immunoglobulin mu chain (Ig-mu, IGHM)

Function

• IgM antibodies play an important role in primary defense mechanisms
• role in early recognition of external invaders like bacteria & viruses, cellular waste & modified self, as well as in recognition & elimination of precancerous & cancerous lesions.
• the membrane-bound form is found in the majority of normal B cells alongside with IgD
• membrane-bound IgM induces the phosphorylation of CD79A & CD79B by the Src family of protein tyrosine kinases
• membrane-bound IgM is non-covalently associated with heterodimer of CD79A & CD79B
• it may cause death of cells by apoptosis
• it is also found in soluble form, representing ~30% of the total serum immunoglobulins where it is found almost exclusively as a homopentamer
• after the antigen binds to the B cell receptor, the secreted form is secreted in large amounts

Laboratory

• cytoplasmic Ig mu cells in blood

More general terms

• immunoglobulin heavy chain

Component of

• immunoglobulin-M (IgM)

Database

• UniProt: http://www.uniprot.org/uniprot/P0DOX6.html
• UniProt: http://www.uniprot.org/uniprot/P01871.html
• OMIM: https://mirror.omim.org/entry/147020