HLA-DQB2
HLA-DQB2 (major histocompatibility complex, class II, DQ beta 2, also known as HLA-DXB) encodes an MHC class II beta chain paralog. Paired with an alpha chain, it forms a membrane-anchored heterodimer that belongs to the antigen-presentation machinery of the immune system. Browse Assay Genie's current range of HLA-DQB2 research reagents below, or read on for the biology behind the target.
MHC class II molecules bind peptides derived from antigens that enter the endocytic route of antigen presenting cells (APCs) and present them on the cell surface for recognition by CD4 T-cells. The peptide binding cleft accommodates peptides of 10-30 residues. These peptides are generated mostly by degradation of proteins in the endocytic route, where lysosomal proteases and other hydrolases process them. Exogenous antigens must compete with peptides from endogenous components, including membrane proteins turning over in lysosomes and material supplied by autophagy.
To build a presenting molecule, three MHC class II heterodimers, each made of an alpha and a beta chain, associate with a CD74 trimer in the endoplasmic reticulum. After the complex enters the endosomal/lysosomal system, proteases including CTSS and CTSL degrade CD74 and leave the CLIP fragment. HLA-DM binds the alpha-beta-CLIP complex, helps release CLIP and stabilises the molecule until a high-affinity peptide is bound. The peptide-loaded molecule then travels to the cell surface. In B-cells, HLA-DO regulates the HLA-DM interaction.
The HLA-DQB2 gene belongs to the family of HLA class II beta chain paralogs, in the histocompatibility complex and C1-set domain containing gene groups. Class II molecules are expressed in APCs such as B lymphocytes, dendritic cells and macrophages. Polymorphisms in alpha and beta chains specify peptide binding specificity. HLA-DQB2 is not routinely typed for transplantation, as it is not thought to affect outcome. The literature and sequence databases conflict on its protein-coding capacity, but transcription and an intact ORF support its representation in Entrez Gene and RefSeq as a protein-coding locus.
HLA-DQB2 belongs to the MHC class II machinery that presents peptides from endocytosed antigens to CD4 T-cells.
As a class II beta chain paralog, it supports comparison with other DQ and HLA class II genes.
Class II loading involves CD74, CLIP removal by HLA-DM and endosomal or lysosomal proteolysis, the context in which this beta chain functions.
HLA class II polymorphism is typed for bone marrow transplantation, although HLA-DQB2 is not thought to influence transplant outcome.
HLA-DQB2 encodes a beta chain of the MHC class II family. Class II heterodimers bind peptides from antigens in the endocytic route and present them on the APC surface to CD4 T-cells. Check the datasheet of any product for its validated reactivity.
The gene is also known as HLA-DXB, and its full name is major histocompatibility complex, class II, DQ beta 2. UniProt lists the protein as HLA class II histocompatibility antigen, DQ beta 2 chain.
Evidence is conflicting. Because there is evidence of transcription and an intact ORF, HLA-DQB2 is represented in Entrez Gene and RefSeq as a protein-coding locus. It is not routinely typed for transplantation, as it is not thought to affect it.
Other HLA class II chains, classical and non-classical HLA class I molecules and antigen-presentation targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P05538; product specifications from Assay Genie datasheets.