J chain

From Wikipedia, the free encyclopedia

This article does not cite any references or sources. (October 2007)
Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

This article or section may contain original research or unverified claims.
Please improve the article by adding references. See the talk page for details. (October 2007)

IgM (Immunoglobulin M) antibody molecule consisting of 5 base units.
1: Base unit.
2: Heavy chains.
3: Light chains.
4: J chain.
5: Intermolecular disulfide bonds.

The dimeric IgA molecule.
1: H-chain
2: L-chain
3: J-chain
4: secretory component

J chain is a protein component of the antibodies IgM and IgA.

Because IgM and IgA are the only two types of antibody that polymerize, initial hypotheses stated that J chain was required for polymerization. However, it was subsequently found that IgM is able to polymerize in the absence of J chain as both a pentamer and a hexamer.

Current hypotheses indicate that J chain may be necessary to enable secretion of antibodies into mucosal tissues.