Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
Division of Gastroenterology, Boston Children's Hospital and Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia; EN-FIST Centre of Excellence, Trg Osvobodilne fronte 13, 1000 Ljubljana, Slovenia.
Cell. 2021 Aug 19;184(17):4495-4511.e19. doi: 10.1016/j.cell.2021.06.028. Epub 2021 Jul 21.
The process of pyroptosis is mediated by inflammasomes and a downstream effector known as gasdermin D (GSDMD). Upon cleavage by inflammasome-associated caspases, the N-terminal domain of GSDMD forms membrane pores that promote cytolysis. Numerous proteins promote GSDMD cleavage, but none are known to be required for pore formation after GSDMD cleavage. Herein, we report a forward genetic screen that identified the Ragulator-Rag complex as being necessary for GSDMD pore formation and pyroptosis in macrophages. Mechanistic analysis revealed that Ragulator-Rag is not required for GSDMD cleavage upon inflammasome activation but rather promotes GSDMD oligomerization in the plasma membrane. Defects in GSDMD oligomerization and pore formation can be rescued by mitochondrial poisons that stimulate reactive oxygen species (ROS) production, and ROS modulation impacts the ability of inflammasome pathways to promote pore formation downstream of GSDMD cleavage. These findings reveal an unexpected link between key regulators of immunity (inflammasome-GSDMD) and metabolism (Ragulator-Rag).
细胞焦亡过程由炎性小体和一种称为 Gasdermin D (GSDMD) 的下游效应蛋白所介导。在炎性小体相关半胱天冬酶的切割作用下，GSDMD 的 N 端结构域形成促进细胞裂解的膜孔。许多蛋白促进 GSDMD 切割，但在 GSDMD 切割后，没有已知的蛋白是形成孔所必需的。在此，我们报告了一项正向遗传学筛选，该筛选确定 Ragulator-Rag 复合物是巨噬细胞中 GSDMD 孔形成和细胞焦亡所必需的。机制分析表明，Ragulator-Rag 在炎性小体激活时不需要 GSDMD 切割，但在质膜中促进 GSDMD 寡聚化。GSDMD 寡聚化和孔形成缺陷可被刺激活性氧 (ROS) 产生的线粒体毒物挽救，并且 ROS 调节会影响炎性小体途径在 GSDMD 切割下游促进孔形成的能力。这些发现揭示了免疫（炎性小体-GSDMD）和代谢（Ragulator-Rag）关键调节因子之间的意外联系。
