On viral infection PCB2 binds MAVS/IPS-1 and recruits the HECT domain-containing E3 ligase AIP4/ITCHY. AIP4 catalyses K48-polyubiquitination and degradation of MAVS. PCBP2 overexpression enhanced the interaction between MAVS and AIP4 and led to more degradation of MAVS. MAVS/IPS-1 regulation is very important in preventing excessive harmful immune responses.
ubiquitin protein ligase activity of ITCH [cytosol]