A Hydrophobic Target: Using the Paramyxovirus Fusion Protein Transmembrane Domain To Modulate Fusion Protein Stability.

Abstract

Enveloped viruses utilize surface glycoproteins to bind and fuse with a target cell membrane. The zoonotic Hendra virus (HeV), a member of the family Paramyxoviridae, utilizes the attachment protein (G) and the fusion protein (F) to perform these critical functions. Upon triggering, the trimeric F protein undergoes a large, irreversible conformation change to drive membrane fusion. Previously, we have shown that the transmembrane (TM) domain of the F protein, separate from the rest of the protein, is present in a monomer-trimer equilibrium. This TM-TM association contributes to the stability of the prefusion form of the protein, supporting a role for TM-TM interactions in the control of F protein conformational changes. To determine the impact of disrupting TM-TM interactions, constructs expressing the HeV F TM with limited flanking sequences were synthesized. Coexpression of these constructs with HeV F resulted in dramatic reductions in the stability of F protein expression and fusion activity. In contrast, no effects were observed when the HeV F TM constructs were coexpressed with the nonhomologous parainfluenza virus 5 (PIV5) fusion protein, indicating a requirement for specific interactions. To further examine this, a TM peptide homologous to the PIV5 F TM domain was synthesized. Addition of the peptide prior to infection inhibited infection with PIV5 but did not significantly affect infection with human metapneumovirus, a related virus. These results indicate that targeted disruption of TM-TM interactions significantly impact viral fusion protein stability and function, presenting these interactions as a novel target for antiviral development.IMPORTANCE Enveloped viruses require virus-cell membrane fusion to release the viral genome and replicate. The viral fusion protein triggers from the pre- to the postfusion conformation, an essentially irreversible change, to drive membrane fusion. We found that small proteins containing the TM and a limited flanking region homologous to the fusion protein of the zoonotic Hendra virus reduced protein expression and fusion activity. The introduction of exogenous TM peptides may displace a TM domain, disrupting native TM-TM interactions and globally destabilizing the fusion protein. Supporting this hypothesis, we showed that a sequence-specific transmembrane peptide dramatically reduced viral infection in another enveloped virus model, suggesting a broader inhibitory mechanism. Viral fusion protein TM-TM interactions are important for protein function, and disruption of these interactions dramatically reduces protein stability.

• Authors: Chelsea T Barrett, Stacy R Webb, Rebecca Ellis Dutch
• Journal: Journal of virology (J Virol) Vol. 93 Issue 17 (09 01 2019) ISSN: 1098-5514 [Electronic] United States
• PMID: 31217248 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2019 American Society for Microbiology.

Chemical References

• Peptides
• Viral Fusion Proteins

Topics

• Animals
• Binding Sites (drug effects)
• Chlorocebus aethiops
• Hendra Virus (chemistry, genetics, metabolism)
• Hydrophobic and Hydrophilic Interactions (drug effects)
• Parainfluenza Virus 5 (chemistry, genetics, metabolism)
• Paramyxovirinae (chemistry, genetics, metabolism)
• Peptides (pharmacology)
• Protein Conformation (drug effects)
• Protein Domains (drug effects)
• Protein Stability
• Vero Cells
• Viral Fusion Proteins (chemistry, drug effects, genetics)