New insights in caspase-11 functions in noncanonical inflammasome signalling

Inflammasomes are multi-protein complexes that play a crucial role in innate immunity. They are assembled by cytosolic sensors of the Nucleotide-binding domain and Leucine-rich repeat containing Receptor (NLR) and PYrin and HIN (PYHIN) domain-containing protein families upon sensing various pathogens and danger signals. Inflammasome formation culminates in caspase-1 activation, which causes the cleavage of pro-IL-1β and pro- IL-18 into active cytokines; this eventually results in the induction of an inflammatory cell death called pyroptosis. Recent data using Gram-negative bacteria suggests a role for caspase-11 not only in NLRP3 inflammasome activation but also in a caspase-1- and inflammasome-independent cell death. This novel caspase-11-dependent pathway is critical to control infection by Gram-negative bacteria and has been named the noncanonical inflammasome.