Peptide binding at the gasdermin D exosite reveals the structural basis for targeting the site

What is it about?

Gasdermin D (GSDMD) is a central effector of the inflammasome pathway, where its caspase-mediated cleavage triggers pore formation and pyroptotic cell death. Dysregulated GSDMD activity has been implicated in a broad range of inflammatory and autoimmune diseases, underscoring its therapeutic relevance. This article reports the first crystal structure of GSDMD bound to a rationally designed peptide ligand, identified through a structure-based computational screening approach. The structure reveals peptide engagement at a previously underexplored exosite, distinct from the catalytic cleavage site. Complementary biochemical assays demonstrate that this interaction may inhibit caspase-dependent cleavage of GSDMD, validating the functional relevance of exosite targeting.

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Photo by Nigel Hoare on Unsplash

Photo by Nigel Hoare on Unsplash

Why is it important?

To date, most reported GSDMD inhibitors rely on covalent modification of cysteine residues, which can limit selectivity and raise concerns regarding off-target reactivity. In contrast, this work establishes a non-covalent, structure-guided strategy for modulating GSDMD activity. By mimicking the caspase-1 substrate recognition motif, cyclic peptides were identified that recapitulate key features of the caspase hairpin loop and engage the GSDMD exosite. This approach effectively blocks access to the cleavage interface, thereby preventing activation without directly targeting catalytic residues. The resulting structural and biochemical framework provides a foundation for iterative design of next-generation exosite-targeted inhibitors, including constrained peptides and small molecules