Related Experiment Video
Updated: Jun 1, 2025

A Fluorogenic Peptide Cleavage Assay to Screen for Proteolytic Activity: Applications for coronavirus spike protein activation
Published on: January 9, 2019
The SARS-CoV-2 nucleocapsid protein interferes with the full enzymatic activation of UPF1 and its interaction with
Veronica Nuccetelli1,2, Makram Mghezzi-Habellah3, Séverine Deymier4
1Molecular Microbiology and Structural Biochemistry, MMSB-IBCP, CNRS UMR 5086 , Université Claude Bernard Lyon 1, F-69367 Lyon, France.
Abstract:
The nonsense-mediated mRNA decay (NMD) pathway triggers the degradation of defective mRNAs and governs the expression of mRNAs with specific characteristics. Current understanding indicates that NMD is often significantly suppressed during viral infections to protect the viral genome. In numerous viruses, this inhibition is achieved through direct or indirect interference with the RNA helicase UPF1, thereby promoting viral replication and enhancing pathogenesis. In this study, we employed biochemical, biophysical assays and cellular investigations to explore the interplay between UPF1 and the nucleocapsid (Np) protein of SARS-CoV-2. We evaluated their direct interaction and its impact on inhibiting cellular NMD. Furthermore, we characterized how this interaction affects UPF1's enzymatic function. Our findings demonstrate that Np inhibits the unwinding activity of UPF1 by physically obstructing its access to structured nucleic acid substrates. Additionally, we showed that Np binds directly to UPF2, disrupting the formation of the UPF1/UPF2 complex essential for NMD progression. Intriguingly, our research also uncovered a surprising pro-viral role of UPF1 and an antiviral function of UPF2. These results unveil a novel, multi-faceted mechanism by which SARS-CoV-2 evades the host's defenses and manipulates cellular components. This underscores the potential therapeutic strategy of targeting Np-UPF1/UPF2 interactions to treat COVID-19.
More Related Videos
Related Concept Videos
Nonsense-mediated mRNA Decay
Usually, Upf3 binds to an Exon Junction Complex (EJC) at mRNA splice sites. If a ribosome fully translates the mRNA,...
The Unfolded Protein Response
Regulation of the Unfolded Protein Response
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein....
Protein Complexes with Interchangeable Parts
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order...
Leaky Scanning

