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Primary Information | |
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| BoMiProt ID | Bomi331 |
| Protein Name | Immunoglobulin J chain |
| Organism | Bos taurus |
| Uniprot ID | Q3SYR8 |
| Milk Fraction | Whey, MFGM, Exosome |
| Ref Sequence ID | NP_786967.1 |
| Aminoacid Length | 157 |
| Molecular Weight | 17857 |
| FASTA Sequence | Download |
| Gene Name | JCHAIN |
| Gene ID | 280821 |
| Protein Existence Status | Unreviewed: Experimental evidence at protein level |
Secondary Information | |
| Presence in other biological fluids/tissue/cells | expressed by mucosal and glandular plasma cells; bone marrow, spleen and lymph nodes |
| Endogenous/Bioactive peptides - Fragment - Sequence - Effect | IgG, IgA - Immunomodulatory (Passive immunity) Ref |
| Protein Function | joining (J) chain is a small polypeptide; regulates polymer formation of immunoglobulin (Ig)A and IgM; endows antibodies with high valency of antigen-binding sites, which makes them suitable for agglutinating bacteria and viruses; mediates active external transfer of pIgA and pentameric IgM to exocrine secretions; involved in creating the binding site for polymericIg receptor (pIgR) and secretory component (SC) in the Ig polymers; both the J chain and pIgR/SC are key proteins in secretory immunity; may be a marker for relatively `early' B-cell clones derived from mucosa-associated lymphoid tissue |
| Biochemical Properties | only J-chain-containing polymers show high affnity for the polymeric Ig receptor; J-chain-negative hexameric IgM is at least 15±20-fold more effecient than J-chain-positive pentameric IgM in activating complement; Characterization of J chain released from dimeric, trimeric and tetrameric IgA puriied from the same myeloma serum suggested that the molar J-chain ratio increases with the size of the polymer |
| Significance in milk | provide protection against enteric and other diseases in infants; The primary immunoglobulin in cow colostrum and milk is IgG, whereas the primary immunoglobulin in human milk is IgA; provide passive immunity to protect animals |
| PTMs | glycoprotein; N linked glycosylation at 39th aa in both bovine and humans; contains eight cysteine residues: two (cys15 and cys69) are involved in disulfide bridges with the α or µ chains; and six are involved in intrachain disulfide bridges |
| Site(s) of PTM(s) N-glycosylation, O-glycosylation, Phosphorylation | |
| Bibliography | 1. Max, E. E. and Korsmeyer, S. J. (1985) ‘Human J chain gene. Structure and expression in B lymphoid cells’, Journal of Experimental Medicine, 161(4), pp. 832–849. doi: 10.1084/jem.161.4.832. 2. Wiersma, E. J. et al. (1998) ‘Structural and functional analysis of J chain-deficient IgM.’, Journal of immunology (Baltimore, Md. : 1950), 160(12), pp. 5979–89. Available at: http://www.ncbi.nlm.nih.gov/pubmed/9637512 (Accessed: 3 October 2019). |