ROS-dependent palmitoylation is an obligate licensing modification for GSDMD pore formation

Area of Science:

• Cellular Biology
• Immunology
• Biochemistry

Background:

• Gasdermin D (GSDMD) is a key mediator of pyroptosis and inflammatory cytokine release.
• GSDMD forms transmembrane pores upon cleavage by inflammatory caspases, but the precise activation mechanism remains unclear.

Approach:

• Investigated the role of post-translational modifications in GSDMD activation.
• Utilized palmitoylation inhibitors, site-directed mutagenesis, and ROS manipulation to assess GSDMD function.
• Employed liposome leakage assays to quantify GSDMD pore-forming activity.

Key Points:

• GSDMD requires S-palmitoylation at Cys191 for N-terminal domain (GSDMD-NT) membrane translocation and pore formation, independent of its cleavage.
• Reactive oxygen species (ROS) levels directly correlate with and regulate GSDMD palmitoylation.
• zDHHC5 and zDHHC9 were identified as the primary palmitoyl transferases for GSDMD.

Conclusions:

• Palmitoylation acts as a crucial licensing step for GSDMD-mediated pyroptosis.
• ROS-induced palmitoylation is a critical switch for GSDMD activation and inflammatory cell death.
• This mechanism may be conserved across the GSDM family, suggesting a general regulatory pathway for pyroptosis.