Human Gene HLA-DQB2 (ENST00000411527.5) from GENCODE V44
Description: Homo sapiens major histocompatibility complex, class II, DQ beta 2 (HLA-DQB2), transcript variant 2, mRNA. (from RefSeq NM_001198858) RefSeq Summary (NM_001198858): HLA-DQB2 belongs to the family of HLA class II beta chain paralogs. Class II molecules are heterodimers consisting of an alpha (DQA) and a beta chain (DQB), both anchored in the membrane. They play 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). Polymorphisms in the alpha and beta chains specify the peptide binding specificity, and typing for these polymorphisms is routinely done for bone marrow transplantation. However this gene, HLA-DQB2, is not routinely typed, as it is not thought to have an effect on transplantation. There is conflicting evidence in the literature and public sequence databases for the protein-coding capacity of HLA-DQB2. Because there is evidence of transcription and an intact ORF, HLA-DQB2 is represented in Entrez Gene and in RefSeq as a protein-coding locus. [provided by RefSeq, Oct 2010]. Gencode Transcript: ENST00000411527.5 Gencode Gene: ENSG00000232629.9 Transcript (Including UTRs) Position: hg38 chr6:32,756,098-32,763,490 Size: 7,393 Total Exon Count: 5 Strand: - Coding Region Position: hg38 chr6:32,756,453-32,763,470 Size: 7,018 Coding Exon Count: 5
ID:DQB2_HUMAN DESCRIPTION: RecName: Full=HLA class II histocompatibility antigen, DQ beta 2 chain; AltName: Full=HLA class II histocompatibility antigen, DX beta chain; AltName: Full=MHC class II antigen DQB2; Flags: Precursor; FUNCTION: Binds peptides derived from antigens that access the endocytic route of antigen presenting cells (APC) and presents them on the cell surface for recognition by the CD4 T-cells. The peptide binding cleft accommodates peptides of 10-30 residues. The peptides presented by MHC class II molecules are generated mostly by degradation of proteins that access the endocytic route, where they are processed by lysosomal proteases and other hydrolases. Exogenous antigens that have been endocytosed by the APC are thus readily available for presentation via MHC II molecules, and for this reason this antigen presentation pathway is usually referred to as exogenous. As membrane proteins on their way to degradation in lysosomes as part of their normal turn-over are also contained in the endosomal/lysosomal compartments, exogenous antigens must compete with those derived from endogenous components. Autophagy is also a source of endogenous peptides, autophagosomes constitutively fuse with MHC class II loading compartments. In addition to APCs, other cells of the gastrointestinal tract, such as epithelial cells, express MHC class II molecules and CD74 and act as APCs, which is an unusual trait of the GI tract. To produce a MHC class II molecule that presents an antigen, three MHC class II molecules (heterodimers of an alpha and a beta chain) associate with a CD74 trimer in the ER to form a heterononamer. Soon after the entry of this complex into the endosomal/lysosomal system where antigen processing occurs, CD74 undergoes a sequential degradation by various proteases, including CTSS and CTSL, leaving a small fragment termed CLIP (class-II-associated invariant chain peptide). The removal of CLIP is facilitated by HLA-DM via direct binding to the alpha-beta-CLIP complex so that CLIP is released. HLA-DM stabilizes MHC class II molecules until primary high affinity antigenic peptides are bound. The MHC II molecule bound to a peptide is then transported to the cell membrane surface. In B-cells, the interaction between HLA-DM and MHC class II molecules is regulated by HLA-DO. Primary dendritic cells (DCs) also to express HLA-DO. Lysosomal miroenvironment has been implicated in the regulation of antigen loading into MHC II molecules, increased acidification produces increased proteolysis and efficient peptide loading. SUBUNIT: Heterodimer of an alpha and a beta subunit; also referred as MHC class II molecule. In the endoplasmic reticulum (ER) it forms a heterononamer; 3 MHC class II molecules bind to a CD74 homotrimer (also known as invariant chain or HLA class II histocompatibility antigen gamma chain). In the endosomal/lysosomal system; CD74 undergoes sequential degradation by various proteases; leaving a small fragment termed CLIP on each MHC class II molecule. MHC class II molecule interacts with HLA_DM, and HLA_DO in B-cells, in order to release CLIP and facilitate the binding of antigenic peptides. SUBCELLULAR LOCATION: Cell membrane; Single-pass type I membrane protein. Endoplasmic reticulum membrane; Single-pass type I membrane protein. Golgi apparatus, trans-Golgi network membrane; Single-pass type I membrane protein. Endosome membrane; Single- pass type I membrane protein. Lysosome membrane; Single-pass type I membrane protein. Note=The MHC class II complex transits through a number of intracellular compartments in the endocytic pathway until it reaches the cell membrane for antigen presentation. SIMILARITY: Belongs to the MHC class II family. SIMILARITY: Contains 1 Ig-like C1-type (immunoglobulin-like) domain. CAUTION: This gene appears not to be expressed. SEQUENCE CAUTION: Sequence=CAA60790.1; Type=Erroneous initiation; Note=Translation N-terminally extended;
The RNAfold program from the Vienna RNA Package is used to perform the secondary structure predictions and folding calculations. The estimated folding energy is in kcal/mol. The more negative the energy, the more secondary structure the RNA is likely to have.
Pfam Domains: PF07654 - Immunoglobulin C1-set domain PF00969 - Class II histocompatibility antigen, beta domain
ModBase Predicted Comparative 3D Structure on P05538
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Orthologous Genes in Other Species
Orthologies between human, mouse, and rat are computed by taking the best BLASTP hit, and filtering out non-syntenic hits. For more distant species reciprocal-best BLASTP hits are used. Note that the absence of an ortholog in the table below may reflect incomplete annotations in the other species rather than a true absence of the orthologous gene.
Gene Ontology (GO) Annotations with Structured Vocabulary
Molecular Function: GO:0032395 MHC class II receptor activity
Biological Process: GO:0002376 immune system process GO:0002504 antigen processing and presentation of peptide or polysaccharide antigen via MHC class II GO:0006955 immune response GO:0019882 antigen processing and presentation GO:0019886 antigen processing and presentation of exogenous peptide antigen via MHC class II GO:0050852 T cell receptor signaling pathway GO:0060333 interferon-gamma-mediated signaling pathway
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