Cyclic GMP AMP synthase

Cyclic GMP-AMP synthase (cGAS, cGAMP synthase), belonging to the nucleotidyltransferase family, is a cytosolic DNA sensor that activates the type-I interferon pathway. It binds to microbial DNA as well as self DNA that invades the cytoplasm, and catalyzes cGAMP synthesis. cGAMP then functions as a second messenger that binds to and activates the endoplasmic reticulum protein STING to trigger type-I IFNs production. Mice lacking cGAS were more vulnerable to lethal infection by DNA viruses. In addition, cGAS has been shown to be an innate immune sensor of retroviruses including HIV.