HLA-DMB
Major Histocompatibility Complex, Class II, DM Beta Chain
Gene Information Card
| Symbol | HLA-DMB |
|---|---|
| Full Name | Major Histocompatibility Complex, Class II, DM Beta |
| Gene Type | Protein coding |
| Chromosomal Location | 6p21.32 |
| NCBI Gene ID | 3109 ncbi.nlm.nih.gov/gene/3109 |
| Ensembl ID | ENSG00000242574 |
| UniProt ID | P28068 |
| OMIM ID | 142856 |
| HGNC ID | 4930 |
| Aliases | DMB, HLA-DMB, HLA-DM beta chain |
Description
HLA-DMB encodes the beta chain of the HLA-DM heterodimer, a non-classical MHC class II molecule. HLA-DM is localized in endosomal/lysosomal compartments and catalyzes the exchange of class II-associated invariant chain peptide (CLIP) with antigenic peptides for loading onto classical MHC class II molecules (HLA-DR, -DQ, -DP). This process is critical for CD4+ T-cell activation and adaptive immune responses.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Bare Lymphocyte Syndrome Type II (BLS II) | Loss-of-function mutations in HLA-DMB impair peptide loading, leading to deficient MHC class II surface expression and severe combined immunodeficiency. | OMIM #209920; ClinVar |
| Rheumatoid Arthritis | Polymorphisms in HLA-DMB are associated with altered antigen presentation and autoimmune susceptibility. | GWAS catalog; NCBI |
| Type 1 Diabetes | HLA-DMB variants may influence autoantigen presentation and disease risk. | OMIM #222100; literature |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Lymph node | 12.5 | High |
| Spleen | 11.8 | High |
| Tonsil | 10.9 | High |
| Bone marrow | 6.2 | Medium |
| Lung | 4.1 | Medium |
| Liver | 0.8 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| B-lymphocyte (GM12878) | 15.3 | High expression |
| Monocyte (THP-1) | 10.1 | High expression |
| Dendritic cell (immature) | 12.7 | High expression |
| HeLa | 0.5 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.533G>A (p.Arg178His) | Missense | <0.01% | Impaired peptide loading; associated with BLS II |
| c.1A>G (p.Met1Val) | Start loss | <0.01% | Loss of protein expression; BLS II |
| c.IVS1+1G>A | Splice donor | <0.01% | Skipping of exon 2; loss of function |
Mutation functional classification
Loss of Function (LOF)
Homozygous or compound heterozygous mutations (e.g., missense, nonsense, splice-site) cause complete loss of HLA-DM function, leading to BLS II.
Gain of Function (GOF)
Not reported.
Dominant Negative (DN)
Not reported; HLA-DMB mutations are typically recessive.
View complete mutation data：
Gene Ontology (GO)
Pathways
• Antigen processing and presentation (KEGG hsa04612)
• Endosomal/Vacuolar pathway (Reactome R-HSA-2132295)
Protein Summary
HLA-DMB is a 263-amino acid transmembrane glycoprotein that forms the beta chain of the HLA-DM heterodimer. It contains an Ig-like C1-type domain and is essential for catalyzing CLIP release and peptide loading onto MHC class II molecules. The protein is predominantly expressed in antigen-presenting cells (B cells, dendritic cells, macrophages) and localizes to late endosomes and lysosomes.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| HLA-DMB Knockout HEK293 Cell Line | EDJ-KQ50347 | Human | 3109 | Details Get a Quote |
| HLA-DMB Knockout HeLa Cell Line | EDJ-KQ53518 | Human | 3109 | Details Get a Quote |
| HLA-DMB Knockout A-549 Cell Line | EDJ-KQ61987 | Human | 3109 | Details Get a Quote |
| HLA-DMB Knockout HCT 116 Cell Line | EDJ-KQ70469 | Human | 3109 | Details Get a Quote |
