HLA-A belongs to the HLA class I heavy chain paralogues. This class I molecule is a heterodimer consisting of a heavy chain and a light chain (beta-2 microglobulin). The heavy chain is anchored in the membrane. Class I molecules play a central role in the immune system by presenting peptides derived from the endoplasmic reticulum lumen. They are expressed in nearly all cells. The heavy chain is approximately 45 kDa and its gene contains 8 exons. Exon 1 encodes the leader peptide, exons 2 and 3 encode the alpha1 and alpha2 domains, which both bind the peptide, exon 4 encodes the alpha3 domain, exon 5 encodes the transmembrane region, and exons 6 and 7 encode the cytoplasmic tail. Polymorphisms within exon 2 and exon 3 are responsible for the peptide binding specificity of each class one molecule. Typing for these polymorphisms is routinely done for bone marrow and kidney transplantation. Hundreds of HLA-A alleles have been described.
A29 protein; antigen presenting molecule; DAQB-90C11.16; FLJ26655; HLA A; HLA class I antigen; HLA class I histocompatibility antigen, A-1 alpha chain; HLA class I histocompatibility antigen, A-3 alpha chain; HLA class I histocompatibility antigen, A-30 alpha chain; HLA class I histocompatibility antigen, A-33 alpha chain; HLA class I histocompatibility antigen, A-74 alpha chain; HLA locus; HLA-A locus alpha 2 domain; HLA-A null; HLA-A*01; HLA-Aw33.1; HLAA; Human leukocyte antigen A*01; leukocyte antigen class I-A; MCH class I antigen; MHC 1; MHC class 1 antigen; MHC class I anti; MHC Class I antigen; MHC class I antigen A*3; MHC class I antigen A*30; MHC class I antigen A*33; MHC class I antigen A*74; MHC class I antigen heavy chain; MHC class I antigen HLA-A heavy chain; MHC class I antigen HLA-A33; MHC class I antigen null protein; MHC class I antigene; MHC class II antigen; MHC classI antigen; MHC1; truncated MHC class I antigen