The SUMOylation of ZIKA nonstructural protein 5 (NS5) influences its stability, its cellular localization and its interferon blocking activity
Anupriya Gautam1, Solene Grayo1, Dandan Ren1, Li Huang1, Emilie Carlot1, Bowen Duan1, Mathilde Ban1, Margot Enguehard1,2,3, Marie Cresson1,2, Lucie Cappuccio1,2, Carine Maisse2, Gang Long1, Ke Xu1 and Dimitri Lavillette1
1Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai 200031, China; 2Univ Lyon, INRA, UMR754 Viral infection and comparative pathogenesis, Université Claude Bernard Lyon 1, VetAgro Sup, F-69366 Lyon, France; 3Univ Lyon, CNRS UMR5557 Microbial ecology, Université Claude Bernard Lyon 1, INRA, UMR1418- F-69622, Villeurbanne, France
The factors that contributed to the emergence, spread and change in pathogenesis of ZIKV are not fully understood. Using sequence alignments of different ZIKV strains of a range of spatiotemporal history of isolation and representing African and Asian lineages, we identified possible differences in Lysine presence or position. Lysines are the target of important post translational modification (PTM) like Ubiquitination, Acetylation or Sumoylation. Recently, we and others demonstrated that the attachments of small ubiquitin-like modifier (SUMO) to some viral protein are important at different stages of the viral cycle. In order to identify potential SUMOylation, we expressed individually all ZIKV proteins in the presence of tagged SUMO and different proteins of this pathway. We identified NS5 as the sole ZIKV protein being SUMOylated in a classic mechanism, as recently illustrated with the DENV NS5 protein. Using RNA interference strategy, we found that changes in the SUMO cell machinery inhibit Zika replication. Using sequence alignments and site directed mutagenesis, we identified a SUMO interacting motif (SIM), well conserved among Flaviviruses. That is responsible for a non-covalent binding of SUMO protein in both African and Asian/American strains. Different NS5 SIM mutants that we generated showed both no SUMOylation and a severe defect in viral RNA replication. In addition, we found that the SUMOylation of NS5 regulates its ability to localize in punctuated structures in nuclei similar to PML nuclear bodies. Finally, SUMOylation-defective mutants failed to degrade STAT2 and cannot counteract host antiviral interferon signaling.
This is the first report showing that ZIKV NS5 SUMOylation is crucial for viral replication. The role of NS5 Lysine motifs in ZIKV virulence remains to be investigated. The SUMO cell machinery represents a possible target for drug development against ZIKV.