Important modulator in the HLA class II restricted antigen presentation pathway by interaction with the HLA-DM molecule in B-cells. Modifies peptide exchange activity of HLA-DM.
Combining with an MHC class II protein complex and transmitting the signal from one side of the membrane to the other to initiate a change in cell activity.
The HLA-D region of the human major histocompatibility complex encodes the genes for the alpha and beta chains of the DP, DQ and DR class II antigens. A cDNA clone encoding a new class II beta chain (designated DO) was isolated from a library constructed from mRNA of a mutant B-cell line having a single HLA haplotype. Complete cDNA clones encoding the four isotypic beta chains of the DR1, DQw1, DPw2 and putative DO antigens were sequenced. The DO beta gene was mapped in the D region by hybridization with DNA of HLA-deletion mutants. DO beta mRNA expression is low in B-cell lines but remains in mutant lines which have lost expression of other class II genes. Unlike other class II genes DO beta is not induced by gamma-interferon in fibroblast lines. The DO beta gene is distinct from the DP beta, DQ beta and DR beta genes in its pattern of nucleotide divergence. The independent evolution and expression of DO beta suggest that it may be part of a functionally distinct class II molecule.
Protein involved in immunity, any immune system process that functions in the response of an organism to a potential internal or invasive threat. The vertebrate immune system is formed by the innate immune system (composed of phagocytes, complement, antimicrobial peptides, etc) and by the adaptive immune system which consists of T- and B- lymphocytes.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.