Browsing by Author "Quarato, Giovanni"

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    Caspase-8 and FADD prevent spontaneous ZBP1 expression and necroptosis
    (National Academy of Sciences, 2022) Rodriguez, Diego A.; Quarato, Giovanni; Liedmann, Swantje; Tummers, Bart; Zhang, Ting; Guy, Cliff; Crawford, Jeremy Chase; Palacios, Gustavo; Pelletier, Stephane; Kalkavan, Halime; Shaw, Jeremy J. P.; Fitzgerald, Patrick; Chen, Mark J.; Balachandran, Siddharth; Green, Douglas R.; Medical and Molecular Genetics, School of Medicine
    Caspase-8 and Fas-associated death domain (FADD) play key roles in the regulation of cell death by necroptosis. The absence of either protein results in early embryonic lethality due to the activation of the kinase receptor interacting protein kinase-3 (RIPK3) and its phosphorylation of the necroptosis executioner, mixed-lineage kinase-like (MLKL). We genetically engineered and characterized a mouse model to monitor MLKL phosphorylation in the absence of necroptosis in vivo. Ablation of caspase-8 or FADD resulted in the transcriptional upregulation in several tissues of Z-DNA binding protein-1 (ZBP1), a cytosolic nucleic acid sensor capable of activating RIPK3, and ZBP1 was required for spontaneous phosphorylation of MLKL. Our findings provide a mechanism by which the FADD/Caspase-8 complex prevents necroptosis.
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    The interaction between RIPK1 and FADD controls perinatal lethality and inflammation
    (Elsevier, 2024) Rodriguez, Diego A.; Tummers, Bart; Shaw, Jeremy J. P.; Quarato, Giovanni; Weinlich, Ricardo; Cripps, James; Fitzgerald, Patrick; Janke, Laura J.; Pelletier, Stephane; Crawford, Jeremy Chase; Green, Douglas R.; Medical and Molecular Genetics, School of Medicine
    Perturbation of the apoptosis and necroptosis pathways critically influences embryogenesis. Receptor-associated protein kinase-1 (RIPK1) interacts with Fas-associated via death domain (FADD)-caspase-8-cellular Flice-like inhibitory protein long (cFLIPL) to regulate both extrinsic apoptosis and necroptosis. Here, we describe Ripk1-mutant animals (Ripk1R588E [RE]) in which the interaction between FADD and RIPK1 is disrupted, leading to embryonic lethality. This lethality is not prevented by further removal of the kinase activity of Ripk1 (Ripk1R588E K45A [REKA]). Both Ripk1RE and Ripk1REKA animals survive to adulthood upon ablation of Ripk3. While embryonic lethality of Ripk1RE mice is prevented by ablation of the necroptosis effector mixed lineage kinase-like (MLKL), animals succumb to inflammation after birth. In contrast, Mlkl ablation does not prevent the death of Ripk1REKA embryos, but animals reach adulthood when both MLKL and caspase-8 are removed. Ablation of the nucleic acid sensor Zbp1 largely prevents lethality in both Ripk1RE and Ripk1REKA embryos. Thus, the RIPK1-FADD interaction prevents Z-DNA binding protein-1 (ZBP1)-induced, RIPK3-caspase-8-mediated embryonic lethality, affected by the kinase activity of RIPK1.