Fig. 2.

Evolution of the cGAS-STING pathway. a Comparison of the functional domains in cGAS and STING between invertebrate (anemone) and vertebrate (human) species. Compared with human cGAS, anemone cGAS has a shorter N terminal and lacks the zinc-ribbon finger, both of which are involved in DNA binding in vertebrate cGAS. The C-terminal tail, which is essential for IFN induction in vertebrate STING, is also absent in anemone STING. b Currently identified cGAS-STING pathway in different species. While the cGAS-STING pathways in different species share a similar framework, there are two notable observations: firstly, no studies have suggested that invertebrate cGAS could detect DNA as vertebrate cGAS do, and the function of invertebrate cGAS remains unclear; secondly, the cGAS-STING pathway seems to have acquired more antipathogen methods during evolution