ID   DQA2_HUMAN              Reviewed;         255 AA.
AC   P01906; A2BF37; B0V0E7; O19789; Q5SQ94; Q5SR04;
DT   21-JUL-1986, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1991, sequence version 2.
DT   04-NOV-2026, entry version 210.
DE   RecName: Full=HLA class II histocompatibility antigen, DQ alpha 2 chain;
DE   AltName: Full=DX alpha chain;
DE   AltName: Full=HLA class II histocompatibility antigen, DQ(6) alpha chain;
DE   AltName: Full=HLA-DQA1;
DE   AltName: Full=MHC class II DQA2;
DE   Flags: Precursor;
GN   Name=HLA-DQA2; Synonyms=HLA-DXA;
OS   Homo sapiens (Human).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Euarchontoglires; Primates; Haplorrhini; Catarrhini; Hominidae;
OC   Homo.
OX   NCBI_TaxID=9606;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3036828; DOI=10.1016/s0021-9258(18)47482-0;
RA   Jonsson A.-K., Hyldig-Nielsen J.-J., Servenius B., Larhammar D.,
RA   Andersson G., Joergensen F., Peterson P.A., Rask L.;
RT   "Class II genes of the human major histocompatibility complex. Comparisons
RT   of the DQ and DX alpha and beta genes.";
RL   J. Biol. Chem. 262:8767-8777(1987).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA] (CLONE LAMBDA DCH-10).
RX   PubMed=6584734; DOI=10.1038/308327a0;
RA   Auffray C., Lillie J.W., Arnot D., Grossberger D., Kappes D.,
RA   Strominger J.L.;
RT   "Isotypic and allotypic variation of human class II histocompatibility
RT   antigen alpha-chain genes.";
RL   Nature 308:327-333(1984).
RN   [3]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=3610256; DOI=10.1007/bf00345456;
RA   Auffray C., Lillie J.W., Korman A.J., Boss J.M., Frechin N., Guillemot F.,
RA   Cooper J., Mulligan R.C., Strominger J.L.;
RT   "Structure and expression of HLA-DQ alpha and -DX alpha genes: interallelic
RT   alternate splicing of the HLA-DQ alpha gene and functional splicing of the
RT   HLA-DQ alpha gene using a retroviral vector.";
RL   Immunogenetics 26:63-73(1987).
RN   [4]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA], AND VARIANTS ALA-227 AND
RP   ASP-247.
RX   PubMed=14574404; DOI=10.1038/nature02055;
RA   Mungall A.J., Palmer S.A., Sims S.K., Edwards C.A., Ashurst J.L.,
RA   Wilming L., Jones M.C., Horton R., Hunt S.E., Scott C.E., Gilbert J.G.R.,
RA   Clamp M.E., Bethel G., Milne S., Ainscough R., Almeida J.P., Ambrose K.D.,
RA   Andrews T.D., Ashwell R.I.S., Babbage A.K., Bagguley C.L., Bailey J.,
RA   Banerjee R., Barker D.J., Barlow K.F., Bates K., Beare D.M., Beasley H.,
RA   Beasley O., Bird C.P., Blakey S.E., Bray-Allen S., Brook J., Brown A.J.,
RA   Brown J.Y., Burford D.C., Burrill W., Burton J., Carder C., Carter N.P.,
RA   Chapman J.C., Clark S.Y., Clark G., Clee C.M., Clegg S., Cobley V.,
RA   Collier R.E., Collins J.E., Colman L.K., Corby N.R., Coville G.J.,
RA   Culley K.M., Dhami P., Davies J., Dunn M., Earthrowl M.E., Ellington A.E.,
RA   Evans K.A., Faulkner L., Francis M.D., Frankish A., Frankland J.,
RA   French L., Garner P., Garnett J., Ghori M.J., Gilby L.M., Gillson C.J.,
RA   Glithero R.J., Grafham D.V., Grant M., Gribble S., Griffiths C.,
RA   Griffiths M.N.D., Hall R., Halls K.S., Hammond S., Harley J.L., Hart E.A.,
RA   Heath P.D., Heathcott R., Holmes S.J., Howden P.J., Howe K.L., Howell G.R.,
RA   Huckle E., Humphray S.J., Humphries M.D., Hunt A.R., Johnson C.M.,
