Background
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 trans
Function
function:Involved in the presentation of foreign antigens to the immune system.,polymorphism:The following alleles of A-1 are known: A*0101, A*0102, A*0103, A*0106 and A*0107. The sequence shown is that of A*0101.,polymorphism:The following alleles of A-11 are known: A*1101 (A-11E), A*1102 (A-11K), A*1103, A*1104, A*1105 and A*1107. The sequence shown is that of A*1101.,polymorphism:The following alleles of A-2 are known: A*0201, A*0202, A*0203, A*0204, A*0205, A*0206 (A2.4A), A*0207, A*0208, A*0209, A*0210, A*0211 (A2.5), A*0212, A*0213 (A*02SLU), A*0216, A*0217, A*0218 (A2K), A*0219, A*0220, A*0221, A*0231, A*0234 (A*AAT), A*0235, A*0236 and A*0237. The sequence shown is that of A*0201.,polymorphism:The following alleles of A-23 are known: A*2301, A*2302, A*2303, A*2304 and A*2305. The sequence shown is that of A*2301.,polymorphism:The following alleles of A-24 are known: A*2401, A*240
