- Beta-2 microglobulin
β2 microglobulin also known as B2M is a component of
MHC class I molecules, which are present on almost all cells of the body (red blood cell s are a notable exception).cite web | title = Entrez Gene: Beta-2-microglobulin| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=567| accessdate = ] cite journal | author = Güssow D, Rein R, Ginjaar I, Hochstenbach F, Seemann G, Kottman A, Ploegh HL | title = The human beta 2-microglobulin gene. Primary structure and definition of the transcriptional unit | journal = J. Immunol. | volume = 139 | issue = 9 | pages = 3132–8 | year = 1987 | month = November | pmid = 3312414 | | url = http://www.jimmunol.org/cgi/content/abstract/139/9/3132 | issn = ]tructure and function
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 andQa .Clinical significance
In patients on long-term
hemodialysis , it can aggregate intoamyloid fibers that deposit in joint spaces, a disease known asdialysis-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 andlymphoma .cite web |url=http://www.cancer.gov/templates/db_alpha.aspx?CdrID=411372 |title=Definition of beta-2-microglobulin - NCI Dictionary of Cancer Terms |format= |work= |accessdate=]References
Further reading
PBB_Further_reading
citations =
*cite journal | author=Winchester JF, Salsberg JA, Levin NW |title=Beta-2 microglobulin in ESRD: an in-depth review. |journal=Advances in renal replacement therapy |volume=10 |issue= 4 |pages= 279–309 |year= 2004 |pmid= 14681859 |doi=
*cite journal | author=Krangel MS, Orr HT, Strominger JL |title=Assembly and maturation of HLA-A and HLA-B antigens in vivo. |journal=Cell |volume=18 |issue= 4 |pages= 979–91 |year= 1980 |pmid= 93026 |doi=
*cite journal | author=Okon M, Bray P, Vucelić D |title=1H NMR assignments and secondary structure of human beta 2-microglobulin in solution. |journal=Biochemistry |volume=31 |issue= 37 |pages= 8906–15 |year= 1992 |pmid= 1390678 |doi=
*cite journal | author=Guo HC, Jardetzky TS, Garrett TP, "et al." |title=Different length peptides bind to HLA-Aw68 similarly at their ends but bulge out in the middle. |journal=Nature |volume=360 |issue= 6402 |pages= 364–6 |year= 1992 |pmid= 1448153 |doi= 10.1038/360364a0
*cite journal | author=Gattoni-Celli S, Kirsch K, Timpane R, Isselbacher KJ |title=Beta 2-microglobulin gene is mutated in a human colon cancer cell line (HCT) deficient in the expression of HLA class I antigens on the cell surface. |journal=Cancer Res. |volume=52 |issue= 5 |pages= 1201–4 |year= 1992 |pmid= 1737380 |doi=
*cite journal | author=Saper MA, Bjorkman PJ, Wiley DC |title=Refined structure of the human histocompatibility antigen HLA-A2 at 2.6 A resolution. |journal=J. Mol. Biol. |volume=219 |issue= 2 |pages= 277–319 |year= 1991 |pmid= 2038058 |doi=
*cite journal | author=Caruana RJ, Lobel SA, Leffell MS, "et al." |title=Tumor necrosis factor, interleukin-1 and beta 2-microglobulin levels in chronic hemodialysis patients. |journal=The International journal of artificial organs |volume=13 |issue= 12 |pages= 794–8 |year= 1991 |pmid= 2289831 |doi=
*cite journal | author=Connors LH, Shirahama T, Skinner M, "et al." |title=In vitro formation of amyloid fibrils from intact beta 2-microglobulin. |journal=Biochem. Biophys. Res. Commun. |volume=131 |issue= 3 |pages= 1063–8 |year= 1985 |pmid= 2413854 |doi=
*cite journal | author=Hochman JH, Shimizu Y, DeMars R, Edidin M |title=Specific associations of fluorescent beta-2-microglobulin with cell surfaces. The affinity of different H-2 and HLA antigens for beta-2-microglobulin. |journal=J. Immunol. |volume=140 |issue= 7 |pages= 2322–9 |year= 1988 |pmid= 2450918 |doi=
*cite journal | author=Homma N, Gejyo F, Isemura M, Arakawa M |title=Collagen-binding affinity of beta-2-microglobulin, a preprotein of hemodialysis-associated amyloidosis. |journal=Nephron |volume=53 |issue= 1 |pages= 37–40 |year= 1989 |pmid= 2674742 |doi=
*cite journal | author=Bataille R, Grenier J, Commes T |title=In vitro production of beta 2 microglobulin by human myeloma cells. |journal=Cancer Invest. |volume=6 |issue= 3 |pages= 271–7 |year= 1988 |pmid= 3048575 |doi=
*cite journal | author=Hönig R, Marsen T, Schad S, "et al." |title=Correlation of beta-2-microglobulin concentration changes to changes of distribution volume. |journal=The International journal of artificial organs |volume=11 |issue= 6 |pages= 459–64 |year= 1989 |pmid= 3060434 |doi=
*cite journal | author=Bjorkman PJ, Saper MA, Samraoui B, "et al." |title=Structure of the human class I histocompatibility antigen, HLA-A2. |journal=Nature |volume=329 |issue= 6139 |pages= 506–12 |year= 1987 |pmid= 3309677 |doi= 10.1038/329506a0
*cite journal | author=Güssow D, Rein R, Ginjaar I, "et al." |title=The human beta 2-microglobulin gene. Primary structure and definition of the transcriptional unit. |journal=J. Immunol. |volume=139 |issue= 9 |pages= 3132–8 |year= 1987 |pmid= 3312414 |doi=
*cite journal | author=Cunningham BA, Wang JL, Berggård I, Peterson PA |title=The complete amino acid sequence of beta 2-microglobulin. |journal=Biochemistry |volume=12 |issue= 24 |pages= 4811–22 |year= 1974 |pmid= 4586824 |doi=
*cite journal | author=Suggs SV, Wallace RB, Hirose T, "et al." |title=Use of synthetic oligonucleotides as hybridization probes: isolation of cloned cDNA sequences for human beta 2-microglobulin. |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=78 |issue= 11 |pages= 6613–7 |year= 1982 |pmid= 6171820 |doi=
*cite journal | author=Momoi T, Suzuki M, Titani K, "et al." |title=Amino acid sequence of a modified beta 2-microglobulin in renal failure patient urine and long-term dialysis patient blood. |journal=Clin. Chim. Acta |volume=236 |issue= 2 |pages= 135–44 |year= 1995 |pmid= 7554280 |doi=
*cite journal | author=Collins EJ, Garboczi DN, Karpusas MN, Wiley DC |title=The three-dimensional structure of a class I major histocompatibility complex molecule missing the alpha 3 domain of the heavy chain. |journal=Proc. Natl. Acad. Sci. U.S.A. |volume=92 |issue= 4 |pages= 1218–21 |year= 1995 |pmid= 7862664 |doi=
*cite journal | author=Matoba R, Okubo K, Hori N, "et al." |title=The addition of 5'-coding information to a 3'-directed cDNA library improves analysis of gene expression. |journal=Gene |volume=146 |issue= 2 |pages= 199–207 |year= 1994 |pmid= 8076819 |doi=
*cite journal | author=Wang Z, Cao Y, Albino AP, "et al." |title=Lack of HLA class I antigen expression by melanoma cells SK-MEL-33 caused by a reading frameshift in beta 2-microglobulin messenger RNA. |journal=J. Clin. Invest. |volume=91 |issue= 2 |pages= 684–92 |year= 1993 |pmid= 8432869 |doi=External links
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