RA   Joy A.A., Kay M., Keenan S.J., Kimberley A.M., King A., Laird G.K.,
RA   Langford C., Lawlor S., Leongamornlert D.A., Leversha M., Lloyd C.R.,
RA   Lloyd D.M., Loveland J.E., Lovell J., Martin S., Mashreghi-Mohammadi M.,
RA   Maslen G.L., Matthews L., McCann O.T., McLaren S.J., McLay K., McMurray A.,
RA   Moore M.J.F., Mullikin J.C., Niblett D., Nickerson T., Novik K.L.,
RA   Oliver K., Overton-Larty E.K., Parker A., Patel R., Pearce A.V., Peck A.I.,
RA   Phillimore B.J.C.T., Phillips S., Plumb R.W., Porter K.M., Ramsey Y.,
RA   Ranby S.A., Rice C.M., Ross M.T., Searle S.M., Sehra H.K., Sheridan E.,
RA   Skuce C.D., Smith S., Smith M., Spraggon L., Squares S.L., Steward C.A.,
RA   Sycamore N., Tamlyn-Hall G., Tester J., Theaker A.J., Thomas D.W.,
RA   Thorpe A., Tracey A., Tromans A., Tubby B., Wall M., Wallis J.M.,
RA   West A.P., White S.S., Whitehead S.L., Whittaker H., Wild A., Willey D.J.,
RA   Wilmer T.E., Wood J.M., Wray P.W., Wyatt J.C., Young L., Younger R.M.,
RA   Bentley D.R., Coulson A., Durbin R.M., Hubbard T., Sulston J.E., Dunham I.,
RA   Rogers J., Beck S.;
RT   "The DNA sequence and analysis of human chromosome 6.";
RL   Nature 425:805-811(2003).
RN   [5]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-13.
RX   PubMed=8026991; DOI=10.1016/0198-8859(94)90264-x;
RA   Rudy G., Lew A.M.;
RT   "Limited polymorphism of the HLA-DQA2 promoter and identification of a
RT   variant octamer.";
RL   Hum. Immunol. 39:225-229(1994).
RN   [6]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 41-103.
RX   PubMed=2513578; DOI=10.1073/pnas.86.24.9986;
RA   Gyllensten U.B., Erlich H.A.;
RT   "Ancient roots for polymorphism at the HLA-DQ alpha locus in primates.";
RL   Proc. Natl. Acad. Sci. U.S.A. 86:9986-9990(1989).
RN   [7]
RP   TISSUE SPECIFICITY.
RX   PubMed=9036956; DOI=10.4049/jimmunol.158.5.2116;
RA   Rudy G.B., Lew A.M.;
RT   "The nonpolymorphic MHC class II isotype, HLA-DQA2, is expressed on the
RT   surface of B lymphoblastoid cells.";
RL   J. Immunol. 158:2116-2125(1997).
RN   [8]
RP   REVIEW.
RX   PubMed=8598037; DOI=10.1016/s0092-8674(00)81025-9;
RA   Cresswell P.;
RT   "Invariant chain structure and MHC class II function.";
RL   Cell 84:505-507(1996).
RN   [9]
RP   REVIEW.
RX   PubMed=11684289; DOI=10.1016/s0161-5890(01)00069-4;
RA   Villadangos J.A.;
RT   "Presentation of antigens by MHC class II molecules: getting the most out
RT   of them.";
RL   Mol. Immunol. 38:329-346(2001).
RN   [10]
RP   REVIEW.
RX   PubMed=18046453; DOI=10.1038/sj.emboj.7601945;
RA   Rocha N., Neefjes J.;
RT   "MHC class II molecules on the move for successful antigen presentation.";
RL   EMBO J. 27:1-5(2008).
RN   [11]
RP   REVIEW.
RX   PubMed=17241953; DOI=10.1016/j.immuni.2007.01.005;
RA   Menendez-Benito V., Neefjes J.;
RT   "Autophagy in MHC class II presentation: sampling from within.";
RL   Immunity 26:1-3(2007).
RN   [12]
RP   REVIEW.
RX   PubMed=19092054; DOI=10.1242/jcs.035089;
RA   Berger A.C., Roche P.A.;
RT   "MHC class II transport at a glance.";
RL   J. Cell Sci. 122:1-4(2009).
RN   [13]
RP   REVIEW.
RX   PubMed=19533806; DOI=10.3748/wjg.15.2855;
RA   Beswick E.J., Reyes V.E.;
RT   "CD74 in antigen presentation, inflammation, and cancers of the
RT   gastrointestinal tract.";
RL   World J. Gastroenterol. 15:2855-2861(2009).
