FOSL1 Inhibits Type I Interferon Responses to Malaria and Viral Infections by Blocking TBK1 and TRAF3/TRIF Interactions

Abstract

Infections of pathogens can trigger vigorous host immune responses, including activation and production of type I interferon (IFN-I). In this study, we investigated the role of FOSL1, a molecule previously known as a transcription factor, in negatively regulating IFN-I responses to malaria and viral infections. We showed that FOSL1 was upregulated and translocated into the cytoplasm of cells after stimulation for IFN-I production. FOSL1 could affect TRAF3 and TRIF ubiquitination and consequently impaired the association of TRAF3, TRIF, and TBK1, leading to inhibition of IFN-I signaling. In vivo experiments with FOSL1 knockout chimeric mice further validated the negative role of FOSL1 in IFN-I production and antimicrobial responses. This report reveals a new functional role for FOSL1 in IFN-I signaling and dissects the mechanism by which FOSL1 regulates IFN-I responses to malaria and viral infections, which can be explored as a potential drug target for disease control and management.