Involved in the presentation of foreign antigens to the immune system. Heterodimer of an alpha chain and a beta chain (beta-2-microglobulin). Interacts with murid herpesvirus 4 protein K3 (mK3). Polyubiquitinated in case of infection by murid herpesvirus 4, by the viral E3 ligase K3 (mK3). This modification causes the protein to be targeted for rapid degradation by the endoplasmic reticulum-associated degradation (ERAD) system. Ubiquitination occurs on lysine, as well as serine and threonine residues present in the cytoplasmic tail. Serine and threonine residues are subject to ubiquitination via ester bonds instead of the usual isopeptide linkage. Belongs to the MHC class I family. Truncated N-terminus.