RN   [14]
RP   FUNCTION, INTERACTION WITH CD74; HLA-DMA; HLA-DQB1 AND HLA-DQB2,
RP   SUBCELLULAR LOCATION, AND TISSUE SPECIFICITY.
RX   PubMed=22407913; DOI=10.4049/jimmunol.1103048;
RA   Lenormand C., Bausinger H., Gross F., Signorino-Gelo F., Koch S.,
RA   Peressin M., Fricker D., Cazenave J.P., Bieber T., Hanau D.,
RA   de la Salle H., Tourne S.;
RT   "HLA-DQA2 and HLA-DQB2 genes are specifically expressed in human Langerhans
RT   cells and encode a new HLA class II molecule.";
RL   J. Immunol. 188:3903-3911(2012).
CC   -!- FUNCTION: Binds peptides derived from antigens that access the
CC       endocytic route of antigen presenting cells (APC) and presents them on
CC       the cell surface for recognition by the CD4 T-cells. The peptide
CC       binding cleft accommodates peptides of 10-30 residues. The peptides
CC       presented by MHC class II molecules are generated mostly by degradation
CC       of proteins that access the endocytic route, where they are processed
CC       by lysosomal proteases and other hydrolases. Exogenous antigens that
CC       have been endocytosed by the APC are thus readily available for
CC       presentation via MHC II molecules, and for this reason this antigen
CC       presentation pathway is usually referred to as exogenous. As membrane
CC       proteins on their way to degradation in lysosomes as part of their
CC       normal turn-over are also contained in the endosomal/lysosomal
CC       compartments, exogenous antigens must compete with those derived from
CC       endogenous components. Autophagy is also a source of endogenous
CC       peptides, autophagosomes constitutively fuse with MHC class II loading
CC       compartments. In addition to APCs, other cells of the gastrointestinal
CC       tract, such as epithelial cells, express MHC class II molecules and
CC       CD74 and act as APCs, which is an unusual trait of the GI tract. To
CC       produce a MHC class II molecule that presents an antigen, three MHC
CC       class II molecules (heterodimers of an alpha and a beta chain)
CC       associate with a CD74 trimer in the ER to form a heterononamer. Soon
CC       after the entry of this complex into the endosomal/lysosomal system
CC       where antigen processing occurs, CD74 undergoes a sequential
CC       degradation by various proteases, including CTSS and CTSL, leaving a
CC       small fragment termed CLIP (class-II-associated invariant chain
CC       peptide). The removal of CLIP is facilitated by HLA-DM via direct
CC       binding to the alpha-beta-CLIP complex so that CLIP is released. HLA-DM
CC       stabilizes MHC class II molecules until primary high affinity antigenic
CC       peptides are bound. The MHC II molecule bound to a peptide is then
CC       transported to the cell membrane surface. In B-cells, the interaction
CC       between HLA-DM and MHC class II molecules is regulated by HLA-DO.
CC       Primary dendritic cells (DCs) also to express HLA-DO. Lysosomal
CC       microenvironment has been implicated in the regulation of antigen
CC       loading into MHC II molecules, increased acidification produces
CC       increased proteolysis and efficient peptide loading.
CC       {ECO:0000269|PubMed:22407913}.
CC   -!- SUBUNIT: Heterodimer of an alpha and a beta subunit; also referred as
CC       MHC class II molecule. Dimer formation with HLA-DQB2, but not with HLA-
CC       DQB1, is required for efficient exit from the endoplasmic reticulum
CC       (ER). In the ER, forms a heterononamer; 3 MHC class II molecules bind
CC       to a CD74 homotrimer (also known as invariant chain or HLA class II
CC       histocompatibility antigen gamma chain). In the endosomal/lysosomal
CC       system; CD74 undergoes sequential degradation by various proteases;
CC       leaving a small fragment termed CLIP on each MHC class II molecule. MHC
CC       class II molecule interacts with HLA_DM, and HLA_DO in B-cells, in
CC       order to release CLIP and facilitate the binding of antigenic peptides.
CC       Association with HLA-DMA also occurs in skin Langerhans cells, in post-
CC       Golgi compartments. {ECO:0000269|PubMed:22407913}.
CC   -!- INTERACTION:
CC       P01906; Q8TAF8: LHFPL5; NbExp=3; IntAct=EBI-19949550, EBI-2820517;
CC   -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000269|PubMed:22407913};
CC       Single-pass type I membrane protein {ECO:0000269|PubMed:22407913}.
