The study investigates the structural basis for the oligomerization-facilitated activation of the NACHT-, leucine-rich-repeat-, and pyrin domain-containing protein 3 (NLRP3), a critical intracellular inflammasome sensor. Using cryo-electron microscopy, the researchers determined the structure of an open octamer of NLRP3, which undergoes a ~90° hinge rotation at the NACHT domain. Mutations at the interfaces of the open octamer reduce IL-1β signaling, highlighting their essential role in NLRP3 activation and inflammasome assembly. The centrosomal NIMA-related kinase 7 (NEK7) disrupts large NLRP3 oligomers and forms NEK7/NLRP3 monomers/dimers, a critical step before the assembly of the disk-like inflammasome. These findings provide insights into the cooperative activation mechanism of NLRP3 and its inflammasome assembly. The study also explores the impact of oligomerization on NLRP3 activation and ASC speck formation, and demonstrates that NEK7 dissociates NLRP3 oligomers into NEK7/NLRP3 dimers. The proposed activation mechanism involves a two-step process: priming, which triggers NLRP3 transcriptional upregulation and oligomerization forming closed cages, followed by ATP-induced conformational changes and oligomer reorganization to form an open octamer. The open octamer exposes a large catalytic surface for inflammasome assembly, and NEK7 engagement can dissociate the octamer into NEK7/NLRP3 binary complexes, allowing uni- or bi-directional inflammasome assembly.The study investigates the structural basis for the oligomerization-facilitated activation of the NACHT-, leucine-rich-repeat-, and pyrin domain-containing protein 3 (NLRP3), a critical intracellular inflammasome sensor. Using cryo-electron microscopy, the researchers determined the structure of an open octamer of NLRP3, which undergoes a ~90° hinge rotation at the NACHT domain. Mutations at the interfaces of the open octamer reduce IL-1β signaling, highlighting their essential role in NLRP3 activation and inflammasome assembly. The centrosomal NIMA-related kinase 7 (NEK7) disrupts large NLRP3 oligomers and forms NEK7/NLRP3 monomers/dimers, a critical step before the assembly of the disk-like inflammasome. These findings provide insights into the cooperative activation mechanism of NLRP3 and its inflammasome assembly. The study also explores the impact of oligomerization on NLRP3 activation and ASC speck formation, and demonstrates that NEK7 dissociates NLRP3 oligomers into NEK7/NLRP3 dimers. The proposed activation mechanism involves a two-step process: priming, which triggers NLRP3 transcriptional upregulation and oligomerization forming closed cages, followed by ATP-induced conformational changes and oligomer reorganization to form an open octamer. The open octamer exposes a large catalytic surface for inflammasome assembly, and NEK7 engagement can dissociate the octamer into NEK7/NLRP3 binary complexes, allowing uni- or bi-directional inflammasome assembly.