The Otubain YOD1 Suppresses Aggregation and Activation of the Signaling Adaptor MAVS through Lys63-Linked Deubiquitination

MAVS is a critical adaptor required for activating an innate antiviral immune response against viral infection. The activation of MAVS requires modification of the Lys63-linked ubiquitination and formation of prion-like aggregates. However, the molecular mechanisms regulating MAVS activity remain largely obscured. In this study, we identified a deubiquitinase YOD1, also known as a member of the ovarian tumor family, as a negative regulator of MAVS activation in both human and murine cells. YOD1 was recruited to mitochondria to interact with MAVS through its UBX and Znf domains after viral infection. Subsequently, YOD1 cleaved the K63-linked ubiquitination and abrogated the formation of prion-like aggregates of MAVS, which led to attenuation of IRF3, P65 activation, and IFN-β production. Knockdown of YOD1 potentiated IRF3 and P65 activation, IFN-β production, and antiviral innate immune response to RNA virus. Our findings thus provided, to our knowledge, novel insights into the regulatory cascade of the cellular antiviral response through YOD1-mediated K63-linked deubiquitination and aggregation of MAVS.