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Full-Text Articles in Hemic and Immune Systems
Control Of Antiviral Innate Immune Response By Protein Geranylgeranylation, Shigao Yang, Zhaozhao Jiang, Katherine A. Fitzgerald, Donghai Wang
Control Of Antiviral Innate Immune Response By Protein Geranylgeranylation, Shigao Yang, Zhaozhao Jiang, Katherine A. Fitzgerald, Donghai Wang
Katherine A. Fitzgerald
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 …
Constitutive Interferon Signaling Maintains Critical Threshold Of Mlkl Expression To License Necroptosis, Joseph Sarhan, Beiyun C. Liu, Hayley I. Muendlein, Chi G. Weindel, Irina Smirnova, Amy Y. Tang, Vladimir Ilyukha, Maxim Sorokin, Anton Buzdin, Katherine A. Fitzgerald, Alexander Poltorak
Constitutive Interferon Signaling Maintains Critical Threshold Of Mlkl Expression To License Necroptosis, Joseph Sarhan, Beiyun C. Liu, Hayley I. Muendlein, Chi G. Weindel, Irina Smirnova, Amy Y. Tang, Vladimir Ilyukha, Maxim Sorokin, Anton Buzdin, Katherine A. Fitzgerald, Alexander Poltorak
Katherine A. Fitzgerald
Interferons (IFNs) are critical determinants in immune-competence and autoimmunity, and are endogenously regulated by a low-level constitutive feedback loop. However, little is known about the functions and origins of constitutive IFN. Recently, lipopolysaccharide (LPS)-induced IFN was implicated as a driver of necroptosis, a necrotic form of cell death downstream of receptor-interacting protein (RIP) kinase activation and executed by mixed lineage kinase like-domain (MLKL) protein. We found that the pre-established IFN status of the cell, instead of LPS-induced IFN, is critical for the early initiation of necroptosis in macrophages. This pre-established IFN signature stems from cytosolic DNA sensing via cGAS/STING, and …