AIM2 Forms a Complex with Pyrin and ZBP1 to Drive PANoptosis and Host Defence

Inflammasomes are important sentinels of innate immune defence, sensing pathogens and inducing cell death in infected cells. There are several inflammasome sensors that each detect and respond to a specific pathogen- or damage-associated molecular pattern (PAMP or DAMP, respectively). During infection, live pathogens can induce the release of multiple PAMPs and DAMPs, which can simultaneously engage multiple inflammasome sensors. Here we found that AIM2 regulates the innate immune sensors pyrin and ZBP1 to drive inflammatory signalling and a form of inflammatory cell death known as PANoptosis, and provide host protection during infections with herpes simplex virus 1 and Francisella novicida. We also observed that AIM2, pyrin and ZBP1 were members of a large multi-protein complex along with ASC, caspase-1, caspase-8, RIPK3, RIPK1 and FADD, that drove inflammatory cell death (PANoptosis). Collectively, our findings define a previously unknown regulatory and molecular interaction between AIM2, pyrin and ZBP1 that drives assembly of an AIM2-mediated multi-protein complex that we term the AIM2 PANoptosome and comprising multiple inflammasome sensors and cell death regulators. These results advance the understanding of the functions of these molecules in innate immunity and inflammatory cell death, suggesting new therapeutic targets for AIM2-, ZBP1- and pyrin-mediated diseases.