SARS-CoV-2 Orf6 hijacks Nup98 to block STAT nuclear import and antagonize interferon signaling

Miorin, Lisa; Kehrer, Thomas; Sanchez-Aparicio, Maria Teresa; Zhang, Ke; Cohen, Phillip; Patel, Roosheel S.; Cupic, Anastasija; Makio, Tadashi; Mei, Menghan; Moreno, Elena; Danziger, Oded; White, Kris M.; Rathnasinghe, Raveen; Uccellini, Melissa; Gao, Shengyan; Aydillo, Teresa; Mena, Ignacio; Yin, Xin; Martin-Sancho, Laura; Krogan, Nevan J.; Chanda, Sumit K.; Schotsaert, Michael; Wozniak, Richard W.; Ren, Yi; Rosenberg, Brad R.; Fontoura, Beatriz M. A.; García-Sastre, Adolfo

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing coronavirus disease 2019 (COVID-19) pandemic that is a serious global health problem. Evasion of IFN-mediated antiviral signaling is a common defense strategy that pathogenic viruses use to replicate and propagate in their host. In this study, we show that SARS-CoV-2 is able to efficiently block STAT1 and STAT2 nuclear translocation in order to impair transcriptional induction of IFN-stimulated genes (ISGs). Our results demonstrate that the viral accessory protein Orf6 exerts this anti-IFN activity. We found that SARS-CoV-2 Orf6 localizes at the nuclear pore complex (NPC) and directly interacts with Nup98-Rae1 via its C-terminal domain to impair docking of cargo-receptor (karyopherin/importin) complex and disrupt nuclear import. In addition, we show that a methionine-to-arginine substitution at residue 58 impairs Orf6 binding to the Nup98-Rae1 complex and abolishes its IFN antagonistic function. All together our data unravel a mechanism of viral antagonism in which a virus hijacks the Nup98-Rae1 complex to overcome the antiviral action of IFN.