NLR family pyrin domain containing 3 (NLRP3) (previously known as NACHT, LRR and PYD domains-containing protein 3 [NALP3] and cryopyrin), is a protein that in humans is encoded by the NLRP3 gene. NLRP3 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 NLRP3 in turn triggers an immune response. Mutations in the NLRP3 gene are associated with a number of organ specific autoimmune diseases. NLRP3 is a component of the innate immune system that functions as a pattern recognition receptor (PRR) that recognizes pathogen-associated molecular patterns (PAMPs). NLRP3 belongs to the NOD-like receptor (NLR) subfamily of PRRs and NLRP3 together with the adaptor ASC protein PYCARD forms a caspase-1 activating complex known as the NLRP3 inflammasome. NLRP3 in the absence of activating signal is kept in an inactive state complexed with HSP90 and SGT1 in the cytoplasm. NLRP3 inflammasome detects danger signals such as crystalline uric acid and extracellular ATP released by damaged cells. These signals release HSP90 and SGT1 from and recruit ASC protein and caspase-1 to the inflammasome complex. Caspase-1 within the activated NLRP3 inflammasome complex in turn activates the inflammatory cytokine, IL-1β. The NLRP3 inflammasome appears to be activated by changes in intracellular potassium caused by potassium efflux from mechanosensitive ion channels located in the cell membrane. It appears that NLRP3 is also regulated by reactive oxygen species (ROS), though the precise mechanisms of such regulation has not been determined. Here you can see a cryoEM structure of the human NLRP3 open octamer (PDB code: 8SWF)

#molecularart ... #inflammasome ... #NLRP3 ... #receptor ... #autoinmune ... #cryoem

Structure rendered with @proteinimaging and depicted with @corelphotopaint