Figure 2. Canonical and non-canonical inflammasome activation pathways.
Canonical inflammasomes including NLRP3, AIM2, and NLRC4 activate caspase-1. NLRP3 or AIM2 recruits caspase-1 through the adaptor protein ASC via Pyrin-Pyrin homotypic interactions. The activated caspase-1 results in its proteolytic maturation to the p10 and p20 fragments, and subsequent IL-1β and IL-18 cleavage and secretion. NLRC4 contains a CARD domain and directly binds to the CARD of caspase-1 through homotypic interaction, triggering cytokine (IL-1β and IL-18) maturation and pyroptosis. Non-canonical inflammasome activation leads to caspase-11-dependent pyroptosis. Caspase-11 activation also triggers NLRP3 activation via an unknown mechanism (not shown).