Acts as the sensor component of the NLRP1 inflammasome, which mediates inflammasome activation in response to various pathogen- associated signals, leading to subsequent pyroptosis (PubMed:12191486, PubMed:17349957, PubMed:22665479, PubMed:27662089, PubMed:31484767, PubMed:33093214, PubMed:33410748, PubMed:33731929, PubMed:33731932, PubMed:35857590). Inflammasomes are supramolecular complexes that assemble in the cytosol in response to pathogens and other damage- associated signals and play critical roles in innate immunity and inflammation (PubMed:12191486, PubMed:17349957, PubMed:22665479). Acts as a recognition receptor (PRR): recognizes specific pathogens and other damage-associated signals, such as cleavage by some human enteroviruses and rhinoviruses, double-stranded RNA, UV-B irradiation, or Val-boroPro inhibitor, and mediates the formation of the inflammasome polymeric complex composed of NLRP1, CASP1 and PYCARD/ASC (PubMed:12191486, PubMed:17349957, PubMed:22665479, PubMed:25562666, PubMed:30096351, PubMed:30291141, PubMed:33093214, PubMed:33243852, PubMed:33410748, PubMed:35857590). In response to pathogen-associated signals, the N-terminal part of NLRP1 is degraded by the proteasome, releasing the cleaved C-terminal part of the protein (NACHT, LRR and PYD domains-containing protein 1, C-terminus), which polymerizes and associates with PYCARD/ASC to initiate the formation of the inflammasome complex: the NLRP1 inflammasome recruits pro-caspase-1 (proCASP1) and promotes caspase-1 (CASP1) activation, which subsequently cleaves and activates inflammatory cytokines IL1B and IL18 and gasdermin-D (GSDMD), leading to pyroptosis (PubMed:12191486, PubMed:17349957, PubMed:22665479, PubMed:32051255, PubMed:33093214). In the absence of GSDMD expression, the NLRP1 inflammasome is able to recruit and activate CASP8, leading to activation of gasdermin-E (GSDME) (PubMed:33852854, PubMed:35594856). Activation of NLRP1 inflammasome is also required for HMGB1 secretion; the active cytokines and HMGB1 stimulate inflammatory responses (PubMed:22801494). Binds ATP and shows ATPase activity (PubMed:11113115, PubMed:15212762, PubMed:33243852). Plays an important role in antiviral immunity and inflammation in the human airway epithelium (PubMed:33093214). Specifically recognizes a number of pathogen-associated signals: upon infection by human rhinoviruses 14 and 16 (HRV-14 and HRV-16), NLRP1 is cleaved and activated which triggers NLRP1-dependent inflammasome activation and IL18 secretion (PubMed:33093214). Positive-strand RNA viruses, such as Semliki forest virus and long dsRNA activate the NLRP1 inflammasome, triggering IL1B release in a NLRP1-dependent fashion (PubMed:33243852). Acts as a direct sensor for long dsRNA and thus RNA virus infection (PubMed:33243852). May also be activated by muramyl dipeptide (MDP), a fragment of bacterial peptidoglycan, in a NOD2- dependent manner (PubMed:18511561). The NLRP1 inflammasome is also activated in response to UV-B irradiation causing ribosome collisions: ribosome collisions cause phosphorylation and activation of NLRP1 in a MAP3K20-dependent manner, leading to pyroptosis (PubMed:35857590). {ECO:0000269|PubMed:11113115, ECO:0000269|PubMed:12191486, ECO:0000269|PubMed:15212762, ECO:0000269|PubMed:17349957, ECO:0000269|PubMed:18511561, ECO:0000269|PubMed:22665479, ECO:0000269|PubMed:22801494, ECO:0000269|PubMed:25562666, ECO:0000269|PubMed:27662089, ECO:0000269|PubMed:30096351, ECO:0000269|PubMed:30291141, ECO:0000269|PubMed:31484767, ECO:0000269|PubMed:32051255, ECO:0000269|PubMed:33093214, ECO:0000269|PubMed:33243852, ECO:0000269|PubMed:33410748, ECO:0000269|PubMed:33731929, ECO:0000269|PubMed:33731932, ECO:0000269|PubMed:33852854, ECO:0000269|PubMed:35594856, ECO:0000269|PubMed:35857590}. [NACHT, LRR and PYD domains-containing protein 1]: Constitutes the precursor of the NLRP1 inflammasome, which mediates autoproteolytic processing within the FIIND domain to generate the N- terminal and C-terminal parts, which are associated non-covalently in absence of pathogens and other damage-associated signals. . [NACHT, LRR and PYD domains-containing protein 1, N- terminus]: Regulatory part that prevents formation of the NLRP1 inflammasome: in absence of pathogens and other damage-associated signals, interacts with the C-terminal part of NLRP1 (NACHT, LRR and PYD domains-containing protein 1, C-terminus), preventing activation of the NLRP1 inflammasome (PubMed:33093214). In response to pathogen- associated signals, this part is ubiquitinated and degraded by the proteasome, releasing the cleaved C-terminal part of the protein, which polymerizes and forms the NLRP1 inflammasome (PubMed:33093214). . [NACHT, LRR and PYD domains-containing protein 1, C- terminus]: Constitutes the active part of the NLRP1 inflammasome (PubMed:33093214, PubMed:33731929, PubMed:33731932). In absence of pathogens and other damage-associated signals, interacts with the N- terminal part of NLRP1 (NACHT, LRR and PYD domains-containing protein 1, N-terminus), preventing activation of the NLRP1 inflammasome (PubMed:33093214). In response to pathogen-associated signals, the N- terminal part of NLRP1 is degraded by the proteasome, releasing this form, which polymerizes and associates with PYCARD/ASC to form of the NLRP1 inflammasome complex: the NLRP1 inflammasome complex then directly recruits pro-caspase-1 (proCASP1) and promotes caspase-1 (CASP1) activation, leading to gasdermin-D (GSDMD) cleavage and subsequent pyroptosis (PubMed:33093214). {ECO:0000269|PubMed:33093214, ECO:0000269|PubMed:33731929, ECO:0000269|PubMed:33731932}. [Isoform 2]: It is unclear whether 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). {ECO:0000269|PubMed:17349957, ECO:0000269|PubMed:22665479}. This is the function of Ensembl gene identifier ENSG00000091592 (NLRP1, NLR family pyrin domain containing 1).