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Beta-2 microglobulin: Wikis


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PDB rendering based on 1a1m.
Available structures
1a1m, 1a1n, 1a1o, 1a6z, 1a9b, 1a9e, 1agb, 1agc, 1agd, 1age, 1agf, 1akj, 1ao7, 1b0g, 1b0r, 1bd2, 1c16, 1ce6, 1cg9, 1de4, 1duy, 1duz, 1e27, 1e28, 1eey, 1eez, 1efx, 1exu, 1gzp, 1gzq, 1hhg, 1hhh, 1hhi, 1hhj, 1hhk, 1hla, 1hsa, 1hsb, 1i1f, 1i1y, 1i4f, 1i7r, 1i7t, 1i7u, 1im3, 1im9, 1jf1, 1jgd, 1jge, 1jht, 1jnj, 1k5n, 1kpr, 1ktl, 1lds, 1lp9, 1m05, 1m6o, 1mhe, 1mi5, 1n2r, 1of2, 1oga, 1ogt, 1onq, 1p7q, 1py4, 1q94, 1qew, 1qlf, 1qqd, 1qr1, 1qrn, 1qse, 1qsf, 1qvo, 1r3h, 1s8d, 1s9w, 1s9x, 1s9y, 1sys, 1syv, 1t1w, 1t1x, 1t1y, 1t1z, 1t20, 1t21, 1t22, 1tmc, 1tvb, 1tvh, 1uqs, 1uxs, 1uxw, 1vgk, 1w0v, 1w0w, 1w72, 1x7q, 1xh3, 1xr8, 1xr9, 1xz0, 1ydp, 1ypz, 1zhk, 1zhl, 1zs8, 1zsd, 1zt4, 1zvs, 2a83, 2ak4, 2av1, 2av7, 2axf, 2axg, 2bck, 2bnq, 2bnr, 2bsr, 2bss, 2bst, 2bsu, 2bsv, 2bvo, 2bvp, 2bvq, 2c7u, 2cii, 2cik, 2clr, 2d31, 2d4d, 2d4f, 2dyp, 2esv, 2f53, 2f54, 2f74, 2f8o, 2fyy, 2fz3, 2git, 2gj6, 2h26, 2h6p, 2hjk, 2hjl, 2hla, 2hn7, 2nw3, 2nx5, 3hla
Symbols B2M;
External IDs OMIM109700 MGI88127 HomoloGene2987 GeneCards: B2M Gene
RNA expression pattern
PBB GE B2M 201891 s at tn.png
PBB GE B2M 216231 s at tn.png
More reference expression data
Species Human Mouse
Entrez 567 12010
Ensembl ENSG00000166710 ENSMUSG00000060802
UniProt P61769 Q3U679
RefSeq (mRNA) NM_004048 NM_009735
RefSeq (protein) NP_004039 NP_033865
Location (UCSC) Chr 15:
42.79 - 42.8 Mb
Chr 2:
121.84 - 121.84 Mb
PubMed search [1] [2]

β2 microglobulin also known as B2M is a component of MHC class I molecules, which are present on all nucleated cells (but not red blood cells).[1][2]


Structure and function

Schematic representation of MHC class I

β2 microglobulin lies lateral to the α3 chain on the cell surface. Unlike α3, β2 has no transmembrane region. Directly above β2 (i.e. away from the cell) lies the α1 chain, which itself is lateral to the α2.

β2 microglobulin associates not only with the alpha chain of MHC class I molecules, but also with class I-like molecules such as CD1 and Qa.

Clinical significance

In patients on long-term hemodialysis, it can aggregate into amyloid fibers that deposit in joint spaces, a disease known as dialysis-related amyloidosis.

Mice models deficient for the β2 microglobulin gene have been engineered. These mice demonstrate that β2 microglobulin is necessary for cell surface expression of MHC class I and stability of the peptide binding groove. In fact, in the absence of β2 microglobulin, very limited amounts of MHC class I (classical and non-classical) molecules can be detected on the surface. In the absence of MHC class I, CD8 T cells cannot develop. (CD8 T cells are a subset of T cells involved in the development of acquired immunity.)

Levels of beta-2 microglobulin can be elevated in multiple myeloma and lymphoma [3], though in these cases primary amyloidosis (amyloid light chain) and secondary amyloidosis (Amyloid associated protein) are more common.


Further reading

External links

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