| description | A heterodimeric membrane protein composed of two non-covalently linked polypeptide chains, a major histocompatibility complex (MHC)-encoded alpha chain and a non-MHC-encoded subunit B2M/beta2-microglobulin Each MHC molecule consists of an extracellular peptide-binding cleft, followed by an immunoglobulin (Ig)-like domain and transmembrane and cytoplasmic domains. The amino-terminal alpha-1 and alpha-2 segments of the alpha chain form the peptide-binding cleft. Expressed on all nucleated cells, displays peptides derived from cytosolic proteins for recognition by CD8-positive T cells. By scanning MHC I molecules, CD8- positive T cells can detect infected or tumor cells and eliminate them |
