The Lysosomal Rag-Ragulator Complex Licenses RIPK1 and Caspase-8-mediated Pyroptosis by <i>Yersinia</i>.

Abstract

Host cells initiate cell death programs to limit pathogen infection. Inhibition of transforming growth factor-β-activated kinase 1 (TAK1) by pathogenic <i>Yersinia</i> in macrophages triggers receptor-interacting serine/threonine-protein kinase 1 (RIPK1)-dependent caspase-8 cleavage of gasdermin D (GSDMD) and inflammatory cell death (pyroptosis). A genome-wide clustered regularly interspaced short palindromic repeats (CRISPR) screen to uncover mediators of caspase-8-dependent pyroptosis identified an unexpected role of the lysosomal FLCN-FNIP2-Rag-Ragulator supercomplex, which regulates metabolic signalling and the mechanistic target of rapamycin complex 1 (mTORC1). In response to <i>Yersinia</i> infection, FADD, RIPK1 and caspase-8 were recruited to Rag-Ragulator, causing RIPK1 phosphorylation and caspase-8 activation. Pyroptosis activation depended on Rag GTPase activity and lysosomal tethering of Rag-Ragulator, but not mTORC1. Thus, the lysosomal metabolic regulator Rag-Ragulator instructs the inflammatory response to <i>Yersinia</i>.