NALP4 is a 994aa cytoplasmic regulatory protein involved in inflammatory response. It belongs to the NLRP family and contains a PYD domain, eight LRR (leucine rich) repeats and a NACHT domain. Like other NALP proteins, NALP4 may also form multiprotein complexes called inflammasomes and thus may be involved in the activation of proinflammatory caspases and apoptosis. NALP4 is known to resemble Cryopyrin, a protein involved in hereditary hyperinflammation syndromes. Immunoblot and mutation analysis suggest that NALP4 inhibits the induction of NF-kB DNA-binding activity by the cytokine TNF and IL-1B through its PYD domain and also suppress IKKA activity via a mechanism that did not involve its PYD or LRR domain. It is widely expressed in most tissues including spleen, followed by placenta, lung, liver, kidney, pancreas, and thymus.