USP13 stabilizes NLRP3 to facilitate inflammasome activation by preventing TRIM31-mediated NLRP3 ubiquitination and degradation.

NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) has a fundamental role in host defense and is involved in diverse inflammatory diseases. NLRP3 protein expression is tightly controlled by the ubiquitin system. In particular, NLRP3 protein degradation has been extensively studied. In contrast, the mechanisms to stabilize NLRP3 protein are much less known. Here, we demonstrated the critical role of ubiquitin-specific protease 13 (USP13) in regulating NLRP3 protein stability and inflammasome activation independently of its deubiquitinating enzyme activity. USP13 competes with E3 ubiquitin ligase TRIM31 to interact with NLRP3 and prevents TRIM31-mediated NLRP3 ubiquitination at K192 and K496 sites, thereby inhibiting proteasomal degradation of NLRP3. USP13 deficiency reduces NLRP3 protein expression in both human and mouse macrophages, which consequently inhibits NLRP3 inflammasome assembly and activation. Accordingly, deficiency of USP13 attenuates monosodium urate crystal-induced mouse peritonitis. Overall, our findings reveal a previously unrecognized regulatory mechanism of NLRP3 stability by USP13 and provide a potential therapeutic target for NLRP3-driven diseases.