| Identification |
|---|
| HMDB Protein ID
| HMDBP12427 |
| Secondary Accession Numbers
| None |
| Name
| Immunoglobulin mu heavy chain |
| Synonyms
|
- Immunoglobulin mu heavy chain OU
|
| Gene Name
| Not Available |
| Protein Type
| Unknown |
| Biological Properties |
|---|
| General Function
| Not Available |
| Specific Function
| Immunoglobulins, also known as antibodies, are membrane-bound or secreted glycoproteins produced by B lymphocytes. In the recognition phase of humoral immunity, the membrane-bound immunoglobulins serve as receptors which, upon binding of a specific antigen, trigger the clonal expansion and differentiation of B lymphocytes into immunoglobulins-secreting plasma cells. Secreted immunoglobulins mediate the effector phase of humoral immunity, which results in the elimination of bound antigens (PubMed:22158414, PubMed:20176268). The antigen binding site is formed by the variable domain of one heavy chain, together with that of its associated light chain. Thus, each immunoglobulin has two antigen binding sites with remarkable affinity for a particular antigen. The variable domains are assembled by a process called V-(D)-J rearrangement and can then be subjected to somatic hypermutations which, after exposure to antigen and selection, allow affinity maturation for a particular antigen (PubMed:20176268, PubMed:17576170). IgM antibodies play an important role in primary defense mechanisms. They have been shown to be involved in early recognition of external invaders like bacteria and viruses, cellular waste and modified self, as well as in recognition and elimination of precancerous and 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 and CD79B by the Src family of protein tyrosine kinases. It may cause death of cells by apoptosis. It is also found in soluble form, which represents about 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 (, PubMed:16895553). |
| Pathways
|
Not Available
|
| Reactions
| Not Available |
| GO Classification
|
| Biological Process |
| adaptive immune response |
| Cellular Component |
| plasma membrane |
| extracellular region |
| immunoglobulin complex |
|
| Cellular Location
|
Not Available
|
| Gene Properties |
|---|
| Chromosome Location
| Not Available |
| Locus
| Not Available |
| SNPs
| Not Available |
| Gene Sequence
|
Not Available
|
| Protein Properties |
|---|
| Number of Residues
| Not Available |
| Molecular Weight
| 63485.405 |
| Theoretical pI
| Not Available |
| Pfam Domain Function
|
|
| Signals
|
Not Available
|
|
Transmembrane Regions
|
Not Available
|
| Protein Sequence
|
Not Available
|
| External Links |
|---|
| GenBank ID Protein
| Not Available |
| UniProtKB/Swiss-Prot ID
| P0DOX6 |
| UniProtKB/Swiss-Prot Entry Name
| IGM_HUMAN |
| PDB IDs
|
Not Available |
| GenBank Gene ID
| Not Available |
| GeneCard ID
| Not Available |
| GenAtlas ID
| Not Available |
| HGNC ID
| Not Available |
| References |
|---|
| General References
| - Putnam FW, Florent G, Paul C, Shinoda T, Shimizu A: Complete amino acid sequence of the Mu heavy chain of a human IgM immunoglobulin. Science. 1973 Oct 19;182(4109):287-91. doi: 10.1126/science.182.4109.287. [PubMed:4742735 ]
- Geisberger R, Lamers M, Achatz G: The riddle of the dual expression of IgM and IgD. Immunology. 2006 Aug;118(4):429-37. doi: 10.1111/j.1365-2567.2006.02386.x. [PubMed:16895553 ]
- Teng G, Papavasiliou FN: Immunoglobulin somatic hypermutation. Annu Rev Genet. 2007;41:107-20. doi: 10.1146/annurev.genet.41.110306.130340. [PubMed:17576170 ]
- Schroeder HW Jr, Cavacini L: Structure and function of immunoglobulins. J Allergy Clin Immunol. 2010 Feb;125(2 Suppl 2):S41-52. doi: 10.1016/j.jaci.2009.09.046. [PubMed:20176268 ]
- McHeyzer-Williams M, Okitsu S, Wang N, McHeyzer-Williams L: Molecular programming of B cell memory. Nat Rev Immunol. 2011 Dec 9;12(1):24-34. doi: 10.1038/nri3128. [PubMed:22158414 ]
|
