UBE2O-mediated monoubiquitination licenses NLRP6 inflammasome activation in the intestine.

The NLRP6 inflammasome in intestinal epithelial cells (IECs) is a key sentinel of enteric pathogens, yet its activation mechanism remains enigmatic. Here, we identify monoubiquitination as a critical post-translational switch for NLRP6 inflammasome activation. We demonstrate that the E3 ligase UBE2O catalyzes dual-site monoubiquitination of NLRP6: at K680-687 to drive oligomerization via a conformational change, and at K115/130 within the nuclear localization signal to enforce cytoplasmic sequestration through steric hindrance. Mice harboring UBE2O deficiency or monoubiquitination-resistant NLRP6 mutations exhibit defective inflammasome activation and heightened susceptibility to rotavirus and Citrobacter rodentium infection. Furthermore, the UBE2O inhibitor arsenic trioxide suppresses NLRP6-dependent interleukin (IL)-18 secretion in acute promyelocytic leukemia (APL) patients. Thus, UBE2O-mediated dual-site monoubiquitination emerges as a central mechanism licensing NLRP6 inflammasome activation, revealing a new target for modulating intestinal immunity.