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Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32

BACKGROUND: The gap junction protein, Connexin32 (Cx32), is expressed in various tissues including liver, exocrine pancreas, gastrointestinal epithelium, and the glia of the central and peripheral nervous system. Gap junction-mediated cell-cell communication and channel-independent processes of Cx32...

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Autores principales: Alaei, Sarah R., Abrams, Charles K., Bulinski, J. Chloë, Hertzberg, Elliot L., Freidin, Mona M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: BioMed Central 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162937/
https://www.ncbi.nlm.nih.gov/pubmed/30268116
http://dx.doi.org/10.1186/s12860-018-0173-0
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author Alaei, Sarah R.
Abrams, Charles K.
Bulinski, J. Chloë
Hertzberg, Elliot L.
Freidin, Mona M.
author_facet Alaei, Sarah R.
Abrams, Charles K.
Bulinski, J. Chloë
Hertzberg, Elliot L.
Freidin, Mona M.
author_sort Alaei, Sarah R.
collection PubMed
description BACKGROUND: The gap junction protein, Connexin32 (Cx32), is expressed in various tissues including liver, exocrine pancreas, gastrointestinal epithelium, and the glia of the central and peripheral nervous system. Gap junction-mediated cell-cell communication and channel-independent processes of Cx32 contribute to the regulation of physiological and cellular activities such as glial differentiation, survival, and proliferation; maintenance of the hepatic epithelium; and axonal myelination. Mutations in Cx32 cause X-linked Charcot–Marie–Tooth disease (CMT1X), an inherited peripheral neuropathy. Several CMT1X causing mutations are found in the cytoplasmic domains of Cx32, a region implicated in the regulation of gap junction assembly, turnover and function. Here we investigate the roles of acetylation and ubiquitination in the C-terminus on Cx32 protein function. Cx32 protein turnover, ubiquitination, and response to deacetylase inhibitors were determined for wild-type and C-terminus lysine mutants using transiently transfected Neuro2A (N2a) cells. RESULTS: We report here that Cx32 is acetylated in transfected N2a cells and that inhibition of the histone deacetylase, HDAC6, results in an accumulation of Cx32. We identified five lysine acetylation targets in the C-terminus. Mutational analysis demonstrates that these lysines are involved in the regulation of Cx32 ubiquitination and turnover. While these lysines are not required for functional Cx32 mediated cell-cell communication, BrdU incorporation studies demonstrate that their relative acetylation state plays a channel-independent role in Cx32-mediated control of cell proliferation. CONCLUSION: Taken together these results highlight the role of post translational modifications and lysines in the C-terminal tail of Cx32 in the fine-tuning of Cx32 protein stability and channel-independent functions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12860-018-0173-0) contains supplementary material, which is available to authorized users.
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spelling pubmed-61629372018-10-04 Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32 Alaei, Sarah R. Abrams, Charles K. Bulinski, J. Chloë Hertzberg, Elliot L. Freidin, Mona M. BMC Cell Biol Research Article BACKGROUND: The gap junction protein, Connexin32 (Cx32), is expressed in various tissues including liver, exocrine pancreas, gastrointestinal epithelium, and the glia of the central and peripheral nervous system. Gap junction-mediated cell-cell communication and channel-independent processes of Cx32 contribute to the regulation of physiological and cellular activities such as glial differentiation, survival, and proliferation; maintenance of the hepatic epithelium; and axonal myelination. Mutations in Cx32 cause X-linked Charcot–Marie–Tooth disease (CMT1X), an inherited peripheral neuropathy. Several CMT1X causing mutations are found in the cytoplasmic domains of Cx32, a region implicated in the regulation of gap junction assembly, turnover and function. Here we investigate the roles of acetylation and ubiquitination in the C-terminus on Cx32 protein function. Cx32 protein turnover, ubiquitination, and response to deacetylase inhibitors were determined for wild-type and C-terminus lysine mutants using transiently transfected Neuro2A (N2a) cells. RESULTS: We report here that Cx32 is acetylated in transfected N2a cells and that inhibition of the histone deacetylase, HDAC6, results in an accumulation of Cx32. We identified five lysine acetylation targets in the C-terminus. Mutational analysis demonstrates that these lysines are involved in the regulation of Cx32 ubiquitination and turnover. While these lysines are not required for functional Cx32 mediated cell-cell communication, BrdU incorporation studies demonstrate that their relative acetylation state plays a channel-independent role in Cx32-mediated control of cell proliferation. CONCLUSION: Taken together these results highlight the role of post translational modifications and lysines in the C-terminal tail of Cx32 in the fine-tuning of Cx32 protein stability and channel-independent functions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12860-018-0173-0) contains supplementary material, which is available to authorized users. BioMed Central 2018-09-29 /pmc/articles/PMC6162937/ /pubmed/30268116 http://dx.doi.org/10.1186/s12860-018-0173-0 Text en © The Author(s). 2018 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.
spellingShingle Research Article
Alaei, Sarah R.
Abrams, Charles K.
Bulinski, J. Chloë
Hertzberg, Elliot L.
Freidin, Mona M.
Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32
title Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32
title_full Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32
title_fullStr Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32
title_full_unstemmed Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32
title_short Acetylation of C-terminal lysines modulates protein turnover and stability of Connexin-32
title_sort acetylation of c-terminal lysines modulates protein turnover and stability of connexin-32
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6162937/
https://www.ncbi.nlm.nih.gov/pubmed/30268116
http://dx.doi.org/10.1186/s12860-018-0173-0
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