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Protein Phosphatase-1 Regulates Expression of Neuregulin-1
Protein phosphatase 1 (PP1), a cellular serine/threonine phosphatase, is targeted to cellular promoters by its major regulatory subunits, PP1 nuclear targeting subunit, nuclear inhibitor of PP1 (NIPP1) and RepoMan. PP1 is also targeted to RNA polymerase II (RNAPII) by NIPP1 where it can dephosphoryl...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192429/ https://www.ncbi.nlm.nih.gov/pubmed/27918433 http://dx.doi.org/10.3390/biology5040049 |
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author | Ammosova, Tatiana Washington, Kareem Rotimi, Jamie Kumari, Namita Smith, Kahli A. Niu, Xiaomei Jerebtsova, Marina Nekhai, Sergei |
author_facet | Ammosova, Tatiana Washington, Kareem Rotimi, Jamie Kumari, Namita Smith, Kahli A. Niu, Xiaomei Jerebtsova, Marina Nekhai, Sergei |
author_sort | Ammosova, Tatiana |
collection | PubMed |
description | Protein phosphatase 1 (PP1), a cellular serine/threonine phosphatase, is targeted to cellular promoters by its major regulatory subunits, PP1 nuclear targeting subunit, nuclear inhibitor of PP1 (NIPP1) and RepoMan. PP1 is also targeted to RNA polymerase II (RNAPII) by NIPP1 where it can dephosphorylate RNAPII and cycle-dependent kinase 9 (CDK9). Here, we show that treatment of cells with a small molecule activator of PP1 increases the abundance of a neuregulin-1 (NRG-1)-derived peptide. NRG-1 mRNA and protein levels were increased in the cells stably or transiently expressing mutant NIPP1 (mNIPP1) that does not bind PP1, but not in the cells expressing NIPP1. Expression of mNIPP1 also activated the NRG-1 promoter in an NF-κB-dependent manner. Analysis of extracts from mNIPP1 expressing cells by glycerol gradient centrifugation showed a redistribution of PP1 and CDK9 between large and small molecular weight complexes, and increased CDK9 Thr-186 phosphorylation. This correlated with the increased CDK9 activity. Further, RNAPII co-precipitated with mNIPP1, and phosphorylation of RNAPII C-terminal domain (CTD) Ser-2 residues was greater in cells expressing mNIPP1. In mNIPP1 expressing cells, okadaic acid, a cell-permeable inhibitor of PP1, did not increase Ser-2 CTD phosphorylation inhibited by flavopiridol, in contrast to the NIPP1 expressing cells, suggesting that PP1 was no longer involved in RNAPII dephosphorylation. Finally, media conditioned with mNIPP1 cells induced the proliferation of wild type 84-31 cells, consistent with a role of neuregulin-1 as a growth promoting factor. Our study indicates that deregulation of PP1/NIPP1 holoenzyme activates NRG-1 expression through RNAPII and CDK9 phosphorylation in a NF-κB dependent manner. |
format | Online Article Text |
id | pubmed-5192429 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-51924292017-01-03 Protein Phosphatase-1 Regulates Expression of Neuregulin-1 Ammosova, Tatiana Washington, Kareem Rotimi, Jamie Kumari, Namita Smith, Kahli A. Niu, Xiaomei Jerebtsova, Marina Nekhai, Sergei Biology (Basel) Article Protein phosphatase 1 (PP1), a cellular serine/threonine phosphatase, is targeted to cellular promoters by its major regulatory subunits, PP1 nuclear targeting subunit, nuclear inhibitor of PP1 (NIPP1) and RepoMan. PP1 is also targeted to RNA polymerase II (RNAPII) by NIPP1 where it can dephosphorylate RNAPII and cycle-dependent kinase 9 (CDK9). Here, we show that treatment of cells with a small molecule activator of PP1 increases the abundance of a neuregulin-1 (NRG-1)-derived peptide. NRG-1 mRNA and protein levels were increased in the cells stably or transiently expressing mutant NIPP1 (mNIPP1) that does not bind PP1, but not in the cells expressing NIPP1. Expression of mNIPP1 also activated the NRG-1 promoter in an NF-κB-dependent manner. Analysis of extracts from mNIPP1 expressing cells by glycerol gradient centrifugation showed a redistribution of PP1 and CDK9 between large and small molecular weight complexes, and increased CDK9 Thr-186 phosphorylation. This correlated with the increased CDK9 activity. Further, RNAPII co-precipitated with mNIPP1, and phosphorylation of RNAPII C-terminal domain (CTD) Ser-2 residues was greater in cells expressing mNIPP1. In mNIPP1 expressing cells, okadaic acid, a cell-permeable inhibitor of PP1, did not increase Ser-2 CTD phosphorylation inhibited by flavopiridol, in contrast to the NIPP1 expressing cells, suggesting that PP1 was no longer involved in RNAPII dephosphorylation. Finally, media conditioned with mNIPP1 cells induced the proliferation of wild type 84-31 cells, consistent with a role of neuregulin-1 as a growth promoting factor. Our study indicates that deregulation of PP1/NIPP1 holoenzyme activates NRG-1 expression through RNAPII and CDK9 phosphorylation in a NF-κB dependent manner. MDPI 2016-12-02 /pmc/articles/PMC5192429/ /pubmed/27918433 http://dx.doi.org/10.3390/biology5040049 Text en © 2016 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Ammosova, Tatiana Washington, Kareem Rotimi, Jamie Kumari, Namita Smith, Kahli A. Niu, Xiaomei Jerebtsova, Marina Nekhai, Sergei Protein Phosphatase-1 Regulates Expression of Neuregulin-1 |
title | Protein Phosphatase-1 Regulates Expression of Neuregulin-1 |
title_full | Protein Phosphatase-1 Regulates Expression of Neuregulin-1 |
title_fullStr | Protein Phosphatase-1 Regulates Expression of Neuregulin-1 |
title_full_unstemmed | Protein Phosphatase-1 Regulates Expression of Neuregulin-1 |
title_short | Protein Phosphatase-1 Regulates Expression of Neuregulin-1 |
title_sort | protein phosphatase-1 regulates expression of neuregulin-1 |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5192429/ https://www.ncbi.nlm.nih.gov/pubmed/27918433 http://dx.doi.org/10.3390/biology5040049 |
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