cyclic-guanosine-monophosphate-adenosine-monophosphate and Niemann-Pick-Disease--Type-C

The classic mode of STING activation is through binding the cyclic dinucleotide 2'3'-cyclic GMP-AMP (cGAMP), produced by the DNA sensor cyclic GMP-AMP synthase (cGAS), which is important for the innate immune response to microbial infection and autoimmune disease. Modes of STING activation that are independent of cGAS are much less well understood. Here, through a spatiotemporally resolved proximity labelling screen followed by quantitative proteomics, we identify the lysosomal membrane protein Niemann-Pick type C1 (NPC1) as a cofactor in the trafficking of STING. NPC1 interacts with STING and recruits it to the lysosome for degradation in both human and mouse cells. Notably, we find that knockout of Npc1 'primes' STING signalling by physically linking or 'tethering' STING to SREBP2 trafficking. Loss of NPC1 protein also 'boosts' STING signalling by blocking lysosomal degradation. Both priming and boosting of STING signalling are required for severe neurological disease in the Npc1

Topics: Animals; Cell Line; Cerebellum; Endoplasmic Reticulum; Golgi Apparatus; Humans; Interferon Regulatory Factor-3; Interferon Type I; Lysosomes; Membrane Proteins; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Microglia; Models, Biological; Motor Skills; Neuroinflammatory Diseases; Niemann-Pick C1 Protein; Niemann-Pick Disease, Type C; Nucleotides, Cyclic; Nucleotidyltransferases; Protein Serine-Threonine Kinases; Protein Transport; Proteolysis; Purkinje Cells; Signal Transduction; Sterol Regulatory Element Binding Protein 2