Structure insight of GSDMD reveals the basis of GSDMD autoinhibition in cell pyroptosis

Abstract

Recent findings have revealed that the protein gasdermin D (GSDMD) plays key roles in cell pyroptosis. GSDMD binds lipids and forms pore structures to induce pyroptosis upon microbial infection and associated danger signals. However, detailed structural information for GSDMD remains unknown. Here, we report the crystal structure of the C-terminal domain of human GSDMD (GSDMD-C) at 2.64-Å resolution. The first loop on GSDMD-C inserts into the N-terminal domain (GSDMD-N), which helps stabilize the conformation of the full-length GSDMD. Substitution of this region by a short linker sequence increased levels of cell death. Mutants F283A and F283R can increase protein heterogeneity in vitro and are capable of undergoing cell pyroptosis in 293T cells. The small-angle X-ray-scattering envelope of human GSDMD is consistent with the modeled GSDMD structure and mouse GSDMA3 structure, which suggests that GSDMD adopts an autoinhibited conformation in solution. The positive potential surface of GSDMD-N covered by GSDMD-C is exposed after being released from the autoinhibition state and can form high-order oligomers via a charge-charge interaction. Furthermore, by mapping different regions of GSDMD, we determined that one short segment is sufficient to kill bacteria in vitro and can efficiently inhibit cell growth in and These findings reveal that GSDMD-C acts as an auto-inhibition executor and GSDMD-N could form pore structures via a charge-charge interaction upon cleavage by caspases during cell pyroptosis.

Gasdermins and their role in immunity and inflammation

“…In 2018, the crystal structure of the mouse GSDMA3 pore was solved (Ruan et al, 2018), providing critical insight into GSDM pore formation. Although the C-terminal domain of GSDMD, as well as the full-length GSDMA3, had previously been solved (Ding et al, 2016; Kuang et al, 2017; Liu et al, 2018) and later the full-length mouse and human GSDMD (Liu et al, 2019), this was the first crystal structure giving insights into the molecular basis of pore formation. It revealed that GSDMA forms pores consisting of 27–28 protomers with an internal diameter of ∼180 Å.…”

Urate‐induced immune programming: Consequences for gouty arthritis and hyperuricemia

“…68 Pyroptosis is a type of inflammatory cell death mediated by gasdermin D (GSDMD) processing to release N-terminal GSDMD fragment which, subsequently, contributes to pore structure formation at the plasma membrane. 69,70 This results in the release into the extracellular milieu of DAMPs such as DNA, ATP, ASC oligomers, or intracellular cytokines that further recruit immune cells and perpetuate the inflammatory response and tissue damage. 71,72 MSU crystal-induced activation of GSDMD has been recently described ( Figure 2).…”

Mechanism and Regulation of Gasdermin-Mediated Cell Death

“…In the autoinhibited state, GSDM-CT folds back onto GSDM-NT to repress its activity. The basis for this autoinhibitory mechanism was elucidated by the X-ray crystal structures of full-length (FL) mouse GSDMA3 as well as both human and mouse GSDMD (Ding et al 2016;Kuang et al 2017;Liu et al 2018Liu et al , 2019. GSDM-NT contains both α-helices and extended β-strands, whereas GSDM-CT is almost exclusively α-helical.…”