A Novel Mitochondrial MAVS/Caspase-8 Platform Links RNA Virus-Induced Innate Antiviral Signaling to Bax/Bak-Independent Apoptosis
Abstract:
Semliki Forest virus (SFV) requires RNA replication and Bax/Bak for efficient apoptosis induction. However, cells lacking Bax/Bak continue to die in a caspase-dependent manner. In this study, we show in both mouse and human cells that this Bax/Bak-independent pathway involves dsRNA-induced innate immune signaling via mitochondrial antiviral signaling (MAVS) and caspase-8. Bax/Bak-deficient or Bcl-2- or Bcl-xL-overexpressing cells lacking MAVS or caspase-8 expression are resistant to SFV-induced apoptosis. The signaling pathway triggered by SFV does neither involve death receptors nor the classical MAVS effectors TNFR-associated factor-2, IRF-3/7, or IFN-β but the physical interaction of MAVS with caspase-8 on mitochondria in a FADD-independent manner. Consistently, caspase-8 and -3 activation are reduced in MAVS-deficient cells. Thus, after RNA virus infection MAVS does not only elicit a type I antiviral response but also recruits caspase-8 to mitochondria to mediate caspase-3 activation and apoptosis in a Bax/Bak-independent manner.
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J. Immunol.
J. Immunol. 192(3): 1171-83
3rd Jan 2014
Souhayla El Maadidi, Laura Faletti, Birgit Berg, Christin Wenzl, Katrin Wieland, Zhijian J Chen, Ulrich Maurer, Christoph Borner
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- Created: 22nd Jan 2014 at 15:15
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