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Major histocompatibility complex, class II, DQ
Structure of HLA-DQB1 (green) complexed with HLA-DQA1 (cyan) and HCRT (magenta) based on PDB 1uvq.
Available structures
1jk8, 1s9v
Identifiers
Symbols	HLA-DQB1; CELIAC1; HLA-DQB; IDDM1
External IDs	OMIM: 604305 GeneCards: HLA-DQB1 Gene
Gene ontology Molecular function • GTP binding • MHC class II receptor activity Cellular component • membrane • integral to membrane • MHC class II protein complex Biological process • antigen processing and presentation of peptide or polysaccharide antigen via MHC class II • immune response • cell cycle
RNA expression pattern
More reference expression data
Orthologs
Species	Human	Mouse
Entrez	3119	n/a
Ensembl	ENSG00000206237	n/a
UniProt	P01918	n/a
RefSeq (mRNA)	NM_002123	n/a
RefSeq (protein)	NP_002114	n/a
Location (UCSC)	Chr c6_COX: 32.7 - 32.7 Mb	n/a
PubMed search	[1]	n/a

Major histocompatibility complex, class II, DQ beta 1, also known as HLA-DQB1, is a human gene and also denotes the genetic locus which contains this gene.^[1] 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.

Function

HLA-DQB1 belongs to the HLA class II beta 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).^[1]

Gene structure and polymorphisms

The beta chain is approximately 26-28 kDa and it 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 exon 5 encodes 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.^[1][2]

Disease association

Diabetes

Several alleles of HLA-DQB1 are associated with an increased risk of developing type 1 diabetes.^[3][4][5] The locus also has the genetic name IDDM1 as it is the highest genetic risk for type 1 diabetes. Again the DQB1*0201 and DQB1*0302 alleles, particularly the phenotype DQB1*0201/*0302 has a high risk of late onset type 1 diabetes. The risk is partially shared with the HLA-DR locus (DR3 and DR4 serotypes).

Coeliac disease

Celiac1 is a genetic name for DQB1, the HLA DQB1*0201, *0202, and *0302 encode genes that mediate the autoimmune coeliac disease. Homozygotes of DQB1*0201 have a higher risk of developing the coeliac disease, relative to any other genetic locus.^[6]

Multiple sclerosis

Certain HLA-DQB1 alleles are also linked to a modest increased risk of multiple sclerosis.^[7][8]

Narcolepsy

Other HLA-DQB1 alleles are associated with a predisposition to narcolepsy.^[9]

Alleles

See also

• Major histocompatibility complex
• Human leukocyte antigen
• HLA-DQ

References

PDB Gallery 1jk8: Crystal structure of a human insulin peptide-HLA-DQ8 complex   1s9v: Crystal structure of HLA-DQ2 complexed with deamidated gliadin peptide