HLA-DPB1
HLA-DPB1 (major histocompatibility complex, class II, DP beta 1; also HLA-DP1B) encodes the beta chain of the HLA-DP class II heterodimer. Together with the DP alpha chain, it binds peptides from antigens in the endocytic route and presents them to CD4 T-cells. Browse Assay Genie's current range of HLA-DPB1 research reagents below, or read on for the biology behind the target.
HLA-DPB1 is the beta chain of the HLA-DP molecule, an MHC class II heterodimer made of an alpha chain (DPA) and a beta chain (DPB), both anchored in the membrane. The molecule binds peptides derived from antigens that enter the endocytic route of antigen presenting cells and displays them at the cell surface for recognition by CD4 T-cells. Its peptide-binding cleft accommodates peptides of 10-30 residues. These peptides are generated mostly by lysosomal proteases and other hydrolases acting on proteins that reach the endosomal and lysosomal compartments. Exogenous antigens must compete with endogenous material, including membrane proteins in turnover and peptides supplied by autophagy.
To form a peptide-presenting molecule, class II heterodimers associate with a CD74 trimer in the endoplasmic reticulum. After the complex enters the endosomal and lysosomal system, proteases including CTSS and CTSL degrade CD74 and leave a small fragment, CLIP. HLA-DM binds the alpha-beta-CLIP complex, releases CLIP and stabilises the class II molecule until a high-affinity peptide is bound. The loaded molecule then moves to the cell surface. In B-cells, HLA-DM activity is regulated by HLA-DO. UniProt lists the HLA-DPB1 protein at the cell membrane and in the endoplasmic reticulum, trans-Golgi network, endosome and lysosome membranes.
The HLA-DPB1 gene belongs to the HLA class II beta chain paralogues and to the histocompatibility complex gene group. Class II molecules are expressed in antigen presenting cells such as B lymphocytes, dendritic cells and macrophages, and cells of the gastrointestinal tract, including epithelial cells, can also act as antigen presenting cells. The gene has six exons: exon one encodes the leader peptide, exons two and three the extracellular domains, exon four the transmembrane domain and exon five the cytoplasmic tail. Both the alpha and beta chains of DP carry polymorphisms that specify peptide-binding preferences, giving up to four different molecules.
HLA-DPB1 is a core component of the exogenous MHC class II pathway that presents endocytosed antigen-derived peptides to CD4 T-cells.
Studies of CD74, CLIP removal by HLA-DM and HLA-DO regulation use class II chains such as HLA-DPB1 to follow peptide loading.
The protein is found in endoplasmic reticulum, Golgi, endosome and lysosome membranes, making it relevant to class II transport and loading compartments.
Polymorphisms in the DP alpha and beta chains specify peptide-binding specificity, which makes HLA-DPB1 a focus for immunogenetic analysis.
HLA-DPB1 encodes the beta chain of the HLA-DP class II molecule. Paired with the alpha chain, it binds peptides of 10-30 residues derived from antigens in the endocytic route and presents them at the cell surface to CD4 T-cells.
The HGNC name is major histocompatibility complex, class II, DP beta 1, and the alias is HLA-DP1B. UniProt calls the product HLA class II histocompatibility antigen, DP beta 1 chain. NCBI Gene also refers to it as HLA-DPB, a class II beta chain paralogue.
Class II molecules are expressed in antigen presenting cells, including B lymphocytes, dendritic cells and macrophages. Both DP chains carry polymorphisms that specify peptide-binding preferences. Check the datasheet of any product for its validated reactivity.
Other HLA class II chains and related MHC class I molecules involved in antigen presentation.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P04440; product specifications from Assay Genie datasheets.