Stimulator of Interferon Gene(Sting,TMEM173) belongs to the TMEM173 family. STING is 379 amino acids (aa) in length. It contains an N-terminal cytoplasmic region (aa 1-20), four transmembrane segments (aa 21-173), and a C-terminal cytoplasmic domain (aa 174-379). It ubiquitously expressed in skin endothelial cells, alveolar type 2 pneumocytes, bronchial epithelium and alveolar macrophagesand. Its subunit structure associated with the MHC-II complex and Interacts with DDX58/RIG-I, MAVS and SSR2, RNF5 and TRIM56 along with TBK1. This type of protein often uses as facilitator of innate immune signaling that acts as a sensor of cytosolic DNA from bacteria and viruses and promotes the production of type I interferon.