NACHT, LRR and PYD domains-containing protein 3 (NALP3) also known by cryopyrin is a protein that in humans is encoded by the NLRP3 gene located on the long arm of chromosome 1.
NALP3 is expressed predominantly in macrophages and as a component of the inflammasome, detects products of damaged cells such as extracellular ATP and crystalline uric acid. Activated NALP3 in turn triggers an immune response. Mutations in the NLRP3 gene are associated with a number of organ specific autoimmune diseases.