Gasdermin D (GSDMD) is the common effector for cytokine secretion and pyroptosis downstream of inflammasome activation and was previously shown to form large transmembrane pores upon cleavage by inflammatory caspases to generate the GSDMD N-terminal domain (GSDMD-NT)^1-10. Here we report that GSDMD Cys191 is S-palmitoylated and palmitoylation is required for pore formation. S-palmitoylation, which does not affect GSDMD cleavage, is augmented by mitochondria-generated reactive oxygen species (ROS). Surprisingly, cleavage-deficient D275A GSDMD is also palmitoylated after inflammasome stimulation or treatment with ROS activators, and causes pyroptosis, although less efficiently than palmitoylated GSDMD-NT. Palmitoylated, but not unpalmitoylated, full-length GSDMD induces liposome leakage, and forms a pore similar in structure to GSDMD-NT pores shown by cryogenic electron microscopy. zDHHC5 and zDHHC9 are the major palmitoyltransferases that mediate GSDMD palmitoylation, and their expression is upregulated by inflammasome activation and ROS. The other human gasdermins are also palmitoylated in their N-termini. These data challenge the concept that cleavage is the only trigger for GSDMD activation. They suggest that reversible palmitoylation is a checkpoint for pore formation by both GSDMD-NT and intact GSDMD that serves as a general switch for the activation of this pore-forming family.

Gasdermin D (GSDMD) 是炎症小体激活下游细胞因子分泌和细胞焦亡的常见效应子，之前已被证明在被炎症半胱天冬酶裂解后形成大的跨膜孔，生成 GSDMD N 末端结构域 (GSDMD-NT) ^1-10。在这里，我们报告 GSDMD Cys191 是 S-棕榈酰化的，并且棕榈酰化是孔形成所必需的。 S-棕榈酰化不会影响 GSDMD 裂解，但会被线粒体产生的活性氧 (ROS) 增强。令人惊讶的是，裂解缺陷的 D275A GSDMD 在炎症小体刺激或 ROS 激活剂处理后也会被棕榈酰化，并导致细胞焦亡，尽管效率低于棕榈酰化 GSDMD-NT。棕榈酰化（而非非棕榈酰化）全长 GSDMD 会诱导脂质体渗漏，并形成与低温电子显微镜显示的 GSDMD-NT 孔结构相似的孔。 zDHHC5 和 zDHHC9 是介导 GSDMD 棕榈酰化的主要棕榈酰转移酶，其表达通过炎症小体激活和 ROS 上调。其他人类 Gasdermin 的 N 末端也被棕榈酰化。这些数据挑战了裂解是 GSDMD 激活的唯一触发因素的概念。他们认为，可逆棕榈酰化是 GSDMD-NT 和完整 GSDMD 成孔的检查点，是激活该成孔家族的通用开关。