Suppresses TNF- and CD40-induced NFKB1 activity at the level of the IKK complex, by inhibiting NFKBIA degradation induced by TNF. When associated with PYCARD, activates CASP1, leading to the secretion of mature pro-inflammatory cytokine IL1B. May be a component of the inflammasome, a protein complex which also includes PYCARD, CARD8 and CASP1 and whose function would be the activation of pro-inflammatory caspases. Interacts with CHUK (PubMed:15456791). Interacts with IKBKB (PubMed:15456791). Interacts with IKBKG (PubMed:15456791). Interacts with MEFV (PubMed:17431422). Interacts with PYCARD (PubMed:15030775, PubMed:15456791). Interacts (via pyrin domain) with PYDC2 (PubMed:17178784). Interacts with CARD8 (PubMed:15030775). Expressed at high levels in lung, placenta and thymus and at lower levels in ovary, intestine and brain (PubMed:15456791). Highly abundant in oocytes and early embryos, however poorly expressed in somatic tissues such as brain, kidney, liver and spinal cord (PubMed:30877238). By interferons and bacterial lipopolysaccharides (LPS). When isolated, the NACHT domain is involved in interaction with CARD8. This interaction is not detected for the full-length protein, maybe due to autoinhibition, this inhibition might by relieved by an inducible change in protein folding. The pyrin domain is necessary and sufficient for suppression of NFKB1 activation induced by TNF and for inducing IL1B secretion in collaboration with caspase-1. It is involved in interaction with PYCARD. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the NLRP family. Erroneous prediction of the initiator methionine.