CC       Endoplasmic reticulum membrane {ECO:0000269|PubMed:22407913}; Single-
CC       pass type I membrane protein {ECO:0000269|PubMed:22407913}. Golgi
CC       apparatus, trans-Golgi network membrane {ECO:0000269|PubMed:22407913};
CC       Single-pass type I membrane protein {ECO:0000269|PubMed:22407913}.
CC       Endosome membrane {ECO:0000269|PubMed:22407913}; Single-pass type I
CC       membrane protein {ECO:0000269|PubMed:22407913}. Lysosome membrane
CC       {ECO:0000269|PubMed:22407913}; Single-pass type I membrane protein
CC       {ECO:0000269|PubMed:22407913}. Note=The MHC class II complex transits
CC       through a number of intracellular compartments in the endocytic pathway
CC       until it reaches the cell membrane for antigen presentation.
CC   -!- TISSUE SPECIFICITY: Restricted to skin Langerhans cells, although some
CC       expression at low levels may occur at the surface of B lymphoblastoid
CC       cells. {ECO:0000269|PubMed:22407913, ECO:0000269|PubMed:9036956}.
CC   -!- SIMILARITY: Belongs to the MHC class II family. {ECO:0000305}.
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DR   EMBL; M29615; AAA59834.1; -; Genomic_DNA.
DR   EMBL; M29614; AAA59834.1; JOINED; Genomic_DNA.
DR   EMBL; X00453; CAA25142.1; -; Genomic_DNA.
DR   EMBL; X00454; CAA25142.1; JOINED; Genomic_DNA.
DR   EMBL; X00455; CAA25142.1; JOINED; Genomic_DNA.
DR   EMBL; X00456; CAA25142.1; JOINED; Genomic_DNA.
DR   EMBL; M17237; AAA59605.1; -; Genomic_DNA.
DR   EMBL; M17235; AAA59605.1; JOINED; Genomic_DNA.
DR   EMBL; AL773543; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; CR759848; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; BX927131; CAM26196.1; -; Genomic_DNA.
DR   EMBL; BX248406; CAM26196.1; JOINED; Genomic_DNA.
DR   EMBL; AL672104; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; AL713890; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; BX927160; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; BX927168; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; CR753846; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; CR936921; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   EMBL; S71248; AAD14077.1; -; Genomic_DNA.
DR   CCDS; CCDS4753.1; -.
DR   PIR; A02210; HLHUDX.
DR   PIR; I54439; I54439.
DR   RefSeq; NP_064440.1; NM_020056.5.
DR   AlphaFoldDB; P01906; -.
DR   SMR; P01906; -.
DR   BioGRID; 109363; 2.
DR   FunCoup; P01906; 448.
DR   IntAct; P01906; 2.
DR   NDEx; IQUERY-CP-HLA-DQA2; 3 NDEx IQuery Curated Pathways.
DR   STRING; 9606.ENSP00000364076; -.
DR   GlyCosmos; P01906; 3 sites, No reported glycans.
DR   GlyGen; P01906; 3 sites.
DR   iPTMnet; P01906; -.
DR   PhosphoSitePlus; P01906; -.
DR   BioMuta; HLA-DQA2; -.
DR   DMDM; 122192; -.
DR   jPOST; P01906; -.
DR   MassIVE; P01906; -.
DR   PaxDb; 9606-ENSP00000364076; -.
DR   PeptideAtlas; P01906; -.
DR   Antibodypedia; 48442; 255 antibodies from 30 providers.
DR   DNASU; 3118; -.
DR   Ensembl; ENST00000241802.9; ENSP00000241802.5; ENSG00000206301.9.
DR   Ensembl; ENST00000374940.4; ENSP00000364076.3; ENSG00000237541.4.
DR   Ensembl; ENST00000415898.2; ENSP00000400695.2; ENSG00000231526.3.
DR   Ensembl; ENST00000443184.2; ENSP00000405833.2; ENSG00000257473.7.
DR   Ensembl; ENST00000446482.2; ENSP00000390725.2; ENSG00000225103.3.
DR   Ensembl; ENST00000447735.5; ENSP00000393431.1; ENSG00000223793.7.
DR   Ensembl; ENST00000449560.5; ENSP00000401098.1; ENSG00000233192.7.
DR   Ensembl; ENST00000453672.2; ENSP00000387768.2; ENSG00000231823.3.
DR   Ensembl; ENST00000546801.2; ENSP00000447668.1; ENSG00000233192.7.
