This new article publication from Acta Pharmaceutica Sinica B , discusses how SARS-CoV-2 ORF10 hijacking ubiquitination machinery reveals potential unique drug targeting sites. Viruses often manipulate ubiquitination pathways to facilitate their replication and pathogenesis. CUL2 ZYG11B known as the substrate receptor of cullin-2 RING E3 ligase, is bound by SARS-CoV-2 ORF10 to increase its E3 ligase activity, leading to degradation of IFT46, a protein component of the intraflagellar transport (IFT) complex B.
This results in dysfunctional cilia, which explains certain symptoms that are specific to COVID-19. However, the precise molecular mechanism of how ORF10 recognizes CUL2 ZYG11B remains unknown. The authors of this article determined the crystal structure of CUL2 ZYG11B complexed with the N-terminal extension (NTE) of SARS-CoV-2 ORF10 (2.
9 Å). The structure reveals that the ORF10 N-terminal heptapeptide (NTH) mimics the Gly/N-degron to bind CUL2 ZYG11B . Mutagenesis studies identified key residues within ORF10 that are key players in its interaction with CUL2 ZYG11B both in ITC assay and in vivo cells.
In addition, enhancement of CUL2 ZYG11B activity for IFT46 degradation by which ORF10-mediated correlates with the binding affinity between ORF10 and CUL2 ZYG11B was proven. Finally, a Global Protein Stability system was used to show that the NTH of ORF10 mimics the Gly/N-degron motif, thereby binding competitively to CUL2 ZYG11B and inhibiting the degradation of target s.
