Cargando…

N-Alpha-Acetyltransferases and Regulation of CFTR Expression

The majority of cystic fibrosis (CF)-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) lead to the misfolding, mistrafficking, and degradation of the mutant protein. Inhibition of degradation does not effectively increase the amount of trafficking competent CFTR, bu...

Descripción completa

Detalles Bibliográficos
Autores principales: Vetter, Ali J., Karamyshev, Andrey L., Patrick, Anna E., Hudson, Henry, Thomas, Philip J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868295/
https://www.ncbi.nlm.nih.gov/pubmed/27182737
http://dx.doi.org/10.1371/journal.pone.0155430
_version_ 1782432163143090176
author Vetter, Ali J.
Karamyshev, Andrey L.
Patrick, Anna E.
Hudson, Henry
Thomas, Philip J.
author_facet Vetter, Ali J.
Karamyshev, Andrey L.
Patrick, Anna E.
Hudson, Henry
Thomas, Philip J.
author_sort Vetter, Ali J.
collection PubMed
description The majority of cystic fibrosis (CF)-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) lead to the misfolding, mistrafficking, and degradation of the mutant protein. Inhibition of degradation does not effectively increase the amount of trafficking competent CFTR, but typically leads to increased ER retention of misfolded forms. Thus, the initial off pathway steps occur early in the processing of the protein. To identify proteins that interact with these early forms of CFTR, in vitro crosslink experiments identified cotranslational partners of the nascent chain of the severe misfolded mutant, G85E CFTR. The mutant preferentially interacts with a subunit of an N-alpha-acetyltransferase A. Based on recent reports that acetylation of the N-termini of some N-end rule substrates control their ubiquitination and subsequent degradation, a potential role for this modification in regulation of CFTR expression was assessed. Knockdown experiments identified two complexes, which affect G85E CFTR proteins levels, NatA and NatB. Effects of the knockdowns on mRNA levels, translation rates, and degradation rates established that the two complexes regulate G85E CFTR through two separate mechanisms. NatA acts indirectly by regulating transcription levels and NatB acts through a previously identified, but incompletely understood posttranslational mechanism. This regulation did not effect trafficking of G85E CFTR, which remains retained in the ER, nor did it alter the degradation rate of CFTR. A mutation predicted to inhibit N-terminal acetylation of CFTR, Q2P, was without effect, suggesting neither system acts directly on CFTR. These results contradict the prediction that N-terminal acetylation of CFTR determines its fitness as a proteasome substrate, but rather NatB plays a role in the conformational maturation of CFTR in the ER through actions on an unidentified protein.
format Online
Article
Text
id pubmed-4868295
institution National Center for Biotechnology Information
language English
publishDate 2016
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-48682952016-05-26 N-Alpha-Acetyltransferases and Regulation of CFTR Expression Vetter, Ali J. Karamyshev, Andrey L. Patrick, Anna E. Hudson, Henry Thomas, Philip J. PLoS One Research Article The majority of cystic fibrosis (CF)-causing mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) lead to the misfolding, mistrafficking, and degradation of the mutant protein. Inhibition of degradation does not effectively increase the amount of trafficking competent CFTR, but typically leads to increased ER retention of misfolded forms. Thus, the initial off pathway steps occur early in the processing of the protein. To identify proteins that interact with these early forms of CFTR, in vitro crosslink experiments identified cotranslational partners of the nascent chain of the severe misfolded mutant, G85E CFTR. The mutant preferentially interacts with a subunit of an N-alpha-acetyltransferase A. Based on recent reports that acetylation of the N-termini of some N-end rule substrates control their ubiquitination and subsequent degradation, a potential role for this modification in regulation of CFTR expression was assessed. Knockdown experiments identified two complexes, which affect G85E CFTR proteins levels, NatA and NatB. Effects of the knockdowns on mRNA levels, translation rates, and degradation rates established that the two complexes regulate G85E CFTR through two separate mechanisms. NatA acts indirectly by regulating transcription levels and NatB acts through a previously identified, but incompletely understood posttranslational mechanism. This regulation did not effect trafficking of G85E CFTR, which remains retained in the ER, nor did it alter the degradation rate of CFTR. A mutation predicted to inhibit N-terminal acetylation of CFTR, Q2P, was without effect, suggesting neither system acts directly on CFTR. These results contradict the prediction that N-terminal acetylation of CFTR determines its fitness as a proteasome substrate, but rather NatB plays a role in the conformational maturation of CFTR in the ER through actions on an unidentified protein. Public Library of Science 2016-05-16 /pmc/articles/PMC4868295/ /pubmed/27182737 http://dx.doi.org/10.1371/journal.pone.0155430 Text en © 2016 Vetter 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 (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Vetter, Ali J.
Karamyshev, Andrey L.
Patrick, Anna E.
Hudson, Henry
Thomas, Philip J.
N-Alpha-Acetyltransferases and Regulation of CFTR Expression
title N-Alpha-Acetyltransferases and Regulation of CFTR Expression
title_full N-Alpha-Acetyltransferases and Regulation of CFTR Expression
title_fullStr N-Alpha-Acetyltransferases and Regulation of CFTR Expression
title_full_unstemmed N-Alpha-Acetyltransferases and Regulation of CFTR Expression
title_short N-Alpha-Acetyltransferases and Regulation of CFTR Expression
title_sort n-alpha-acetyltransferases and regulation of cftr expression
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4868295/
https://www.ncbi.nlm.nih.gov/pubmed/27182737
http://dx.doi.org/10.1371/journal.pone.0155430
work_keys_str_mv AT vetteralij nalphaacetyltransferasesandregulationofcftrexpression
AT karamyshevandreyl nalphaacetyltransferasesandregulationofcftrexpression
AT patrickannae nalphaacetyltransferasesandregulationofcftrexpression
AT hudsonhenry nalphaacetyltransferasesandregulationofcftrexpression
AT thomasphilipj nalphaacetyltransferasesandregulationofcftrexpression