Inflammasome adaptor protein ASC is a mechanistic checkpoint in IL-1β maturation

• 成果类型: Article
• 署名作者: Saha, Giti; Anchi, Pratibha; Wang, Richard; Biondo, Alyssa; Meyer, Sadie; Kondragunta, Vinata; Luchsinger, Larry L.; Syed, Ismail; Sharif, Humayun; Wu, Hao; Giri Magupalli, Venkat
• 署名单位: New York Blood Center; New York Blood Center; Harvard University; Harvard University Medical Affiliates; Beth Israel Deaconess Medical Center; Harvard University; Harvard Medical School; Khalifa University of Science & Technology; Harvard University; Harvard Medical School; Harvard University; Harvard University Medical Affiliates; Boston Children's Hospital; Program in Cellular & Molecular Medicine (PCMM)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.2537563123
• 发表日期: 2026-05-12
• 页码: e2537563123
• 关键词: inflammasomes; IL-1 beta; pyroptosis; GASDERMIN-D; cell-death; activation; nlrp3; membrane; caspases

摘要

Inflammasome activation triggers caspase-1-dependent maturation of pro-interleukin-1 beta (pro-IL-1 beta) in an apoptosis-associated speck-like protein containing a CARD (ASC)-dependent manner, yet the mechanism by which pro-IL-1 beta is physically recruited to the ASC signaling platform has remained undefined. Here, we identify the ASC linker domain (ASCLD) as a noncanonical protein-interaction interface, that can directly recruits pro-IL-1 beta onto the ASC speck. Using a live-cell NanoBRET assay, confocal imaging, and pulldown analysis, we show that ASC directly engages pro-IL-1 beta and that this interaction requires a discrete set of charged residues in the IL-1 beta mature domain region, forming an ASC-docking surface. Mutagenesis guided by the IL-1 beta structure confirmed that this interaction is essential for caspase-1-dependent IL-1 beta maturation but dispensable for pyroptosis. Domain mapping revealed that ASCLD, rather than its N-terminal Pyrin domain (PYD) or C-terminal caspase recruitment domain (CARD), mediates pro-IL-1 beta recruitment. Using an in-house custom antibody against ASCLD, we show that this region remains exposed within endogenous ASC specks in macrophages. Mutational disruption of ASCLD selectively impaired IL-1 beta processing in THP-1 cells Mutations disruption data was obtained from THP-1 cells without affecting ASC speck formation or pyroptosis. A cell-penetrating peptide derived from ASCLD selectively blocked pro-IL-1 beta docking while preserving speck assembly. In 2 mouse models of peritonitis, the blocking peptide uncoupled cytokine maturation from pyroptosis and significantly reduced IL-1 beta-driven inflammation. Thus, our findings uncover ASCLD as a critical docking interface that positions pro-IL-1 beta for efficient caspase-1 processing, which adds a mechanistic checkpoint within inflammasomes to license cytokine maturation independently of pyroptotic death. We propose that ASCLD may be a therapeutically tractable node for selective modulation of IL-1 beta-driven inflammasomopathies.