Nicotinamide adenine dinucleotide (NAD⁺) kinase (NADK) phosphorylates NAD⁺ to generate NADP⁺, which plays a crucial role in maintaining NAD⁺/NADP⁺ homeostasis, cellular redox balance, and metabolism. However, how human NADK activity is regulated, and how dysregulation or mutation of NADK is linked to human diseases, such as cancers, are still not fully understood. Here, we present a cryo-EM structure of human tetrameric NADK and elaborate on the necessity of the NADK tetramer for its activity. The N-terminal region of human NADK, which does not exist in bacterial NADKs, modulates tetramer conformation, thereby regulating its activity. A methylation-deficient mutant, R45H, within the N-terminal region results in increased NADK activity and confers cancer chemotherapy resistance. Conversely, mutations in NADK identified among cancer patients alter the tetramer conformation, resulting in NADK inactivation and increasing the sensitivity of lung cancer cells to chemotherapy. Our findings partially unveil the structural basis for NADK regulation, offering insights into the cancer etiology of patients carrying NADK mutations.

NLRP3 inflammasome, an intracellular multiprotein complex, can be activated by a range of pathogenic microbes or endogenous hazardous chemicals. Its activation results in the release of cytokines such as IL-1β and IL-18, as well as Gasdermin D which eventually causes pyroptosis. The activation of NLRP3 inflammasome is under strict control and regulation by numerous pathways and mechanisms. Its excessive activation can lead to a persistent inflammatory response, which is linked to the onset and progression of severe illnesses. Recent studies have revealed that the subcellular localization of NLRP3 changes significantly during the activation process. In this review, we review the current understanding of the molecular mechanism of NLRP3 inflammasome activation, focusing on the subcellular localization of NLRP3 and the associated regulatory mechanisms. We aim to provide a comprehensive understanding of the dynamic transportation, activation, and degradation processes of NLRP3.