cGAS Recombinant Rabbit mAb (S-5406)

cGAS is a widely expressed DNA sensor in the mammalian cytoplasm that serves as a critical sentinel of the innate immune system, responsible for recognizing invading pathogen DNA or self-DNA that has leaked into the cytosol. This protein consists of approximately 522 amino acids, containing a conserved nucleotidyltransferase (NTase) core domain flanked by regulatory regions, with its catalytic activity dependent on binding to double-stranded DNA: upon recognition and binding of DNA, cGAS undergoes conformational rearrangement and catalyzes the production of the second messenger molecule cyclic GMP-AMP (cGAMP) from ATP and GTP. The newly synthesized cGAMP subsequently binds to and activates the adaptor protein STING on the endoplasmic reticulum, which in turn initiates the TBK1-IRF3 signaling cascade, inducing the transcriptional expression of type I interferons and pro-inflammatory cytokines, thereby establishing the first line of defense against microbial infections. Beyond antiviral defense, the cGAS-cGAMP-STING pathway also plays a significant role in anti-tumor immune surveillance, as genomic instability and DNA damage within tumor cells lead to micronucleus formation and release of DNA into the cytosol, thereby activating this pathway to recruit immune cells for tumor clearance. However, dysregulation of this pathway exhibits a "double-edged sword" effect: excessive or aberrant activation of cGAS can trigger autoinflammatory diseases such as Aicardi-Goutières syndrome, and even contributes to neurodegenerative diseases (such as Alzheimer's disease) and aging-related chronic inflammation. Therefore, cGAS is not only a key molecule for understanding the fundamental mechanisms of immune recognition, but has also emerged as a novel drug target for anti-infection, anti-tumor therapy, and the treatment of autoimmune diseases.