HLA-DRA

HLA class II histocompatibility antigen, DR alpha chain is a protein that in humans is encoded by the HLA-DRA gene.[5] HLA-DRA encodes the alpha subunit of HLA-DR. Unlike the alpha chains of other Human MHC class II molecules, the alpha subunit is practically invariable. However it can pair with, in any individual, the beta chain from 3 different DR beta loci, DRB1, and two of any DRB3, DRB4, or DRB5 alleles. Thus there is the potential that any given individual can form 4 different HLA-DR isoforms (2 alleles of DRB1 and two alleles from DRB3, DRB4 or DRB5).

HLA-DRA
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesHLA-DRA, HLA-DRA1, MLRW, major histocompatibility complex, class II, DR alpha
External IDsOMIM: 142860 MGI: 95900 HomoloGene: 7751 GeneCards: HLA-DRA
Gene location (Human)
Chr.Chromosome 6 (human)[1]
Band6p21.32Start32,439,878 bp[1]
End32,445,046 bp[1]
RNA expression pattern
More reference expression data
Orthologs
SpeciesHumanMouse
Entrez

3122

100504404

Ensembl

ENSMUSG00000036322

UniProt

P01903

P04224
P01904

RefSeq (mRNA)

NM_019111

NM_010381

RefSeq (protein)

NP_061984

NP_034511

Location (UCSC)Chr 6: 32.44 – 32.45 MbChr 17: 34.34 – 34.34 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Function

The polypeptide subunit encoded by this gene belongs to the HLA class II alpha chain paralogues. The class II protein is a heterodimer consisting of an alpha (DRα) and a beta chain (DRβ), 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).[5]

Gene structure and polymorphisms

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.[5]

Alleles

There are two different HLA-DRA chains in the human population coded by three different DRA alleles:

DRA*01:01
DRA*01:02:01
DRA*01:02:02
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See also

References

Further reading

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