The mechanism of DNA sensor cGAS-STING regulating autophagy-related signal pathways

Cyclic GMP-AMP synthase (cGAS) serves as a DNA sensor for recognizing and binding microbial or self-DNA molecules in cells. Upon binding DNA, cGAS produces the second messenger cGAMP to activate the stimulator of interferon genes (STING), which mediates the expression of type 1 interferons (IFN-I) and other cytokines. cGAS-STING-mediated signal pathway plays an important role in innate immune reaction against microbial infections as well as autoimmunity, tumor immunology, and cellular senescence. During this process, cGAS regulates DNA damage repair and induces STING-mediated NF-κB and MAPK signal pathways in autophagy and lysosome-dependent cell apoptosis. However, the molecular mechanisms of cGAS-STING-mediated autophagy still need to be explored. Here, we found that cGAS-STING promotes autophagy by influencing multiple autophagy-related signal pathways: First, cGAS-STING promotes autophagy by inhibiting the mTOR signaling pathway; Second, cGAS-STING affects autophagy by regulating autophagy-related proteins that are also involved in cGAS-STING-mediated IFN-I and NF-κB signaling pathways; Third, the Bcl2 can interact with cGAS and STING to induce cGAS-STING-mediated up-regulation of IFN-I signaling pathway and down-regulation of NF-κB. In addition, we also found that USP19 can significantly reduce the K11-linked ubiquitination of STING in the process of autophagy. Our findings unveiled the functional role and the mechanism of cGAS-STING signaling in regulating autophagy.