Homology-guided identification of a conserved motif linking the antiviral functions of IFITM3 to its oligomeric state
- National Cancer Institute, United States
- King's College London, United Kingdom
Abstract
The interferon-inducible transmembrane (IFITM) proteins belong to the Dispanin/CD225 family and inhibit diverse virus infections. IFITM3 reduces membrane fusion between cells and virions through a poorly characterized mechanism. Mutation of proline rich transmembrane protein 2 (PRRT2), a regulator of neurotransmitter release, at glycine-305 was previously linked to paroxysmal neurological disorders in humans. Here, we show that glycine-305 and the homologous site in IFITM3, glycine-95, drive protein oligomerization from within a GxxxG motif. Mutation of glycine-95 (and to a lesser extent, glycine-91) disrupted IFITM3 oligomerization and reduced its antiviral activity against Influenza A virus. An oligomerization-defective variant was used to reveal that IFITM3 promotes membrane rigidity in a glycine-95-dependent and amphipathic helix-dependent manner. Furthermore, a compound which counteracts virus inhibition by IFITM3, amphotericin B, prevented the IFITM3-mediated rigidification of membranes. Overall, these data suggest that IFITM3 oligomers inhibit virus-cell fusion by promoting membrane rigidity.
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All data generated or analysed during this study are included in the manuscript and supporting files.
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Author details
Sergi Padilla-Parra
Funding
National Institutes of Health (Intramural Research Program)
- Kazi Rahman
- Charles A Coomer
- Saliha Majdoul
- Selena Y Ding
- Alex A Compton
European Research Council (ERC-2019-CoG-863869 FUSION)
- Sergi Padilla-Parra
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.
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Homology-guided identification of a conserved motif linking the antiviral functions of IFITM3 to its oligomeric state
eLife 9:e58537.
https://doi.org/10.7554/eLife.58537
