SARS-CoV-2 nucleocapsid protein promotes self-deacetylation by inducing HDAC6 to facilitate viral replication

The global outbreak of COVID-19 caused by the SARS-CoV-2 has led to millions of deaths. This unanticipated emergency has prompted virologists across the globe to delve deeper into the intricate dynamicity of the host-virus interface with an aim to identify antiviral targets and elucidate host and viral determinants of severe disease. The present study was undertaken to analyse the role of histone deacetylase 6 (HDAC6) in regulating SARS-CoV-2 infection. Gradual increase in HDAC6 expression was observed in different SARS-CoV-2-permissive cell lines following SARS-CoV-2 infection. The SARS-CoV-2 nucleocapsid protein (N protein) was identified as the primary viral factor responsible for upregulating HDAC6 expression. Downregulation of HDAC6 using shRNA or a specific inhibitor tubacin resulted in reduced viral replication suggesting proviral role of its deacetylase activity. Further investigations uncovered the interaction of HDAC6 with stress granule protein G3BP1 and N protein during infection. HDAC6-mediated deacetylation of SARS-CoV-2 N protein was found to be crucial for its association with G3BP1. This study provides valuable insights into the molecular mechanisms underlying the disruption of cytoplasmic stress granules during SARS-CoV-2 infection and highlights the significance of HDAC6 in the process.