Fig. 1.

cGAS–STING signalling pathway. Cytosolic DNA (either foreign or self) is recognized by cGAS, which converts ATP and GTP into the second messenger 2′,3′-cGAMP, and this messenger binds and activates STING located in the endoplasmic reticulum. STING translocates to the Golgi, where it recruits and induces the phosphorylation of IRF3 and IKK via TBK1. Cytosolic IRF3 dimerizes and enters the nucleus after phosphorylation, which results in induction of the transcription of IRF3 target genes and the release of type 1 IFNs. Parallel to IRF3 activation, STING also activates IKK, which induces the transcription of NF-κB transcription factors and the release of cytokines