RT Journal Article SR Electronic T1 The Antiviral Enzyme, Viperin, Activates Protein Ubiquitination by the E3 Ubiquitin Ligase, TRAF6 JF bioRxiv FD Cold Spring Harbor Laboratory SP 2021.02.21.432004 DO 10.1101/2021.02.21.432004 A1 Ayesha M. Patel A1 E. Neil G. Marsh YR 2021 UL http://biorxiv.org/content/early/2021/02/22/2021.02.21.432004.abstract AB Viperin is a broadly conserved radical SAM enzyme that synthesizes the antiviral nucleotide ddhCTP. In higher animals viperin expression also accelerates the degradation of various cellular and viral proteins necessary for viral replication; however, the details of this process remain largely unknown. Here we show that viperin activates a component of the protein ubiquitination machinery, which plays an important role in both protein degradation and immune signaling pathways. We demonstrate that viperin binds the E3 ubiquitin ligase, TRAF6, which catalyzes K63-linked ubiquitination associated with immune signaling pathways. Viperin activates ubiquitin transfer by TRAF6 ~2.5-fold and causes a significant increase in polyubiquitinated forms of TRAF6 that are important for mediating signal transduction. Our observations both imply a role for viperin as an agonist of immune signaling and suggest that viperin may activate other K48-linked E3-ligases involved in targeting proteins for proteasomal degradation.Competing Interest StatementThe authors have declared no competing interest.