Browsing by Author "Miao, David"

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    Control of antiviral innate immune response by protein geranylgeranylation
    (Science Advances, 2019-05) Yang, Shigao; Harding, Alfred T; Sweeney, Catherine; Miao, David; Swan, Gregory; Zhou, Connie; Jiang, Zhaozhao; Fitzgerald, Katherine A; Hammer, Gianna; Bergo, Martin O; Kroh, Heather K; Lacy, D Borden; Sun, Chunxiang; Glogauer, Michael; Que, Loretta G; Heaton, Nicholas S; Wang, Donghai
    The mitochondrial antiviral signaling protein (MAVS) orchestrates host antiviral innate immune response to RNA virus infection. However, how MAVS signaling is controlled to eradicate virus while preventing self-destructive inflammation remains obscure. Here, we show that protein geranylgeranylation, a posttranslational lipid modification of proteins, limits MAVS-mediated immune signaling by targeting Rho family small guanosine triphosphatase Rac1 into the mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) at the mitochondria-ER junction. Protein geranylgeranylation and subsequent palmitoylation promote Rac1 translocation into MAMs upon viral infection. MAM-localized Rac1 limits MAVS’ interaction with E3 ligase Trim31 and hence inhibits MAVS ubiquitination, aggregation, and activation. Rac1 also facilitates the recruitment of caspase-8 and cFLIPL to the MAVS signalosome and the subsequent cleavage of Ripk1 that terminates MAVS signaling. Consistently, mice with myeloid deficiency of protein geranylgeranylation showed improved survival upon influenza A virus infection. Our work revealed a critical role of protein geranylgeranylation in regulating antiviral innate immune response.
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    Control of the innate immune response by the mevalonate pathway.
    (Nat Immunol, 2016-08) Akula, Murali K; Shi, Man; Jiang, Zhaozhao; Foster, Celia E; Miao, David; Li, Annie S; Zhang, Xiaoman; Gavin, Ruth M; Forde, Sorcha D; Germain, Gail; Carpenter, Susan; Rosadini, Charles V; Gritsman, Kira; Chae, Jae Jin; Hampton, Randolph; Silverman, Neal; Gravallese, Ellen M; Kagan, Jonathan C; Fitzgerald, Katherine A; Kastner, Daniel L; Golenbock, Douglas T; Bergo, Martin O; Wang, Donghai
    Deficiency in mevalonate kinase (MVK) causes systemic inflammation. However, the molecular mechanisms linking the mevalonate pathway to inflammation remain obscure. Geranylgeranyl pyrophosphate, a non-sterol intermediate of the mevalonate pathway, is the substrate for protein geranylgeranylation, a protein post-translational modification that is catalyzed by protein geranylgeranyl transferase I (GGTase I). Pyrin is an innate immune sensor that forms an active inflammasome in response to bacterial toxins. Mutations in MEFV (encoding human PYRIN) result in autoinflammatory familial Mediterranean fever syndrome. We found that protein geranylgeranylation enabled Toll-like receptor (TLR)-induced activation of phosphatidylinositol-3-OH kinase (PI(3)K) by promoting the interaction between the small GTPase Kras and the PI(3)K catalytic subunit p110δ. Macrophages that were deficient in GGTase I or p110δ exhibited constitutive release of interleukin 1β that was dependent on MEFV but independent of the NLRP3, AIM2 and NLRC4 inflammasomes. In the absence of protein geranylgeranylation, compromised PI(3)K activity allows an unchecked TLR-induced inflammatory responses and constitutive activation of the Pyrin inflammasome.