HLA-DM

major histocompatibility complex, class II, DM alpha
Crystallographic structure of human HLA-DM.[1]
Identifiers
Symbol	HLA-DMA
NCBI gene	3108
HGNC	4934
OMIM	142855
RefSeq	NM_006120
UniProt	P28067
Other data
Locus	Chr. 6 p21.3
Search for Structures Swiss-model Domains InterPro

HLA-DM (human leukocyte antigen DM) is an intracellular protein involved in the mechanism of antigen presentation on antigen presenting cells (APCs) of the immune system.^[2] It does this by assisting in peptide loading of major histocompatibility complex (MHC) class II membrane-bound proteins.^[3] HLA-DM is encoded by the genes HLA-DMA and HLA-DMB.^[4]

HLA-DM is a molecular chaperone^[5] that works in lysosomes and endosomes in cells of the immune system. It works in APCs like macrophages, dendritic cells, and B cells^[6] by interacting with MHC class II molecules.^[7] HLA-DM protects the MHC class II molecules from breaking down, and regulates which proteins or peptides bind to them as well.^[5] This regulates how and when a peptide acts as an antigen initiating an immune response. Thus, HLA-DM is necessary for the immune system to respond effectively to a foreign invader. Impairment in HLA-DM function can result in immunodeficiency and autoimmune diseases.^[8]