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Updated: Jan 6, 2026
High-throughput Antiviral Assays to Screen for Inhibitors of Zika Virus Replication
Published on: October 30, 2021
Zika Virus NS3 Mimics a Cellular 14-3-3-Binding Motif to Antagonize RIG-I- and MDA5-Mediated Innate Immunity
William Riedl1, Dhiraj Acharya1, Jung-Hyun Lee1
1Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA.
Abstract:
14-3-3 protein family members facilitate the translocation of RIG-I-like receptors (RLRs) to organelles that mediate downstream RLR signaling, leading to interferon production. 14-3-3ϵ promotes the cytosolic-to-mitochondrial translocation of RIG-I, while 14-3-3η facilitates MDA5 translocation to mitochondria. We show that the NS3 protein of Zika virus (ZIKV) antagonizes antiviral gene induction by RIG-I and MDA5 by binding to and sequestering the scaffold proteins 14-3-3ϵ and 14-3-3η. 14-3-3-binding is mediated by a negatively charged RLDP motif in NS3 that is conserved in ZIKV strains of African and Asian lineages and is similar to the one found in dengue and West Nile viruses. ZIKV NS3 is sufficient to inhibit the RLR-14-3-3ϵ/η interaction and to suppress antiviral signaling. Mutational perturbation of 14-3-3ϵ/η binding in a recombinant ZIKV leads to enhanced innate immune responses and impaired growth kinetics. Our study provides molecular understanding of immune evasion functions of ZIKV, which may guide vaccine and anti-flaviviral therapy development.
Insights
Zika virus NS3 protein blocks antiviral signaling by binding 14-3-3 proteins, which are essential for RIG-I-like receptor function. Disrupting this interaction enhances immune responses and hinders viral growth, offering insights for therapies.
Area of Science:
- Immunology
- Virology
- Molecular Biology
Background:
- 14-3-3 proteins are crucial for RLR signaling, mediating interferon production.
- 14-3-3ϵ and 14-3-3η facilitate RIG-I and MDA5 translocation to mitochondria, respectively.
- Zika virus (ZIKV) evades host immunity through viral proteins like NS3.
Purpose of the Study:
- To investigate the mechanism by which ZIKV NS3 antagonizes RLR-mediated antiviral signaling.
- To elucidate the role of 14-3-3 proteins in ZIKV immune evasion.
Main Methods:
- Biochemical assays to study protein-protein interactions between ZIKV NS3 and 14-3-3 proteins.
- Site-directed mutagenesis to disrupt the 14-3-3 binding motif in ZIKV NS3.
- Analysis of antiviral gene induction and viral replication in cells and recombinant ZIKV models.
Main Results:
- ZIKV NS3 protein binds and sequesters 14-3-3ϵ and 14-3-3η, inhibiting RLR signaling.
- A conserved negatively charged RLDP motif in NS3 mediates 14-3-3 binding.
- Mutating the 14-3-3 binding site in ZIKV NS3 enhances innate immune responses and reduces viral growth.
Conclusions:
- ZIKV NS3 employs a conserved motif to antagonize host antiviral immunity by disrupting RLR-14-3-3 interactions.
- Understanding this immune evasion strategy provides a basis for developing ZIKV vaccines and antiviral therapies.
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