Beta-2-Microglobulin (IPR015707)

Short name: B2Microglobulin

Overlapping homologous superfamilies

Family relationships



Beta-2-microglobulin (Beta2m) constitutes the 12kDa light chain of the class I major histocompatibility complex (MHC-I) on the surface of many cells, to which it is non-covalently associated. It is also found in the serum in a free form. Beta-2-microglobulin co-association with the MHC class I heavy chain is prerequisite for functional expression of the protein complex on the cell surface. Together these function in the presentation of nine amino acid peptides to the T-cell receptor of CD8-bearing T lymphocytes and killer inhibitory receptors on natural killer cells.

Beta2m contains a beta-sandwich domain composed of two facing beta-sheets (four stranded and three stranded), that is typical of the C-type immunoglobulin superfamily. This structure is stabilized by an intramolecular disulfide bridge connecting two Cys residues in the facing beta -sheets [PMID: 14595439].

GO terms

Biological Process

GO:0006955 immune response

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0042612 MHC class I protein complex

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.