时尚
坏死性下垂
细胞生物学
半胱氨酸蛋白酶8
生物
死亡域
磷酸化
程序性细胞死亡
半胱氨酸蛋白酶
生物化学
细胞凋亡
作者
Diego A. Rodriguez,Giovanni Quarato,Swantje Liedmann,Bart Tummers,Ting Zhang,Cliff Guy,Jeremy Chase Crawford,Gustavo Palacios,Stephane Pelletier,Halime Kalkavan,Jeremy Joseph Porter Shaw,Patrick Fitzgerald,Mark J. Chen,Siddharth Balachandran,Douglas R. Green
标识
DOI:10.1073/pnas.2207240119
摘要
The absence of Caspase-8 or its adapter, Fas-associated death domain (FADD), results in activation of receptor interacting protein kinase-3 (RIPK3)- and mixed-lineage kinase-like (MLKL)–dependent necroptosis in vivo. Here, we show that spontaneous activation of RIPK3, phosphorylation of MLKL, and necroptosis in Caspase-8– or FADD-deficient cells was dependent on the nucleic acid sensor, Z-DNA binding protein-1 (ZBP1). We genetically engineered a mouse model by a single insertion of FLAG tag onto the N terminus of endogenous MLKL ( Mlkl FLAG/FLAG ), creating an inactive form of MLKL that permits monitoring of phosphorylated MLKL without activating necroptotic cell death. Casp8 −/− Mlkl FLAG/FLAG mice were viable and displayed phosphorylated MLKL in a variety of tissues, together with dramatically increased expression of ZBP1 compared to Casp8 +/+ mice. Studies in vitro revealed an increased expression of ZBP1 in cells lacking FADD or Caspase-8, which was suppressed by reconstitution of Caspase-8 or FADD. Ablation of ZBP1 in Casp8 −/− Mlkl FLAG/FLAG mice suppressed spontaneous MLKL phosphorylation in vivo. ZBP1 expression and downstream activation of RIPK3 and MLKL in cells lacking Caspase-8 or FADD relied on a positive feedback mechanism requiring the nucleic acid sensors cyclic GMP-AMP synthase (cGAS), stimulator of interferon genes (STING), and TBK1 signaling pathways. Our study identifies a molecular mechanism whereby Caspase-8 and FADD suppress spontaneous necroptotic cell death.
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