Cyclic GMP-AMP synthase (cGAS, cGAMP synthase), belonging to the nucleotidyltransferase family, is a cytosolic DNA sensor that activates a type-I interferon response. It is part of the cGAS-STING DNA sensing pathway. It binds to microbial DNA as well as self DNA that invades the

cytoplasm In cell biology, the cytoplasm is all of the material within a eukaryotic cell, enclosed by the cell membrane, except for the cell nucleus. The material inside the nucleus and contained within the nuclear membrane is termed the nucleoplasm. The ...

, and catalyzes cGAMP synthesis. cGAMP then functions as a

second messenger Second messengers are intracellular signaling molecules released by the cell in response to exposure to extracellular signaling molecules—the first messengers. (Intercellular signals, a non-local form or cell signaling, encompassing both first me ...

that binds to and activates the

endoplasmic reticulum The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...

protein

STING Sting may refer to: * Stinger or sting, a structure of an animal to inject venom, or the injury produced by a stinger * Irritating hairs or prickles of a stinging plant, or the plant itself Fictional characters and entities * Sting (Middle-eart ...

to trigger type-I IFNs production. Mice lacking cGAS are more vulnerable to lethal infection by DNA viruses and

RNA virus An RNA virus is a virusother than a retrovirusthat has ribonucleic acid (RNA) as its genetic material. The nucleic acid is usually single-stranded RNA ( ssRNA) but it may be double-stranded (dsRNA). Notable human diseases caused by RNA viruses ...

es. In addition, cGAS has been shown to be an innate immune sensor of retroviruses including

HIV The human immunodeficiency viruses (HIV) are two species of ''Lentivirus'' (a subgroup of retrovirus) that infect humans. Over time, they cause acquired immunodeficiency syndrome (AIDS), a condition in which progressive failure of the immune ...

. The human gene encoding cGAS is MB21D1 on chromosome 6.

References

Transferases {{transferase-stub