Authorship note: RJP, CT, and CJR are co-first authors. Conflict of interest: KDGP is chief scientific adviser of Dimerix Limited, a spin-off company of The University of Western Australia that has been assigned the rights to Receptor-HIT. KDGP is an inventor on patents covering the technology (World Intellectual Property [WIPO] patent no. WO/2008/055313, held by Dimerix Limited) and is a shareholder of Dimerix Limited.

Viperin is an interferon‐inducible protein that is pivotal for eliciting an effective immune response against an array of diverse viral pathogens. Here we describe a mechanism of viperin’s broad antiviral activity by demonstrating the protein’s ability to synergistically enhance the innate immune dsDNA signaling pathway to limit viral infection. Viperin co‐localized with the key signaling molecules of the innate immune dsDNA sensing pathway, STING and TBK1; binding directly to STING and inducing enhanced K63‐linked polyubiquitination of TBK1. Subsequent analysis identified viperin’s necessity to bind the cytosolic iron‐sulfur assembly component 2A, to prolong its enhancement of the type‐I interferon response to aberrant dsDNA. Here we show that viperin facilitates the formation of a signaling enhanceosome, to coordinate efficient signal transduction following activation of the dsDNA signaling pathway, which results in an enhanced antiviral state. We also provide evidence for viperin’s radical SAM enzymatic activity to self‐limit its immunomodulatory functions. These data further define viperin’s role as a positive regulator of innate immune signaling, offering a mechanism of viperin’s broad antiviral capacity.

The role of interferon and interferon stimulated genes (ISG) in limiting bacterial infection is controversial, and the role of individual ISGs in the control of the bacterial life-cycle is limited. Viperin, is a broad acting anti-viral ISGs, which restricts multiple viral pathogens with diverse mechanisms. Viperin is upregulated early in some bacterial infections, and using the intracellular bacterial pathogen, S. flexneri, we have shown for the first time that viperin inhibits the intracellular bacterial life cycle. S. flexneri replication in cultured cells induced a predominantly type I interferon response, with an early increase in viperin expression. Ectopic expression of viperin limited S. flexneri cellular numbers by as much as 80% at 5hrs post invasion, with similar results also obtained for the intracellular pathogen, Listeria monocytogenes. Analysis of viperins functional domains required for anti-bacterial activity revealed the importance of both viperin’s N-terminal, and its radical SAM enzymatic function. Live imaging of S. flexneri revealed impeded entry into viperin expressing cells, which corresponded to a loss of cellular cholesterol. This data further defines viperin’s multi-functional role, to include the ability to limit intracellular bacteria; and highlights the role of ISGs and the type I IFN response in the control of bacterial pathogens.

Viperin is an interferon-inducible protein that is pivotal for eliciting an effective immune response against an array of diverse viral pathogens. Here we describe a mechanism of viperin's broad antiviral activity by demonstrating the protein's ability to synergistically enhance the innate immune dsDNA signalling pathway to limit viral infection. Viperin colocalised with the key signalling molecules of the innate immune dsDNA sensing pathway, STING and TBK1; binding directly to STING and inducing enhanced K63-linked polyubiquitination of TBK1. Subsequent analysis identified viperin's necessity to bind the cytosolic iron-sulphur assembly component 2A, to prolong its enhancement of the type-I interferon response to aberrant dsDNA. Here we show that viperin facilitates the formation of a signalling enhanceosome, to coordinate efficient signal transduction following activation of the dsDNA signalling pathway; which results in an enhanced antiviral state. We also provide evidence for viperin's radical SAM enzymatic activity to self-limit its immunomodulatory functions. This data further defines viperin's role as a positive regulator of innate immune signalling, offering a mechanism of viperin's broad antiviral capacity.Key words (maximum 5, in alphabetical order): CIA2A/interferon/radical SAM enzyme/STING/viperin

Myocardial perfusion imaging with RTP improves the detection of CAD during both DSE and TESE. During TESE, the subendocardial perfusion defects improve WM sensitivity by delineating subendocardial WM abnormalities.