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The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins

Flaviviruses translate their genomes as multi-pass transmembrane proteins at the endoplasmic reticulum (ER) membrane. Here, we show that the ER membrane protein complex (EMC) is indispensable for the expression of viral polyproteins. We demonstrated that EMC was essential for accurate folding and po...

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Detalles Bibliográficos
Autores principales: Ngo, Ashley M, Shurtleff, Matthew J, Popova, Katerina D, Kulsuptrakul, Jessie, Weissman, Jonathan S, Puschnik, Andreas S
Formato: Online Artículo Texto
Lenguaje:English
Publicado: eLife Sciences Publications, Ltd 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756788/
https://www.ncbi.nlm.nih.gov/pubmed/31516121
http://dx.doi.org/10.7554/eLife.48469
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author Ngo, Ashley M
Shurtleff, Matthew J
Popova, Katerina D
Kulsuptrakul, Jessie
Weissman, Jonathan S
Puschnik, Andreas S
author_facet Ngo, Ashley M
Shurtleff, Matthew J
Popova, Katerina D
Kulsuptrakul, Jessie
Weissman, Jonathan S
Puschnik, Andreas S
author_sort Ngo, Ashley M
collection PubMed
description Flaviviruses translate their genomes as multi-pass transmembrane proteins at the endoplasmic reticulum (ER) membrane. Here, we show that the ER membrane protein complex (EMC) is indispensable for the expression of viral polyproteins. We demonstrated that EMC was essential for accurate folding and post-translational stability rather than translation efficiency. Specifically, we revealed degradation of NS4A-NS4B, a region rich in transmembrane domains, in absence of EMC. Orthogonally, by serial passaging of virus on EMC-deficient cells, we identified two non-synonymous point mutations in NS4A and NS4B, which rescued viral replication. Finally, we showed a physical interaction between EMC and viral NS4B and that the NS4A-4B region adopts an aberrant topology in the absence of the EMC leading to degradation. Together, our data highlight how flaviviruses hijack the EMC for transmembrane protein biogenesis to achieve optimal expression of their polyproteins, which reinforces a role for the EMC in stabilizing challenging transmembrane proteins during synthesis.
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spelling pubmed-67567882019-09-25 The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins Ngo, Ashley M Shurtleff, Matthew J Popova, Katerina D Kulsuptrakul, Jessie Weissman, Jonathan S Puschnik, Andreas S eLife Microbiology and Infectious Disease Flaviviruses translate their genomes as multi-pass transmembrane proteins at the endoplasmic reticulum (ER) membrane. Here, we show that the ER membrane protein complex (EMC) is indispensable for the expression of viral polyproteins. We demonstrated that EMC was essential for accurate folding and post-translational stability rather than translation efficiency. Specifically, we revealed degradation of NS4A-NS4B, a region rich in transmembrane domains, in absence of EMC. Orthogonally, by serial passaging of virus on EMC-deficient cells, we identified two non-synonymous point mutations in NS4A and NS4B, which rescued viral replication. Finally, we showed a physical interaction between EMC and viral NS4B and that the NS4A-4B region adopts an aberrant topology in the absence of the EMC leading to degradation. Together, our data highlight how flaviviruses hijack the EMC for transmembrane protein biogenesis to achieve optimal expression of their polyproteins, which reinforces a role for the EMC in stabilizing challenging transmembrane proteins during synthesis. eLife Sciences Publications, Ltd 2019-09-13 /pmc/articles/PMC6756788/ /pubmed/31516121 http://dx.doi.org/10.7554/eLife.48469 Text en © 2019, Ngo et al http://creativecommons.org/licenses/by/4.0/ http://creativecommons.org/licenses/by/4.0/This article is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use and redistribution provided that the original author and source are credited.
spellingShingle Microbiology and Infectious Disease
Ngo, Ashley M
Shurtleff, Matthew J
Popova, Katerina D
Kulsuptrakul, Jessie
Weissman, Jonathan S
Puschnik, Andreas S
The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
title The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
title_full The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
title_fullStr The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
title_full_unstemmed The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
title_short The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
title_sort er membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
topic Microbiology and Infectious Disease
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6756788/
https://www.ncbi.nlm.nih.gov/pubmed/31516121
http://dx.doi.org/10.7554/eLife.48469
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