major histocompatibility complex, class ii, dq alpha 1 major histocompatibility complex, class ii, dq alpha 1 major histocompatibility complex, class ii, dq alpha 1, also known as hla-dqa1, is a human gene present on short arm of chromosome 6 (6p21.3) and also denotes the genetic locus which contains this gene. the protein encoded by this gene is one of two proteins that are required to form the dq heterodimer, a cell surface receptor essential to the function of the immune system. hla-dqa1available structurespdbortholog search: pdbe rcsb list of pdb id codes1jk8, 1s9v, 2nna, 4gg6, 4ozf, 4ozg, 4ozh, 4oziidentifiersaliaseshla-dqa1, cd, celiac1, dq-a1, gse, hla-dqa, major histocompatibility complex, class ii, dq alpha 1, dqa1external idsomim: 146880 mgi: 95895 homologene: 123820 genecards: hla-dqa1 gene location (human)chr.chromosome 6 (human)band6p21.32start32,628,179 bpend32,647,062 bpgene location (mouse)chr.chromosome 17 (mouse)band17 b1|17 17.98 cmstart34,501,718 bpend34,506,797 bprna expression patternbgeehumanmouse (ortholog)top expressed ingallbladderrectummonocyteright lungvisceral pleuraspleenlymph nodeupper lobe of left lungappendixright coronary arterytop expressed inspleenpaneth cellthymussubmandibular glandright lungright lung lobesuperior surface of tonguewhite adipose tissueright ventriclecarotid bodymore reference expression databiogpsn/agene ontologymolecular function peptide antigen binding mhc class ii receptor activity protein binding cellular component integral component of membrane endocytic vesicle membrane clathrin-coated endocytic vesicle membrane endosome golgi apparatus trans-golgi network membrane endoplasmic reticulum membrane membrane golgi membrane plasma membrane transport vesicle membrane integral component of plasma membrane mhc class ii protein complex lysosomal membrane endoplasmic reticulum er to golgi transport vesicle membrane lysosome integral component of lumenal side of endoplasmic reticulum membrane endosome membrane biological process antigen processing and presentation antigen processing and presentation of exogenous peptide antigen via mhc class ii interferon-gamma-mediated signaling pathway immune system process t cell costimulation antigen processing and presentation of peptide or polysaccharide antigen via mhc class ii immune response t cell receptor signaling pathway adaptive immune response sources:amigo / quickgoorthologsspecieshumanmouseentrez311714960ensemblensg00000236418ensg00000206305ensg00000225890ensg00000232062ensg00000196735ensg00000228284ensmusg00000036594uniprotp01909p14434p14437p01910p14435p14438p04228p14436p04227refseq (mrna)nm_002122nm_010378refseq (protein)np_002113np_034508location (ucsc)chr 6: 32.63 – 32.65 mbchr 17: 34.5 – 34.51 mbpubmed searchwikidataview/edit humanview/edit mouse function hla-dqa1 belongs to the hla class ii alpha chain paralogues. this class ii molecule is a heterodimer consisting of an alpha (dqa) and a beta chain (dqb), 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). gene structure and polymorphisms the alpha chain contains 5 exons. exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular protein domains, exon 4 encodes the transmembrane domain and the cytoplasmic tail. within the dq molecule both the alpha chain and the beta chain contain the polymorphisms specifying the peptide binding specificities, resulting in up to 4 different molecules. typing for these polymorphisms is routinely done for bone marrow transplantation. alleles dq1 there are four commonly encountered dqa1 alleles: dqa1*0101, *0102, *0103, *0104. these alleles are always found in haplotypes with hla-dqb1*05 (dq5) and hla-dqb1*06 (dq6). dq1 is a serotype, rare among serotypes for human class ii antigens, in that the antibodies to dq1 react to the alpha chain of hla dq, these dqa1 allele gene products. hla-dqa1 alleles dqa1linked dqb1 allele dq1*0101*0501*0301 *0102*0502*0504*0602*0604*0605*0609 *0103*0501*0502*0601*0602*0603 *0104*0501*0503*0602 *0105rare *0106rare see haplotype table in hla-dq. unbolded are rare haplotypes link to haplotypes can be followed by dqb1 alleles other the other dqa1 alleles have no defined serotype. there are 5 groups, dqa1*02, *03, *04, *05, *06. dqa1 within these groups are either invariant or produce the same α-chain subunit. dqa1*02 and dqa1*06 contain only one allele. dqa1*03 has three alleles which each produce nearly identical α3. for dqa1*05, the dqa1*0501 and dqa1*0505 produce identical α5. other dqa1*05 exist that produce variant α5var, but these are rare. hla-dqa1 alleles dqa1linked dqb1 allele *0201*0202*0303 *0301*0202*0302 *0302 *0303*0301*0602 *0401*0303*0401*0402 *0501*0201 *0505*0301 *0601*0301 see haplotype table in hla-dq. unbolded are rare haplotypes link to haplotypes can be followed by dqb1 alleles