HLA-DMB

HLA-DMB belongs to the HLA class II beta chain paralogues. This class II molecule is a heterodimer consisting of an alpha (DMA) and a beta (DMB) chain, both anchored in the membrane. It is located in intracellular vesicles. DM plays a central role in the peptide loading of MHC class II molecules by helping to release the CLIP (class II-associated invariant chain peptide) molecule from the peptide binding site. Class II molecules are expressed in antigen presenting cells (APC: B lymphocytes, dendritic cells, macrophages). The beta chain is approximately 26-28 kDa and its gene contains 6 exons. Exon one encodes the leader peptide, exons 2 and 3 encode the two extracellular domains, exon 4 encodes the transmembrane domain and exon 5 encodes the cytoplasmic tail. [provided by RefSeq]

Full Name

major histocompatibility complex, class II, DM beta

Function

Plays a critical role in catalyzing the release of class II-associated invariant chain peptide (CLIP) from newly synthesized MHC class II molecules and freeing the peptide binding site for acquisition of antigenic peptides. In B-cells, the interaction between HLA-DM and MHC class II molecules is regulated by HLA-DO.

Biological Process

Adaptive immune response Source: UniProtKB-KW
Antigen processing and presentation of exogenous peptide antigen via MHC class II Source: UniProtKB
MHC class II protein complex assembly Source: UniProtKB
Peptide antigen assembly with MHC class II protein complex Source: UniProtKB
Positive regulation of T cell activation Source: GO_Central
Positive regulation of T cell activation via T cell receptor contact with antigen bound to MHC molecule on antigen presenting cell Source: UniProtKB
Positive regulation of T cell proliferation Source: UniProtKB

Cellular Location

Lysosome membrane; Late endosome membrane. Localizes to late endocytic compartment. Associates with lysosome membranes.

Topology

Lumenal: 19-218
Helical: 219-239
Cytoplasmic: 240-263