Beta-2-Microglobulin (b2M)

BMG; B2MG

SPN	W498
HGNC	914
MGI	88127
PubMed	19708985
RGD	2189
UniProt	P61769
Wiki	B2M

β2 microglobulin lies lateral to the α3 chain on the cell surface. Unlike α3, β2 has no transmembrane region. Directly above β2 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.

An additional function is association with the HFE protein, together regulating the expression of hepcidin in the liver which targets the iron transporter ferroportin on the cytoplasmic membrane of enterocytes and macrophages for degradation resulting in decreased iron uptake from food and iron release from recycled red blood cells respectively. Loss of this function causes iron excess and hemochromatosis.

 

Reference

"The human beta 2-microglobulin gene. Primary structure and definition of the transcriptional unit."
J. Immunol. 139:3132-3138(1987) [PubMed] [Europe PMC] [Abstract]

"Cloning of human beta-microglobulin gene and its high expression in Escherichia coli."
Sheng Wu Gong Cheng Xue Bao 20:99-103(2004) [PubMed] [Europe PMC] [Abstract]

"Complete sequencing and characterization of 21,243 full-length human cDNAs."
Nat. Genet. 36:40-45(2004) [PubMed] [Europe PMC] [Abstract]

"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
Genome Res. 14:2121-2127(2004) [PubMed] [Europe PMC] [Abstract]

"The beta-2-microglobulin mRNA in human Daudi cells has a mutated initiation codon but is still inducible by interferon."
EMBO J. 2:239-243(1983) [PubMed] [Europe PMC] [Abstract]

"Use of synthetic oligonucleotides as hybridization probes: isolation of cloned cDNA sequences for human beta 2-microglobulin."
Proc. Natl. Acad. Sci. U.S.A. 78:6613-6617(1981) [PubMed] [Europe PMC] [Abstract]

"The complete amino acid sequence of beta 2-microglobulin."
Biochemistry 12:4811-4822(1973) [PubMed] [Europe PMC] [Abstract]

"Polymerization of intact beta 2-microglobulin in tissue causes amyloidosis in patients on chronic hemodialysis."
Proc. Natl. Acad. Sci. U.S.A. 83:7908-7912(1986) [PubMed] [Europe PMC] [Abstract]

"Isolation of a granulocyte inhibitory protein from uraemic patients with homology of beta 2-microglobulin."
Nephrol. Dial. Transplant. 9:382-388(1994) [PubMed] [Europe PMC] [Abstract]

"Biochemical characterization of serum and urinary beta 2 microglobulin in end-stage renal disease patients."
Nephrol. Dial. Transplant. 7:1106-1110(1992) [PubMed] [Europe PMC] [Abstract]

"Amino acid sequence of a modified beta 2-microglobulin in renal failure patient urine and long-term dialysis patient blood."
Clin. Chim. Acta 236:135-144(1995) [PubMed] [Europe PMC] [Abstract]

"Glycation of human beta 2-microglobulin in patients with hemodialysis-associated amyloidosis: identification of the glycated sites."
Biochemistry 33:12215-12221(1994) [PubMed] [Europe PMC] [Abstract]

"Initial characterization of the human central proteome."
BMC Syst. Biol. 5:17-17(2011) [PubMed] [Europe PMC] [Abstract]

"An enzyme assisted RP-RPLC approach for in-depth analysis of human liver phosphoproteome."
J. Proteomics 96:253-262(2014) [PubMed] [Europe PMC] [Abstract]

"Structure of the human class I histocompatibility antigen, HLA-A2."
Nature 329:506-512(1987) [PubMed] [Europe PMC] [Abstract]

"Refined structure of the human histocompatibility antigen HLA-A2 at 2.6-A resolution."
J. Mol. Biol. 219:277-319(1991) [PubMed] [Europe PMC] [Abstract]

"1H NMR assignments and secondary structure of human beta 2-microglobulin in solution."
Biochemistry 31:8906-8915(1992) [PubMed] [Europe PMC] [Abstract]

"The three-dimensional structure of a class I major histocompatibility complex molecule missing the alpha 3 domain of the heavy chain."
Proc. Natl. Acad. Sci. U.S.A. 92:1218-1221(1995) [PubMed] [Europe PMC] [Abstract]

"Bound water structure and polymorphic amino acids act together to allow the binding of different peptides to MHC class I HLA-B53."
Immunity 4:215-228(1996) [PubMed] [Europe PMC] [Abstract]

"Crystal structure of monomeric human beta-2-microglobulin reveals clues to its amyloidogenic properties."
Proc. Natl. Acad. Sci. U.S.A. 99:9771-9776(2002) [PubMed] [Europe PMC] [Abstract]

"A structural basis for immunodominant human T cell receptor recognition."
Nat. Immunol. 4:657-663(2003) [PubMed] [Europe PMC] [Abstract]

"Conformation of amyloid fibrils of beta2-microglobulin probed by tryptophan mutagenesis."
J. Biol. Chem. 281:31061-31069(2006) [PubMed] [Europe PMC] [Abstract]

"A native to amyloidogenic transition regulated by a backbone trigger."
Nat. Struct. Mol. Biol. 13:202-208(2006) [PubMed] [Europe PMC] [Abstract]

"High-resolution crystal structure of beta2-microglobulin formed at pH 7.0."
J. Biochem. 142:413-419(2007) [PubMed] [Europe PMC] [Abstract]

"DE loop mutations affect beta2-microglobulin stability and amyloid aggregation."
Biochem. Biophys. Res. Commun. 377:146-150(2008) [PubMed] [Europe PMC] [Abstract]

"The controlling roles of Trp60 and Trp95 in beta2-microglobulin function, folding and amyloid aggregation properties."
J. Mol. Biol. 378:887-897(2008) [PubMed] [Europe PMC] [Abstract]

"Human beta-2 microglobulin W60V mutant structure: Implications for stability and amyloid aggregation."
Biochem. Biophys. Res. Commun. 380:543-547(2009) [PubMed] [Europe PMC] [Abstract]

"Familial hypercatabolic hypoproteinemia caused by deficiency of the neonatal Fc receptor, FcRn, due to a mutant beta2-microglobulin gene."
Proc. Natl. Acad. Sci. U.S.A. 103:5084-5089(2006) [PubMed] [Europe PMC] [Abstract]