Listerin promotes cGAS protein degradation through the ESCRT pathway to negatively regulate cGAS-mediated immune response.

The enzyme cyclic GMP-AMP synthase (cGAS) is a key sensor for detecting misplaced double-stranded DNA (dsDNA) of genomic, mitochondrial, and microbial origin. It synthesizes 2'3'-cGAMP, which in turn activates the stimulator of interferon genes pathway, leading to the initiation of innate immune responses. Here, we identified Listerin as a negative regulator of cGAS-mediated innate immune response. We found that Listerin interacts with cGAS on endosomes and promotes its K63-linked ubiquitination through recruitment of the E3 ligase TRIM27. The polyubiquitinated cGAS is then recognized by the endosomal sorting complexes required for transport machinery and sorted into endosomes for degradation. Listerin deficiency enhances the innate antiviral response to herpes simplex virus 1 infection. Genetic deletion of Listerin also deteriorates the neuroinflammation and the ALS disease progress in an ALS mice model; overexpression of Listerin can robustly ameliorate disease progression in ALS mice. Thus, our work uncovers a mechanism for cGAS regulation and suggests that Listerin may be a promising therapeutic target for ALS disease.