Immunoglobulin heavy constant alpha 2 (IGHA2)
The protein contains 340 amino acids for an estimated molecular weight of 36591 Da.
Constant region of immunoglobulin heavy chains. 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:17576170, PubMed:20176268). Ig alpha is the major immunoglobulin class in body secretions (PubMed:2241915). (updated: Oct. 10, 2018)
Protein identification was indicated in the following studies:
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
This protein is annotated as membranous in UniProt.
(right-click above to access to more options from the contextual menu)
No binding partner found
Biological Process
Antibacterial humoral response
B cell receptor signaling pathway
Complement activation, classical pathway
Defense response to bacterium
Glomerular filtration
Immune response
Innate immune response
Leukocyte migration
Phagocytosis, engulfment
Phagocytosis, recognition
Positive regulation of B cell activation
Positive regulation of respiratory burst
Receptor-mediated endocytosis
Retina homeostasis
The reference OMIM entry for this protein is 147000
Iga constant heavy chain 2; igha2
Immunoglobulin am2
Kunkel et al. (1969) defined a system they called Am(2). The Am(2) and Gm systems, involving IgA and IgG, respectively, appear to be closely linked in man. Gamma A and gamma G markers are closely linked in the mouse also. The system of Vyas and Fudenberg (1969) is not linked to Gm. Van Loghem et al. (1970) showed that the Gm and Am(2) loci are closely linked but Gm and Inv unlinked. Both Am(1) and Am(2) are markers of IgA(2); there are, however, 2 functional genes coding the constant region of IgA. See Curtain et al. (1972). Ordering of the immunoglobulin heavy chain genes was discussed by Flanagan and Rabbitts (1982), who described 2 groups of cosmid clones that seemed to encompass gamma-3/gamma-1/psi-epsilon-1/alpha-1 (region A) and gamma-2/gamma 4/epsilon/alpha-2 (region B). Lefranc et al. (1982) found that immunoglobulins were confined to IgM, IgD, IgG3, IgE and IgA2 in a healthy Tunisian person and in 2 Tunisian brothers apparently unrelated to the first case. The results of Southern hybridization suggested deletion of the gamma-1, gamma-2 and gamma-4 genes, a pseudoepsilon gene and the alpha-1 gene. The probable order of the groups of cosmid clones is 5-prime region A to region B 3-prime, as the deletion presumably starts downstream of gamma-3 (in region A) and ends upstream of the active epsilon gene. Lefranc and Rabbitts (1984) showed that the IgA2 allotypes determined serologically have their counterparts in restriction fragment length polymorphism. Data on gene frequencies of allelic variants were tabulated by Roychoudhury and Nei (1988). ... More on the omim web site
Oct. 20, 2018: Protein entry updated
Automatic update: OMIM entry 147000 was added.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).