Major Histocompatibility Complex Class I C (HLA-C) belongs to the HLA class I heavy chain paralogues. The HLA-C (class I molecule) is a heterodimer comprised of a heavy chain and a light chain (beta-2 microglobulin). The heavy chain is anchored in the membrane. Class I molecules have a key role in the immune system by presenting peptides derived from endoplasmic reticulum lumen. Class I molecules are expressed in virtually all cells.