B2M/Beta-2-microglobulin Protein, Human (HEK293, His)

B2M, or Beta-2-microglobulin, functions as a critical component of the class I major histocompatibility complex (MHC), playing a central role in presenting peptide antigens to the immune system. Notably, exogenously applied M. tuberculosis EsxA or EsxA-EsxB binds B2M and reduces its export to the cell surface, potentially leading to defects in class I antigen presentation. B2M exists as a heterodimer, composed of an alpha chain and a beta chain, with the latter serving as the beta-chain of major histocompatibility complex class I molecules. Polymers of B2M have been observed in tissues of patients on long-term hemodialysis. B2M, in its isolated form, interacts with M. tuberculosis EsxA and an EsxA-EsxB complex, forming a tripartite complex detectable in the host endoplasmic reticulum. The stability of the B2M-EsxA complex extends across a broad pH range and in the presence of high salt concentrations. Additionally, B2M forms heterotrimers with HLA-E, HLA-G, and HLA-F, along with a self- or foreign peptide, contributing to the diverse functions of the major histocompatibility complex. Furthermore, B2M engages in a heterotrimeric complex with MR1, playing a role in antigen presentation associated with metabolite antigens.