Structural Control of <scp>NLRP3</scp> Inflammasome Assembly and the Emerging Microprotein Frontier

Abstract

The NLRP3 inflammasome responds to chemically and biologically diverse stimuli, yet growing evidence indicates that this apparent diversity converges on a limited set of structural and spatial licensing steps. Here, we argue that NLRP3 regulation is best understood through an assembly-centered framework rather than as another stimulus-centered catalog of activators. Cryo-electron microscopy (Cryo-EM), biochemical, and cell-biological studies support a model in which NLRP3 is maintained in inactive cage-like assemblies, undergoes nucleotide-dependent conformational rearrangements, engages NEK7, and nucleates ordered supramolecular complexes containing apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC). We synthesize current evidence for structural licensing, interface-level restraint, subcellular trafficking, phase-separation-linked organization, and post-translational and proteostatic control of NLRP3 assembly. We then examine a less explored question with translational implications: whether peptide-scale regulators, particularly endogenous microproteins, may control defined assembly transitions. Available evidence supports the existence of synthetic peptides that inhibit inflammasome interfaces and of endogenous microproteins that intersect with inflammatory signaling. However, direct evidence that endogenous microproteins act as dedicated interface-mimic inhibitors of NLRP3 assembly remains lacking. This review integrates mature structural models of NLRP3 regulation with the emerging microprotein field while clearly distinguishing established mechanisms from plausible but unproven hypotheses. This perspective defines a mechanistically explicit agenda for future work, including rigorous validation of translated small open reading frames (smORFs), direct interaction mapping to defined NLRP3 surfaces, and quantitative testing of effects on assembly, signaling output, and cellular context.