p53 degradation by a coronavirus papain-like protease suppresses type I interferon signaling

Area of Science:

• Virology
• Immunology
• Molecular Biology

Background:

• Human coronaviruses cause severe disease through viral replication and immunopathology.
• Coronavirus papain-like proteases (PLPs) are known innate immune suppressors, but their mechanism is unclear.
• Understanding viral evasion strategies is crucial for developing antiviral therapies.

Purpose of the Study:

• To elucidate the molecular mechanism by which coronavirus PLPs inhibit the innate immune response.
• To investigate the role of HCoV-NL63 PLP2 in regulating host cell proteins involved in immunity.
• To identify key host-pathogen interactions in coronavirus infection.

Main Methods:

• Biochemical assays to assess deubiquitination and protein stabilization.
• Western blotting to detect protein levels of MDM2 and p53.
• Gene expression analysis to identify target genes of p53, including IRF7.
• Cell-based assays to evaluate antiviral responses and apoptosis.

Main Results:

• HCoV-NL63 PLP2 deubiquitinates and stabilizes MDM2, leading to p53 proteasomal degradation.
• IRF7 is identified as a direct target gene of p53, mediating type I interferon production.
• PLP2-induced p53 degradation inhibits the p53-IRF7-IFNβ antiviral signaling pathway.

Conclusions:

• Coronavirus PLP2 actively suppresses the host's innate antiviral response by degrading p53.
• This viral strategy disrupts the p53-IRF7-IFNβ axis, facilitating viral replication.
• Targeting PLPs could be a potential therapeutic strategy against coronavirus infections.