Pyroptosis is a lytic cell death pathway usually triggered by infection that relies on the formation of gasdermin D (GSDMD) pores in the plasma membrane. How caspase-mediated cleavage of GSDMD, its insertion into the membrane and the subsequent oligomerization of the resulting N-terminal fragment (GSDMD-NT) are spatiotemporally regulated remains unclear. Now, Zhang et al. identify reversible S-palmitoylation of GSDMD as a crucial regulatory step of pyroptosis.

Previous studies had found a role for the GSDMD residue Cys192 (Cys191 in humans) in regulating GSDMD processing by caspase-1. Indeed, palmitoylation of Cys192 increased the interaction of GSDMD with caspase-1 in cells, leading to more efficient GSDMD processing. However, although overexpression of caspase-1 could rescue the decreased cleavage of GSDMD upon inhibition of palmitoylation, cell death rates remained reduced following 2-BP treatment in caspase-1-overexpressing cells. This finding implies a second function of Cys192 S-palmitoylation in pyroptosis that is independent of GSDMD–caspase complex formation. In line with this, cleaved GSDMD-NT retained its palmitoyl group following processing.