Suppression of SARS-CoV-2 nucleocapsid protein dimerization by ISGylation and its counteraction by viral PLpro

Wonjin Bang, Jaehyun Kim, Kanghun Seo, Jihyun Lee, Ji Ho Han, Daegyu Park, Jae Hwan Cho, Donghyuk Shin, Kyun Hwan Kim, Moon Jung Song, Jin Hyun Ahn

Research output: Contribution to journalArticlepeer-review

Abstract

Protein modification by the ubiquitin-like protein ISG15 (ISGylation) plays a crucial role in the immunological defense against viral infection. During severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, innate immune signaling proteins are ISGylated, facilitating innate immunity. However, whether SARS-CoV-2 proteins are direct substrates for ISGylation remains unclear. In this study, we investigated whether SARS-CoV-2 proteins undergo ISGylation and whether ISGylation affects viral protein function. Co-transfection ISGylation analysis of SARS-CoV-2 proteins showed that the nucleocapsid (N) protein is ISGylated at several sites. Herc5 promoted N ISGylation and interacted with N, indicating that Herc5 acts as an E3 ligase for N ISGylation. Lys-261 (K261) within the oligomerization domain of N was identified as a potential ISGylation site that is necessary for efficient ISGylation of N. K261 is positioned at the center of the dimer interface in the crystal structure of the C-terminal domain dimer and the ISGylated form of N showed reduced protein dimerization in pull-down analysis. Importantly, a recombinant virus expressing K261R mutant N showed enhanced resistance to interferon-β treatment compared to its parental virus. We also found that viral PLpro removes conjugated ISG15 from N. Our findings demonstrate that ISGylation of SARS-CoV-2 N inhibits protein dimerization, resulting in viral growth more susceptible to type I interferon responses, and that viral PLpro counteracts this ISG15-mediated antiviral activity by removing conjugated ISG15 from N.

Original languageEnglish
Article number1490944
JournalFrontiers in Microbiology
Volume15
DOIs
Publication statusPublished - 2024

Bibliographical note

Publisher Copyright:
Copyright © 2024 Bang, Kim, Seo, Lee, Han, Park, Cho, Shin, Kim, Song and Ahn.

All Science Journal Classification (ASJC) codes

  • Microbiology
  • Microbiology (medical)

Fingerprint

Dive into the research topics of 'Suppression of SARS-CoV-2 nucleocapsid protein dimerization by ISGylation and its counteraction by viral PLpro'. Together they form a unique fingerprint.

Cite this