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

Gasdermin D (GSDMD) has been identified as a critical component of the inflammasome, an important intracellular signaling multi-protein complex. Abnormal activation of GSDMD has been linked to a variety of inflammatory diseases, including non-alcoholic steatohepatitis, inflammatory bowel disease and COVID-19, and has been linked to potential pathogenesis of septic shock. While small molecules have been identified to inhibit N-terminal domain (NTD) pore formation and membrane translocation, further clinical application of these molecules is currently limited due to narrow specificity. Here, we report a peptide from a structure-based computational screen that selectively inhibits caspase-dependent cleavage of GSDMD. We have determined the structure of the GSDMD-peptide complex, indicating that peptide binding is facilitated by negatively charged residues from the peptide and the hydrophobic exosite of the protein, inhibiting caspase binding and activation. The experimental data suggest the potential to target the exosite for therapeutic intervention.