Journal
JOURNAL OF IMMUNOLOGY
Volume 170, Issue 12, Pages 6016-6023Publisher
AMER ASSOC IMMUNOLOGISTS
DOI: 10.4049/jimmunol.170.12.6016
Keywords
-
Categories
Funding
- NCRR NIH HHS [RR06603] Funding Source: Medline
- NIAID NIH HHS [R01-AI-08054] Funding Source: Medline
Ask authors/readers for more resources
J chain is a small polypeptide covalently attached to polymeric IgA and IgM. In humans and mice, it plays a role in binding Ig to the polymeric Ig receptor for transport into secretions. The putative orthologue of mammalian J chain has been identified in the nurse shark by sequence analysis of cDNA and the polypeptide isolated from IgM. Conservation with J chains from other species is relatively poor, especially in the carboxyl-terminal portion, and, unlike other J chains, the shark protein is not acidic. The only highly conserved segment in all known J chains is a block of residues surrounding an N-linked glycosylation site. Of the eight half-cystine residues that are conserved in mammalian J chains, three are lacking in the nurse shark, including two in the carboxyl-terminal segment that have been reported to be required for binding of human J chain-containing IgA to secretory component. Taken together with these data, the relative abundance of J chain transcripts in the spleen and their absence in the spiral valve (intestine) suggest that J chain in nurse sharks may not have a role in Ig secretion. Analysis of J chain sequences in diverse species is in agreement with accepted phylogenetic relationships, with the exception of the earthworm, suggesting that the reported presence of J chain in invertebrates should be reassessed.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available