Nek7 is an essential mediator of NLRP3 inflammasome activation downstream of potassium efflux. This study identifies Nek7 as a binding protein that acts downstream of potassium efflux to regulate NLRP3 oligomerization and activation. Nek7 is required for NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NLRC4 or AIM2 inflammasomes. NLRP3-activating stimuli promote the NLRP3-Nek7 interaction, which is dependent on potassium efflux. Nek7 associates with the catalytic domain of NLRP3, but its catalytic activity is not required for NLRP3 inflammasome activation. Activated macrophages form a high-molecular-mass NLRP3-Nek7 complex, which is abrogated in the absence of Nek7. Nek7 is required for macrophages harboring the CAPS-associated NLRP3R258W activating mutation to activate caspase-1. Mouse chimeras reconstituted with wild-type, Nek7-/-, or Nlrp3-/- hematopoietic cells revealed that Nek7 was required for NLRP3 inflammasome activation in vivo. These studies demonstrate that Nek7 is an essential protein that acts downstream of potassium efflux to mediate NLRP3 inflammasome assembly and activation. Nek7 interacts with NLRP3 in a process dependent on potassium efflux. The NLRP3-Nek7 interaction is enhanced in response to NLRP3-activating stimuli. Nek7 is required for NLRP3 inflammasome activation in macrophages. Nek7 deficiency abrogates NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NLRC4 or AIM2 inflammasomes. Nek7 is required for NLRP3 inflammasome activation in vivo. Nek7 is essential for NLRP3 inflammasome activation downstream of potassium efflux. Nek7 is required for NLRP3 inflammasome activation in macrophages. Nek7 deficiency abrogates NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NLRC4 or AIM2 inflammasomes. Nek7 is required for NLRP3 inflammasome activation in vivo. Nek7 is essential for NLRP3 inflammasome activation downstream of potassium efflux. Nek7 is required for NLRP3 inflammasome activation in macrophages. Nek7 deficiency abrogates NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NLNek7 is an essential mediator of NLRP3 inflammasome activation downstream of potassium efflux. This study identifies Nek7 as a binding protein that acts downstream of potassium efflux to regulate NLRP3 oligomerization and activation. Nek7 is required for NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NLRC4 or AIM2 inflammasomes. NLRP3-activating stimuli promote the NLRP3-Nek7 interaction, which is dependent on potassium efflux. Nek7 associates with the catalytic domain of NLRP3, but its catalytic activity is not required for NLRP3 inflammasome activation. Activated macrophages form a high-molecular-mass NLRP3-Nek7 complex, which is abrogated in the absence of Nek7. Nek7 is required for macrophages harboring the CAPS-associated NLRP3R258W activating mutation to activate caspase-1. Mouse chimeras reconstituted with wild-type, Nek7-/-, or Nlrp3-/- hematopoietic cells revealed that Nek7 was required for NLRP3 inflammasome activation in vivo. These studies demonstrate that Nek7 is an essential protein that acts downstream of potassium efflux to mediate NLRP3 inflammasome assembly and activation. Nek7 interacts with NLRP3 in a process dependent on potassium efflux. The NLRP3-Nek7 interaction is enhanced in response to NLRP3-activating stimuli. Nek7 is required for NLRP3 inflammasome activation in macrophages. Nek7 deficiency abrogates NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NLRC4 or AIM2 inflammasomes. Nek7 is required for NLRP3 inflammasome activation in vivo. Nek7 is essential for NLRP3 inflammasome activation downstream of potassium efflux. Nek7 is required for NLRP3 inflammasome activation in macrophages. Nek7 deficiency abrogates NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NLRC4 or AIM2 inflammasomes. Nek7 is required for NLRP3 inflammasome activation in vivo. Nek7 is essential for NLRP3 inflammasome activation downstream of potassium efflux. Nek7 is required for NLRP3 inflammasome activation in macrophages. Nek7 deficiency abrogates NLRP3 inflammasome activation in response to NLRP3-activating stimuli, but not NL