NLRP3 and gram-negative bacterial infections: We observed comparable activation of ERK and NF-κB in WT and Casp6−/− BMDMs upon infection with E. coli or C. rodentium (Fig. 2, A and B), suggesting that CASP6 is dispensable for the priming step of gram-negative bacterial infection-induced CASP11-NLRP3 inflammasome activation.