A chemoproteomics approach to discover regulators of innate immune signaling

Viral dsRNA binds to Retinoic acid Inducible Gene I (RIG-I) Like Receptors (RLRs), promoting the production of Interferon (IFN). Interferon then stimulates the innate and adaptive immune system in an autocrine and paracrine manner. Outside of conical pathways, regulators of the interferon (IFN) activation/response system are poorly characterized. In this study, we used a discovery-biased approach to identify Kinases that are part of the interferon system. Differential changes in phosphorylation sites, in the context of dsRNA RIG-I stimulation, were identified with unbiased mass-spec biased phospho-proteomics. We then computationally identified several Kinases upregulated after RIG-I stimulation from phospho-proteomics data. A Chemoproteomics screen was then used to characterize the altered interferon response in the presence of Kinases inhibitors for the upregulated kinases. Combining unbiased phosphoproteomics with a chemoproteomics screen, we identified several potentially novel regulators of the Interferon system whose inhibition blocked the production of Interferon Stimulated Genes.