B2M

This gene encodes a serum protein found in association with the major histocompatibility complex (MHC) class I heavy chain on the surface of nearly all nucleated cells. The protein has a predominantly beta-pleated sheet structure that can form amyloid fibrils in some pathological conditions. The encoded antimicrobial protein displays antibacterial activity in amniotic fluid. A mutation in this gene has been shown to result in hypercatabolic hypoproteinemia.[provided by RefSeq, Aug 2014]B2M (Beta-2-Microglobulin) is a Protein Coding gene. Diseases associated with B2M include Immunodeficiency 43 and Amyloidosis, Familial Visceral. Among its related pathways are Cytokine Signaling in Immune system and Innate Immune System. Gene Ontology (GO) annotations related to this gene include identical protein binding.Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. Exogenously applied M.tuberculosis EsxA or EsxA-EsxB (or EsxA expressed in host) binds B2M and decreases its export to the cell surface (total protein levels do not change), probably leading to defects in class I antigen presentation (PubMed:25356553).

Beta-2-Microglobulin

Component of the class I major histocompatibility complex (MHC). Involved in the presentation of peptide antigens to the immune system. Exogenously applied M.tuberculosis EsxA or EsxA-EsxB (or EsxA expressed in host) binds B2M and decreases its export to the cell surface (total protein levels do not change), probably leading to defects in class I antigen presentation (PubMed:25356553).

Amyloid fibril formation Source: ARUK-UCL
Antibacterial humoral response Source: UniProtKB
Antigen processing and presentation of endogenous peptide antigen via MHC class I Source: BHF-UCL
Antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent Source: Reactome
Antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-independent Source: Reactome
Antigen processing and presentation of exogenous protein antigen via MHC class Ib, TAP-dependent Source: Ensembl
Antigen processing and presentation of peptide antigen via MHC class I Source: Reactome
Antimicrobial humoral immune response mediated by antimicrobial peptide Source: UniProtKB
Cellular response to iron(III) ion Source: Ensembl
Cellular response to iron ion Source: BHF-UCL
Cellular response to lipopolysaccharide Source: UniProtKB
Cellular response to nicotine Source: ARUK-UCL
Defense response to Gram-negative bacterium Source: UniProtKB
Defense response to Gram-positive bacterium Source: UniProtKB
Innate immune response Source: UniProtKB
Interferon-gamma-mediated signaling pathway Source: Reactome
Iron ion homeostasis Source: BHF-UCL
Iron ion transport Source: Ensembl
Learning or memory Source: ARUK-UCL
Modulation by symbiont of host defense response Source: Reactome
Modulation of age-related behavioral decline Source: ARUK-UCL
Negative regulation of epithelial cell proliferation Source: ARUK-UCL
Negative regulation of forebrain neuron differentiation Source: ARUK-UCL
Negative regulation of neurogenesis Source: ARUK-UCL
Negative regulation of neuron projection development Source: Ensembl
Negative regulation of receptor binding Source: BHF-UCL
Neutrophil degranulation Source: Reactome
Positive regulation of cellular senescence Source: ARUK-UCL
Positive regulation of ferrous iron binding Source: BHF-UCL
Positive regulation of protein binding Source: BHF-UCL
Positive regulation of receptor binding Source: BHF-UCL
Positive regulation of receptor-mediated endocytosis Source: BHF-UCL
Positive regulation of T cell cytokine production Source: BHF-UCL
Positive regulation of T cell mediated cytotoxicity Source: Ensembl
Positive regulation of transferrin receptor binding Source: BHF-UCL
Protein homotetramerization Source: ARUK-UCL
Protein refolding Source: Ensembl
Regulation of defense response to virus by virus Source: Reactome
Regulation of erythrocyte differentiation Source: Ensembl
Regulation of immune response Source: Reactome
Regulation of iron ion transport Source: BHF-UCL
Regulation of membrane depolarization Source: UniProtKB
Response to cadmium ion Source: Ensembl
Response to drug Source: Ensembl
Response to molecule of bacterial origin Source: Ensembl
Retina homeostasis Source: UniProtKB
T cell differentiation in thymus Source: Ensembl

Secreted; Cell surface. Detected in serum and urine (PubMed:1336137, PubMed:7554280). (Microbial infection) In the presence of M.tuberculosis EsxA-EsxB complex decreased amounts of B2M are found on the cell surface (PubMed:25356553).

Immunodeficiency 43 (IMD43): A disorder characterized by marked reduction in serum concentrations of immunoglobulins and albumin, and hypoproteinemia due to hypercatabolism. Patients may suffer from recurrent respiratory tract infections and severe skin disease.
Amyloidosis 8 (AMYL8): The disease is caused by variants affecting the gene represented in this entry. Apart from the presence of causative mutations, beta-2-microglobulin may adopt the fibrillar configuration of amyloid when its serum levels are persistently high. High beta(2)-microglobulin serum levels result in amyloidosis in patients on long-term hemodialysis (PubMed:7918443). In contrast to patients with dialysis-related amyloidosis, patients with hereditary amyloidosis have normal circulating concentrations of beta2-microglobulin (PubMed:22693999). A form of hereditary generalized amyloidosis. Clinical features include extensive visceral amyloid deposits, renal amyloidosis resulting in nephrotic syndrome, arterial hypertension, hepatosplenomegaly, cholestasis, petechial skin rash. There is no involvement of the nervous system.

Glycation of Ile-21 is observed in long-term hemodialysis patients.