Downstream of gasdermin D cleavage, a Ragulator-Rag-mTORC1 pathway promotes pore formation and pyroptosis
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 are recognized to promote GSDMD cleavage, but none are known to be required for pore formation after GSDMD cleavage. Herein, we report a forward genetic screen that was designed to identify regulators of pyroptosis that act downstream of GSDMD cleavage. This screen identified several components of the Ragulator-Rag complex, which is known for its metabolic control of mTOR. Mechanistic studies revealed that Ragulator-Rag is not necessary for GSDMD localization to the plasma membrane, but is necessary for pore formation and mitochondrial inactivation. Downstream of Ragulator-Rag is mTORC1, which we found to promote pyroptosis in response to diverse natural stimuli, including infection. GSDMD therefore requires a Ragulator-Rag-mTORC1 pathway in order to form pores and execute pyroptosis.