Insights into gasdermin pore formation from the structure of a pre‐pore

Downstream of inflammasome activation, gasdermin D (GSDMD) mediates IL‐1β secretion and pyroptosis by forming membrane pores. Structural investigation into GSDMD pore formation will provide new mechanistic knowledge about the GSDM family and facilitate the treatment of GSDMD‐associated diseases. We hypothesize a dynamic model where upon caspase cleavage of autoinhibited GSDMD, GSDMD‐NTs dissociate from GSDMD‐CTs for lipid binding and oligomerization into a pre‐pore, followed by β‐barrel insertion to form a membrane pore. In light of our recently resolved structure of the mouse GSDMA3 membrane pore, we aim to determine the structure of a GSDM pre‐pore. We arrest the pore formation process at the pre‐pore stage by generating a GSDMA3 mutant defective in membrane insertion while functional in lipid binding and oligomerization. Cryo‐electron microscopy (Cryo‐EM) analysis reveals a pre‐pore conformation where GSDMA3‐NT subunits oligomerize into a soluble ring without extended transmembrane β strands. Support or Funding Information This work was supported by US NIH grant DP1HD087988 (H.W.), R01Al124491 (H.W.), and Charles A. King Trust Postdoctoral Fellowship Program (J.R.). We thank the University of Massachusetts Cryo‐EM Core Facility and NCI National Cryo‐EM Facility for data collection. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .