Background：As the sensor component of the NLRP1 inflammasome, plays a crucial role in innate immunity and inflammation. In response to pathogens and other damage-associated signals, initiates the formation of the inflammasome polymeric complex, made of NLRP1, CASP1, and possibly PYCARD. Recruitment of proCASP1 to the inflammasome promotes its activation and CASP1-catalyzed IL1B and IL18 maturation and secretion in the extracellular milieu. Activation of NLRP1 inflammasome is also required for HMGB1 secretion. The active cytokines and HMGB1 stimulate inflammatory responses. Inflammasomes can also induce pyroptosis, an inflammatory form of programmed cell death(PubMed:22665479, PubMed:17418785). May be activated by muramyl dipeptide(MDP), a fragment of bacterial peptidoglycan, in a NOD2-dependent manner(PubMed:18511561). Contrary to its mouse ortholog, not activated by Bacillus anthracis lethal toxin(PubMed:19651869). It is unclear whether isoform 2 is involved in inflammasome formation. It is not cleaved within the FIIND domain, does not assemble into specks, nor promote IL1B release(PubMed:22665479). However, in an vitro cell-free system, it has been shown to be activated by MDP(PubMed:17349957). Binds ATP(PubMed:11113115, PubMed:15212762).
