Structural Insight of Gasdermin Family Driving Pyroptotic Cell Death

Gasdermin is a recently identified family of pore-forming proteins consisting of Gasdermin A (GSDMA), Gasdermin B (GSDMB), Gasdermin C (GSDMC), Gasdermin D (GSDMD), Gasdermin E (GSDME), and DFNB59. Gasdermin D (GSDMD) is a downstream effector of inflammasomes, which are supramolecular complexes that activate inflammatory caspases (-1, -4, and -5 in human and -1 and -11 in mouse). GSDMD contains a functionally important N-terminal domain (GSDMD-N), a C-terminal domain, and a linker in between that is recognized and cleaved by the activated inflammatory caspases. Upon cleavage, the GSDMD-N fragments translocate on the membrane and oligomerize to form membrane-embedded pores after specifically binding to acidic lipids such as phosphatidylinositol phosphates (PIPs), phosphatidic acid (PA), phosphatidylserine (PS), and cardiolipin. The pore exhibits strong membrane-disrupting cytotoxicity in mammalian cells by disrupting the osmotic potential and also serves as a gate for extracellular release of mature IL-1β and IL-18 during pyroptosis. In this chapter, we review our current understanding of GSDM proteins in physiological and pathological cell death, with more focused discussions on its structural basis for GSDM activation and pore formation.