DR   Ensembl; ENST00000551533.1; ENSP00000448003.1; ENSG00000223793.7.
DR   GeneID; 3118; -.
DR   KEGG; hsa:3118; -.
DR   MANE-Select; ENST00000374940.4; ENSP00000364076.3; NM_020056.5; NP_064440.1.
DR   UCSC; uc003obx.4; human.
DR   AGR; HGNC:4943; -.
DR   ClinPGx; PA35067; -.
DR   CTD; 3118; -.
DR   DisGeNET; 3118; -.
DR   GeneCards; HLA-DQA2; -.
DR   HGNC; HGNC:4943; HLA-DQA2.
DR   HPA; ENSG00000237541; Tissue enhanced (lung, lymphoid tissue).
DR   MIM; 613503; gene.
DR   OpenTargets; ENSG00000237541; -.
DR   VEuPathDB; HostDB:ENSG00000237541; -.
DR   eggNOG; ENOG502RXYJ; Eukaryota.
DR   GeneTree; ENSGT00940000162892; -.
DR   HOGENOM; CLU_069380_0_0_1; -.
DR   InParanoid; P01906; -.
DR   OMA; AAYGINM; -.
DR   OrthoDB; 8925804at2759; -.
DR   PAN-GO; P01906; 9 GO annotations based on evolutionary models.
DR   PhylomeDB; P01906; -.
DR   PathwayCommons; P01906; -.
DR   Reactome; R-HSA-202424; Downstream TCR signaling.
DR   Reactome; R-HSA-202427; Phosphorylation of CD3 and TCR zeta chains.
DR   Reactome; R-HSA-202430; Translocation of ZAP-70 to Immunological synapse.
DR   Reactome; R-HSA-202433; Generation of second messenger molecules.
DR   Reactome; R-HSA-2132295; MHC class II antigen presentation.
DR   Reactome; R-HSA-389948; Co-inhibition by PD-1.
DR   Reactome; R-HSA-877300; Interferon gamma signaling.
DR   Reactome; R-HSA-9938027; Affinity selection of immunoglobulins.
DR   Reactome; R-HSA-9979719; Processing of antigen in germinal center B cells.
DR   SignaLink; P01906; -.
DR   SIGNOR; P01906; -.
DR   Agora; ENSG00000237541; -.
DR   BioGRID-ORCS; 3118; 12 hits in 1136 CRISPR screens.
DR   ChiTaRS; HLA-DQA2; human.
DR   GeneWiki; HLA-DQA2; -.
DR   GenomeRNAi; 3118; -.
DR   Pharos; P01906; Tbio.
DR   PRO; PR:P01906; -.
DR   Proteomes; UP000005640; Chromosome 6.
DR   RNAct; P01906; protein.
DR   Bgee; ENSG00000206301; Expressed in nasopharynx and 8 other cell types or tissues.
DR   ExpressionAtlas; P01906; baseline and differential.
DR   GO; GO:0030669; C:clathrin-coated endocytic vesicle membrane; TAS:Reactome.
DR   GO; GO:0030666; C:endocytic vesicle membrane; TAS:Reactome.
DR   GO; GO:0012507; C:ER to Golgi transport vesicle membrane; TAS:Reactome.
DR   GO; GO:0000139; C:Golgi membrane; TAS:Reactome.
DR   GO; GO:0031902; C:late endosome membrane; IBA:GO_Central.
DR   GO; GO:0098553; C:lumenal side of endoplasmic reticulum membrane; TAS:Reactome.
DR   GO; GO:0005765; C:lysosomal membrane; IBA:GO_Central.
DR   GO; GO:0042613; C:MHC class II protein complex; IBA:GO_Central.
DR   GO; GO:0005886; C:plasma membrane; TAS:Reactome.
DR   GO; GO:0032588; C:trans-Golgi network membrane; TAS:Reactome.
DR   GO; GO:0030658; C:transport vesicle membrane; TAS:Reactome.
DR   GO; GO:0023026; F:MHC class II protein complex binding; IBA:GO_Central.
DR   GO; GO:0032395; F:MHC class II receptor activity; NAS:UniProtKB.
DR   GO; GO:0042605; F:peptide antigen binding; IBA:GO_Central.
DR   GO; GO:0019886; P:antigen processing and presentation of exogenous peptide antigen via MHC class II; IBA:GO_Central.
DR   GO; GO:0006955; P:immune response; NAS:UniProtKB.
DR   GO; GO:0002503; P:peptide antigen assembly with MHC class II protein complex; IBA:GO_Central.
