Selenoprotein K enhances STING oligomerization to facilitate antiviral response

Author summarySelenoproteins are crucial for various physiological processes. Most selenoproteins locate in the cytoplasm and regulate redox pathways to protect cells from oxidative stress. However, the potential roles of transmembrane selenoproteins are largely unknown. Here, we identified Selenoprotein K (SELENOK), an ER-located transmembrane selenoprotein, as a physiological enhancer of STING-dependent antiviral innate immunity. SELENOK is upregulated during viral infection and enhances STING oligomerization to facilitate the activation of the cGAS-STING pathway and suppress viral replication. These results will be valuable for understanding the physiological roles of transmembrane selenoproteins in immunity. Furthermore, as aberrant STING activation has been linked to various pathological conditions, control of STING activity by SELENOK may be a prime therapeutic strategy. Stimulator-of-interferon gene (STING) is a vital element of the innate immune system against DNA viruses. Optimal activation of STING is crucial for maintaining immune homeostasis and eliminating invading viruses, and the oligomerization of STING is an essential prerequisite for STING activation. However, the mechanism of cGAMP-induced STING oligomerization in ER remains unclear. Selenoproteins are crucial for various physiological processes. Here, we identified that the endoplasmic reticulum (ER)-located transmembrane selenoprotein K (SELENOK) was induced during virus infection and facilitated innate immune responses against herpes simplex virus-1 (HSV-1). Mechanistically, SELENOK interacts with STING in the ER and promotes STING oligomerization, which in turn promotes its translocation from the ER to the Golgi. Consequently, Selenok deficiency suppresses STING-dependent innate responses and facilitates viral replication in vivo. Thus, the control of STING activation by selenium-mediated SELENOK expression will be a priming therapeutic strategy for the treatment of STING-associated diseases.

Automated summary

In this study, we identified a transmembrane selenoprotein, SELENOK, located in the endoplasmic reticulum (ER), which is induced during viral infection and enhances innate immune response against herpes simplex virus-1 (HSV-1) by promoting STING oligomerization. SELENOK interacts with STING, facilitating its translocation from the ER to the Golgi. Thus, controlling STING activation through selenium-mediated SELENOK expression could be a potential therapeutic strategy for STING-associated diseases.