SIRT5 is a proviral factor that interacts with SARS-CoV-2 Nsp14 protein

• Published in: PLoS pathogens 2022-09, Vol.18 (9), p.e1010811
• Main Authors: Walter, Marius, Chen, Irene P, Vallejo-Gracia, Albert, Kim, Ik-Jung, Bielska, Olga, Lam, Victor L, Hayashi, Jennifer M, Cruz, Andrew, Shah, Samah, Soveg, Frank W, Gross, John D, Krogan, Nevan J, Jerome, Keith R, Schilling, Birgit, Ott, Melanie, Verdin, Eric
• Format: Article
• Language: English
• Subjects: Aging; Antiviral Agents; Biology and life sciences; Cell culture; Coronaviruses; COVID-19; Editing; Exoribonucleases - metabolism; Genomes; Health aspects; Histones; Humans; Hypotheses; Infections; Innate immunity; Lysine; Medicine and health sciences; Metabolism; Methyltransferase; Methyltransferases - metabolism; Mitochondria; NAD; Physical Sciences; Plasmids; Protein turnover; Proteins; Proviruses; Replication; Research and Analysis Methods; RNA polymerase; RNA, Viral - metabolism; SARS-CoV-2; Scientific imaging; Severe acute respiratory syndrome; Severe acute respiratory syndrome coronavirus 2; Sirtuins - genetics; Therapeutic applications; Transcription factors; Viral diseases; Viral infections; Viral Nonstructural Proteins - metabolism
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1010811

SARS-CoV-2 non-structural protein Nsp14 is a highly conserved enzyme necessary for viral replication. Nsp14 forms a stable complex with non-structural protein Nsp10 and exhibits exoribonuclease and N7-methyltransferase activities. Protein-interactome studies identified human sirtuin 5 (SIRT5) as a putative binding partner of Nsp14. SIRT5 is an NAD-dependent protein deacylase critical for cellular metabolism that removes succinyl and malonyl groups from lysine residues. Here we investigated the nature of this interaction and the role of SIRT5 during SARS-CoV-2 infection. We showed that SIRT5 interacts with Nsp14, but not with Nsp10, suggesting that SIRT5 and Nsp10 are parts of separate complexes. We found that SIRT5 catalytic domain is necessary for the interaction with Nsp14, but that Nsp14 does not appear to be directly deacylated by SIRT5. Furthermore, knock-out of SIRT5 or treatment with specific SIRT5 inhibitors reduced SARS-CoV-2 viral levels in cell-culture experiments. SIRT5 knock-out cells expressed higher basal levels of innate immunity markers and mounted a stronger antiviral response, independently of the Mitochondrial Antiviral Signaling Protein MAVS. Our results indicate that SIRT5 is a proviral factor necessary for efficient viral replication, which opens novel avenues for therapeutic interventions.