Function
In case of infection by the murid herpesvirus 4, its association with the viral E3 ligase K3 mediates ubiquitination of host surface class I (MHC-I) H-2D(b)/H2-D1 and H-2K(b)/H2-K1 molecules before they exit the endoplasmic reticulum, leading to their degradation by the ERAD system, thus blocking the immune detection of virus-infected cells. The complex formed with the murid herpesvirus 4 protein K3 mediates ubiquitination of lysine, as well as serine and threonine residues present in the cytoplasmic tail of surface class I molecules and promotes ubiquitination of hydroxylated serine or threonine residues via ester bonds instead of the classical isopeptide linkage.