E3 ubiquitin-protein ligase that mediates ubiquitination and subsequent proteasomal degradation of target proteins, such as RIGI, MAVS/IPS1, IFIH1/MDA5, JAK1 and p53/TP53.Acts as a negative regulator of type I interferon production by mediating ubiquitination of RIGI at 'Lys-181', leading to RIGI degradation.