HLA-A, B, and C are transmembrane glycoproteins in the major histocompatibility complex 1 (MHC I) family. The C receptor is a heterodimer consisting of a HLA-C mature gene product (heavy chain) and β2-microglobulin (light chain). The mature C chain is anchored in the membrane. HLA class I molecules play a central role in the immune system by presenting peptides derived from endoplasmic reticulum lumen. HLA-C are expressed in nearly all cells, and present small peptides to the immune system which surveys for non-self peptides.