Nucleotidyltransferase that catalyzes the formation of cyclic GMP-AMP (cGAMP) from ATP and GTP. Catalysis involves both the formation of a 2',5' phosphodiester linkage at the GpA step and the formation of a 3',5' phosphodiester linkage at the ApG step, producing c[G(2',5')pA(3',5')p]. Has antiviral activity by acting as a key cytosolic DNA sensor, the presence of double-stranded DNA (dsDNA) in the cytoplasm being a danger signal that triggers the immune responses. Binds cytosolic DNA directly, leading to activation and synthesis of cGAMP, a second messenger that binds to and activates TMEM173,STING, thereby triggering type-I interferon production. cGAMP can be transferred between cells by virtue of packaging within viral particles contributing to IFN-induction in newly infected cells in a cGAS-independent but TMEM173,STING-dependent manner (PubMed:26229115).
"Cyclic GMP-AMP synthase is a cytosolic DNA sensor that activates the type I interferon pathway."Sun L., Wu J., Du F., Chen X., Chen Z.J.Science 339:786-791(2013)
Research Topic:Others