The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
- Chan Zuckerberg Biohub, United States
- University of California, San Francisco, United States
Abstract
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.
Data availability
Ribosome profiling/RNAseq data have been deposited as NCBI BioProject under the accession code PRJNA526529.
Article and author information
Author details
Matthew J Shurtleff
Jonathan S Weissman
Andreas S Puschnik
Funding
Howard Hughes Medical Institute
- Jonathan S Weissman
Helen Hay Whitney Foundation
- Matthew J Shurtleff
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Ngo et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 4,063
- views
-
- 652
- downloads
-
- 61
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Citations by DOI
-
- 61
- citations for umbrella DOI https://doi.org/10.7554/eLife.48469
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
The ER membrane protein complex is required to ensure correct topology and stable expression of flavivirus polyproteins
eLife 8:e48469.
https://doi.org/10.7554/eLife.48469
