Biology subjects

Moayyed, A.

Publications and source records attributed to Moayyed, A..

2 recordsLinked to original sources

bioRxiv2026

Antagonism of stress granules key for SARS-CoV-2 infection and pathogenesis.

Viruses must subvert host responses to facilitate successful infection. While most antiviral responses are associated with interferons, stress granules (SG) are another barrier to viral infection by inducing translation arrest. To combat SG activity, viruses have evolved mechanisms to disrupt formation and disassemble these complexes. Our prior studies identified residues in SARS-CoV-2 NSP3 (Y138/F145) and nucleocapsid (F17) that independently antagonize SG activity. Disrupting these key residues in NSP3 or nucleocapsid attenuated viral replication, but only modestly impacted in vivo pathogenesis suggesting overlap in SG antagonism partially compensate for the individual losses. In this study, we evaluated a SARS-CoV-2 mutant (YF/F17A) that combines the NSP3 and N mutations. We find that loss of both SG antagonizing functions attenuates SARS-CoV-2 replication in vitro. While no changes are seen in type I IFN sensitivity, attenuation corresponds to increased induction of SGs. Importantly, the SARS-CoV-2 YF/F17A mutant has significant attenuation in vivo with reduced viral replication, less weight loss, and limited immune pathology. Notably, infection with the YF/F17A mutant stimulated less interferon and inflammation. Despite these muted host responses, the YF/F17A mutant stimulated robust protection against subsequent challenge with WT SARS-CoV-2. Overall, the study highlights the importance of SG control for SARS-CoV-2 infection and offers a novel, interferon independent target for vaccination and therapeutic treatment going forward. ImportanceThis study demonstrates that SARS-CoV-2 uses multiple mechanisms to block host stress granules during infection. Knocking out both N and NSP3 mediated antagonism of stress granules attenuates viral replication and disease caused by SARS-CoV-2. Importantly, while most therapeutics target key viral processes or induce interferon pathways, this study shows stress granule activation as a novel approach to attenuate and treat coronavirus infection.

microbiology↗

bioRxiv2025

Key residues in SARS-CoV-2 NSP3 hyper variable region are necessary to modulate early stress granule activity.

Antagonism of the host responses that limits viral replication is critical to the success of infection. Recently, we identified that the hypervariable region (HVR) of SARS-CoV-2 NSP3 binds to FXR1 and disrupts stress granule formation during the early stages of infection. Despite variation across the rest of the HVR, a 20-amino acid region, highly conserved in the Sarbecovirus family, is required for NSP3-FXR1 binding, but the critical residues remained unresolved. In this study, we explore the individual residues in NSP3 driving FXR1 binding and determine their impact on viral replication, pathogenesis, and stress granule formation. Our results indicate that the tyrosine at position 138 (Y138) and a phenylalanine at position 145 (F145) are required for FXR1 binding and affinity. Using reverse genetics, we showed mutating NSP3 Y138A/F145A (YF mutant) reduced viral replication in vitro and in vivo. Importantly, we demonstrate that attenuation is not due to differential type I interferon responses, but rather loss of stress granule control by the NSP3 mutant as compared to WT. Together, our findings demonstrate the importance of Y138 and F145 within the NSP3-HVR in regulating stress granule formation at the early times post infection. IMPORTANCEStress granules play a key role in host-antiviral defenses and viruses have developed strategies to antagonize their activity. For SARS-CoV-2, the virus has two proteins that antagonize stress granules with NSP3 acting early and nucleocapsid acting at late times. Here, we show that key NSP3 residues Y138 and F145, conserved across the Sarbecovirus family, are necessary to bind FXR1 and disrupt its activity in stress granule formation. Mutating these residues results in attenuation of SARS-CoV-2 replication and induces stress granule formation at early times post infection. These results show the importance of these NSP3 residues in disrupting stress granule formation early and highlight multiple approaches SARS-CoV-2 uses to antagonize stress granule activation.

microbiology↗