Cyclic GMP-AMP (cGAMP) synthase (cGAS) (161-522) is a truncated form of cGAS (Item No. 22810) that contains the nucleotidyltransferase and Mab21 domains.1 cGAS is a nucleotidyltransferase located in the cytosol that acts as a cytosolic DNA sensor to detect foreign DNA from microbial pathogens as part of the innate immune response.2,3 Upon binding to cytosolic DNA, cGAS produces the cyclic dinucleotide second messenger cGAMP, which activates stimulator of interferon genes (STING), lEAding to activation of the type I interferon (IFN) pathway.2,3,4 In vitro, fibroblasts, macrophages, and dendritic cells isolated from cGAS knockout (cGAS-/-) mice do not produce type I IFNs following DNA transfection or DNA virus infection.5 Similarly, cells containing a frame-shift mutation in the cGAS locus fail to mount an immune response to HIV and other retroviruses.6 In vivo, cGAS-/- mice infected with herpes simplex virus 1 (HSV-1) have lower levels of IFN- and IFN-, shorter survival times, and higher post-mortem levels of HSV-1 in the brain.5Technical InformationSynonymsC6orf15023-cGAMP SynthasecGAMP Synthaseh-cGASCyclic GMP-AMP SynthaseMab-21 domain-containing protein 1MB21D1Purity90% estimated by SDS-PAGESourceN-terminal histidine-tagged human cGAS protein (truncated), purified from E. coliAmino Acids161-522 (truncated)MW44.6 kDaFormulation50 mM HEPES, pH 8.0, 150 mM sodium chloride, 1 mM DTT, and 10% glycerolUniProt Accession Q8N884