MAVS regulates apoptotic cell death by decreasing K48-linked ubiquitination of voltage-dependent anion channel 1.

The mitochondrial antiviral signaling protein MAVS (IPS-1, VISA, or Cardif) plays an important role in the host defense against viral infection by inducing type I interferon. Recent reports have shown that MAVS is also critical for virus-induced apoptosis. However, the mechanism of MAVS-mediated apoptosis induction remains unclear. Here, we show that MAVS binds to voltage-dependent anion channel 1 (VDAC1) and induces apoptosis by caspase-3 activation, which is independent of its role in innate immunity. MAVS modulates VDAC1 protein stability by decreasing its degradative K48-linked ubiquitination. In addition, MAVS knockout mouse embryonic fibroblasts (MEFs) display reduced VDAC1 expression with a consequent reduction of the vesicular stomatitis virus (VSV)-induced apoptosis response. Notably, the upregulation of VDAC1 triggered by VSV infection is completely abolished in MAVS knockout MEFs. We thus identify VDAC1 as a target of MAVS and describe a novel mechanism of MAVS control of virus-induced apoptotic cell death.