Immunity：邵峰院士团队揭开颗粒酶A精准靶向切割GSDMB以引发细胞焦亡的机制

Core Viewpoint - The research reveals the molecular mechanism by which Granzyme A (GZMA) activates Gasdermin B (GSDMB) through a unique dimeric structure, providing insights into lymphocyte pyroptotic killing and potential new avenues for cancer immunotherapy [2][12]. Group 1: Mechanism of Action - GZMA utilizes its dimeric structure to precisely cut and activate GSDMB, leading to pyroptotic cell death, which is crucial for immune responses against infections and tumors [5][12]. - The study identifies that GZMA's dimeric form has two exosites that bind to the C-terminal domain of GSDMB, ensuring accurate cleavage at the Lys244 site, which is essential for GSDMB's activation [7][9]. Group 2: Structural Insights - The dimerization of GZMA is critical for its function, as disrupting this structure impairs its ability to bind and activate GSDMB, while not affecting its ability to cleave other substrates [7][9]. - The precise positioning of the cleavage site at Lys244 is facilitated by the cooperative action of the two GZMA monomers, highlighting the importance of structural integrity for enzymatic function [9]. Group 3: Evolutionary Differences - GSDMB is present in humans but absent in mice, although mouse GZMA can still cleave human GSDMB with reduced efficiency due to differences in key amino acids at the exosite [11]. - The research team engineered a mutant form of mouse GZMA that significantly improved its efficiency in cleaving GSDMB, providing a new tool for studying GZMA-GSDMB pathways in mouse models [11]. Group 4: Implications for Immunotherapy - The findings suggest that enhancing GSDMB-dependent pyroptosis could improve the efficacy of immune cells against tumors, opening new therapeutic strategies in cancer immunotherapy [12]. - The mechanism may also offer new targets for diseases associated with GSDMB, such as asthma and inflammatory bowel disease, indicating broader implications for immune modulation [12].