Structural basis and regulation of GSDME pore formation

Area of Science:

• Biochemistry
• Structural Biology
• Cell Biology

Background:

• Gasdermins (GSDMs) are crucial pore-forming proteins involved in pyroptosis, inflammation, and cancer.
• The precise mechanisms of GSDME activation and pore assembly are not fully understood.

Purpose of the Study:

• To elucidate the high-resolution structures of human GSDME pores.
• To identify the molecular determinants of GSDME activation and pore formation.

Main Methods:

• Cryo-electron microscopy (cryo-EM) to determine GSDME pore structures.
• Structure-guided mutagenesis to investigate protein-lipid and protein-protein interactions.
• Biochemical assays to assess GSDME activation and function.

Main Results:

• Determined high-resolution cryo-EM structures of 27- and 28-fold human GSDME pores.
• Identified conserved structural features and distinct membrane-engagement geometry.
• Discovered that caspase-3 cleaves GSDME at a DMPD motif, and S-palmitoylation enhances pore formation via Cys180.

Conclusions:

• GSDME pore formation is regulated by a sequential process involving proteolytic activation and lipid modification.
• These findings provide a framework for understanding GSDME function in inflammatory and cancer-related processes.