phosphorylation of Bdp1 opposes Maf1-mediated repression. The new findings suggest an integrated regulatory model for signaling events controlling pol III transcription. Public Library of Science 2015-05-13 /pmc/articles/PMC4430316/ /pubmed/25970584 http://dx.doi.org/10.1371/journal.pone.0127225 Text en © 2015 Lee 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 Lee, Jaehoon Moir, Robyn D. Willis, Ian M. Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae |
title | Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae
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title_full | Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae
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title_fullStr | Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae
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title_full_unstemmed | Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae
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title_short | Differential Phosphorylation of RNA Polymerase III and the Initiation Factor TFIIIB in Saccharomyces cerevisiae
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title_sort | differential phosphorylation of rna polymerase iii and the initiation factor tfiiib in saccharomyces cerevisiae |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4430316/ https://www.ncbi.nlm.nih.gov/pubmed/25970584 http://dx.doi.org/10.1371/journal.pone.0127225 |
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