Immunoglobulin J chain (IGJ)
The protein contains 159 amino acids for an estimated molecular weight of 18099 Da.
Serves to link two monomer units of either IgM or IgA. In the case of IgM, the J chain-joined dimer is a nucleating unit for the IgM pentamer, and in the case of IgA it induces dimers and/or larger polymers. It also helps to bind these immunoglobulins to secretory component. (updated: Oct. 7, 2020)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
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.
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No binding partner found
Biological Process
Adaptive immune response
Antibacterial humoral response
Glomerular filtration
Humoral immune response
Immune response
Innate immune response
Leukocyte migration
Positive regulation of protein oligomerization
Positive regulation of respiratory burst
Protein-containing complex assembly
Receptor-mediated endocytosis
Retina homeostasis
The reference OMIM entry for this protein is 147790
Immunoglobulin j polypeptide, linker protein for immunoglobulin alpha and mu polypeptides; igj
Igcj
J chain; jch
J chain is a 137-amino acid protein that is synthesized in B lymphocytes and serves 2 known functions: linking immunoglobulin monomers (IgM to pentamers, IgA to dimers) and binding these immunoglobulins to secretory component (Koshland, 1985). Using probes from J chain clones, Max et al. (1986) assigned the J chain gene to 4q21 by Southern analysis of somatic cell hybrids and by in situ hybridization. This band is the site of translocations with chromosome 11 in some acute lymphocytic leukemias. In the mouse, JCH maps to chromosome 5 which carries 4 other genes that are also on human no. 4 (PGM2, PEPS, ALB, and AFP). Max et al. (1986) also discovered genetic variation in the number of repeats of a 27-bp sequence that is tandemly reduplicated 5-prime of the human J chain gene. They suggested that this polymorphism may be 'useful in genetic linkage studies in a region of chromosome 4 heretofore relatively barren of markers definitively localized to a particular subband.' (The J chain gene is not to be confused with the J region gene of immunoglobulins; see 146970, 147010, and 147230 for the J region genes of kappa, heavy, and lambda chains, respectively.) Lim et al. (2006) showed that the CRLZ1 (UTP3; 611614) and IgJ genes are adjacent but divergently transcribed in human and mouse. By chromatin immunoprecipitation and FACS analysis of sorted mouse pre-B cells and plasma cells, they found that IgJ was expressed in the plasma cell stage, whereas Crlz1 was expressed in the pre-B cell stage. The stage-specific expression of IgJ and Crlz1 was regulated by chromatin accessibility and acetylation. DNase I hypersensitive site 1 on the IgJ promoter was opened in plasma cells, but hypersensitive sites 9 and 10 on the Crlz1 promoter were opened in pre-B cells. H3 (see 602810) and H4 (see 602822) histones were hyperacetylated in the chromatin of Crlz1 in pre-B cells, whereas those in the chromatin of IgJ were hyperacetylated in plasma cells. Lim et al. (2006) concluded that the CRLZ1-IgJ locus shows stage-specific gene expression regulation, and they proposed that additional regulatory elements may exist between the genes to coordinate chromatin accessibility and histone acetylation over the locus. ... More on the omim web site
Oct. 20, 2020: Protein entry updated
Automatic update: Entry updated from uniprot information.
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Nov. 23, 2017: Protein entry updated
Automatic update: Uniprot description updated
March 25, 2017: Additional information
No protein expression data in P. Mayeux work for IGJ
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 147790 was added.
Feb. 25, 2016: Protein entry updated
Automatic update: model status changed
Feb. 24, 2016: Protein entry updated
Automatic update: model status changed
Jan. 24, 2016: Protein entry updated
Automatic update: model status changed