The study investigates the mechanism by which gasdermin D (GSDMD) triggers pyroptosis, an inflammatory form of cell death. When activated by inflammatory caspases, GSDMD is cleaved to form the N-terminal fragment (GSDMD-NT), which oligomerizes in membranes to form pores. These pores are visible under electron microscopy and bind to phosphatidylinositol phosphates, phosphatidylserine, and cardiolipin. Mutations in four conserved basic residues block GSDMD-NT oligomerization, membrane binding, pore formation, and pyroptosis. GSDMD-NT oligomerizes in the plasma membrane and kills cells from within, without harming neighboring cells. It also kills free bacteria in vitro and may have a direct bactericidal effect within host cells. The study confirms that GSDMD-NT forms pores that permeabilize mammalian membranes during pyroptosis, and that these pores are selective for lipids present on the inner leaflet of the plasma membrane. The findings suggest that GSDMD-NT's selective activity helps control tissue damage and limits the spread of infection.The study investigates the mechanism by which gasdermin D (GSDMD) triggers pyroptosis, an inflammatory form of cell death. When activated by inflammatory caspases, GSDMD is cleaved to form the N-terminal fragment (GSDMD-NT), which oligomerizes in membranes to form pores. These pores are visible under electron microscopy and bind to phosphatidylinositol phosphates, phosphatidylserine, and cardiolipin. Mutations in four conserved basic residues block GSDMD-NT oligomerization, membrane binding, pore formation, and pyroptosis. GSDMD-NT oligomerizes in the plasma membrane and kills cells from within, without harming neighboring cells. It also kills free bacteria in vitro and may have a direct bactericidal effect within host cells. The study confirms that GSDMD-NT forms pores that permeabilize mammalian membranes during pyroptosis, and that these pores are selective for lipids present on the inner leaflet of the plasma membrane. The findings suggest that GSDMD-NT's selective activity helps control tissue damage and limits the spread of infection.