DR   GO; GO:0050778; P:positive regulation of immune response; IBA:GO_Central.
DR   GO; GO:0050870; P:positive regulation of T cell activation; IBA:GO_Central.
DR   CDD; cd21008; IgC1_MHC_II_alpha_HLA-DQ; 1.
DR   FunFam; 2.60.40.10:FF:000280; HLA class II histocompatibility antigen, DR alpha chain; 1.
DR   FunFam; 3.10.320.10:FF:000002; HLA class II histocompatibility antigen, DR alpha chain; 1.
DR   Gene3D; 3.10.320.10; Class II Histocompatibility Antigen, M Beta Chain, Chain B, domain 1; 1.
DR   Gene3D; 2.60.40.10; Immunoglobulins; 1.
DR   InterPro; IPR007110; Ig-like_dom.
DR   InterPro; IPR036179; Ig-like_dom_sf.
DR   InterPro; IPR013783; Ig-like_fold.
DR   InterPro; IPR003006; Ig/MHC_CS.
DR   InterPro; IPR003597; Ig_C1-set.
DR   InterPro; IPR050160; MHC/Immunoglobulin.
DR   InterPro; IPR011162; MHC_I/II-like_Ag-recog.
DR   InterPro; IPR014745; MHC_II_a/b_N.
DR   InterPro; IPR001003; MHC_II_a_N.
DR   PANTHER; PTHR19944:SF94; HLA CLASS II HISTOCOMPATIBILITY ANTIGEN, DQ ALPHA 2 CHAIN; 1.
DR   PANTHER; PTHR19944; MHC CLASS II-RELATED; 1.
DR   Pfam; PF07654; C1-set; 1.
DR   Pfam; PF00993; MHC_II_alpha; 1.
DR   SMART; SM00407; IGc1; 1.
DR   SMART; SM00920; MHC_II_alpha; 1.
DR   SUPFAM; SSF48726; Immunoglobulin; 1.
DR   SUPFAM; SSF54452; MHC antigen-recognition domain; 1.
DR   PROSITE; PS50835; IG_LIKE; 1.
DR   PROSITE; PS00290; IG_MHC; 1.
PE   1: Evidence at protein level;
KW   Adaptive immunity; Cell membrane; Disulfide bond; Endoplasmic reticulum;
KW   Endosome; Glycoprotein; Golgi apparatus; Immunity; Lysosome; Membrane;
KW   MHC II; Proteomics identification; Reference proteome; Signal;
KW   Transmembrane; Transmembrane helix.
FT   SIGNAL          1..23
FT   CHAIN           24..255
FT                   /note="HLA class II histocompatibility antigen, DQ alpha 2
FT                   chain"
FT                   /id="PRO_0000018973"
FT   TOPO_DOM        24..217
FT                   /note="Extracellular"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        218..240
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        241..255
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   DOMAIN          113..205
FT                   /note="Ig-like C1-type"
FT   REGION          24..110
FT                   /note="Alpha-1"
FT   REGION          111..204
FT                   /note="Alpha-2"
FT   REGION          205..217
FT                   /note="Connecting peptide"
FT   CARBOHYD        104
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        144
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        133..189
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   VARIANT         227
FT                   /note="V -> A (in dbSNP:rs9276436)"
FT                   /evidence="ECO:0000269|PubMed:14574404"
FT                   /id="VAR_033431"
FT   VARIANT         247
FT                   /note="G -> D (in dbSNP:rs2071800)"
FT                   /evidence="ECO:0000269|PubMed:14574404"
FT                   /id="VAR_050392"
FT   CONFLICT        84
FT                   /note="S -> T (in Ref. 1; AAA59834)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        101
FT                   /note="R -> G (in Ref. 4; CAM26196)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   255 AA;  28033 MW;  85B13D9FDF2905FE CRC64;
     MILNKALLLG ALALTAVMSP CGGEDIVADH VASYGVNFYQ SHGPSGQYTH EFDGDEEFYV
     DLETKETVWQ LPMFSKFISF DPQSALRNMA VGKHTLEFMM RQSNSTAATN EVPEVTVFSK
     FPVTLGQPNT LICLVDNIFP PVVNITWLSN GHSVTEGVSE TSFLSKSDHS FFKISYLTFL
     PSADEIYDCK VEHWGLDEPL LKHWEPEIPA PMSELTETLV CALGLSVGLM GIVVGTVFII
     QGLRSVGASR HQGLL
//