HLA-DRA

HLA-DRA是HLAⅡ类α链的一种。这种II类分子是一种由α链和β链组成的异二聚体，它们都锚定在膜中。通过呈现细胞外蛋白衍生的肽，在免疫系统中起到中心作用。Ⅱ类分子在抗原呈递细胞（APC:B淋巴细胞、树突状细胞、巨噬细胞）中表达。α链约为33-35kDa，其基因包含5个外显子。外显子1编码先导肽，外显子2和3编码两个胞外结构域，外显子4编码跨膜结构域和胞质尾。DRA在肽结合部分没有多态性，是DRB1、DRB3、DRB4和DRB5的唯一α链。
HLA-DRA is one of the HLA class II alpha chain paralogues. This class II molecule is a heterodimer consisting of an alpha and a beta chain, both anchored in the membrane. It plays a central role in the immune system by presenting peptides derived from extracellular proteins. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages). The alpha chain is approximately 33-35 kDa and its gene contains 5 exons. Exon 1 encodes the leader peptide, exons 2 and 3 encode the two extracellular domains, and exon 4 encodes the transmembrane domain and the cytoplasmic tail. DRA does not have polymorphisms in the peptide binding part and acts as the sole alpha chain for DRB1, DRB3, DRB4 and DRB5.