IgM
IgM is the pentameric immunoglobulin whose assembly depends on the immunoglobulin J chain, encoded by JCHAIN (also known as IGCJ, JCH or IGJ). The J chain links two monomer units of IgM or IgA and helps these immunoglobulins bind to secretory component. Browse Assay Genie's current range of IgM research reagents below, or read on for the biology behind the target.
The immunoglobulin J chain 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. In the case of IgA, the J chain induces dimers and larger polymers. It also helps these immunoglobulins bind to secretory component. Studies of IgM often therefore consider both the heavy and light chain assembly and the J chain that joins the units together.
The JCHAIN gene encodes the J chain, a secreted protein. According to the NCBI Gene summary, it enables IgA binding and protein homodimerization activity, and contributes to immunoglobulin receptor binding, peptidoglycan binding and phosphatidylcholine binding. It is part of the monomeric IgA immunoglobulin complex, the pentameric IgM immunoglobulin complex and the secretory dimeric IgA immunoglobulin complex. The mouse ortholog is Jchain, which is useful for researchers working with murine models of immunoglobulin biology.
The gene is annotated as involved in glomerular filtration, innate immune response and positive regulation of respiratory burst. Its approved name, joining chain of multimeric IgA and IgM, reflects its role in polymeric immunoglobulin assembly. Earlier names include immunoglobulin J polypeptide and linker protein for immunoglobulin alpha and mu polypeptides, and the symbol IGJ was used previously. Researchers searching for the IgM J chain, an IgM antibody or an IgM ELISA kit will find that the same JCHAIN gene underlies the polymeric forms of both IgM and IgA.
The J chain links monomer units and nucleates the IgM pentamer, making it central to studies of how polymeric immunoglobulins are built.
The J chain induces IgA dimers and larger polymers and helps them bind secretory component, a key feature of secretory IgA.
JCHAIN is annotated as involved in innate immune response and positive regulation of respiratory burst, and binds peptidoglycan.
The J chain contributes to immunoglobulin receptor binding, supporting research into how polymeric immunoglobulins interact with their receptors.
The J chain links two monomer units of IgM. The J chain-joined dimer then acts as a nucleating unit for the IgM pentamer. It also helps IgM bind to secretory component. The same chain links IgA monomers into dimers and larger polymers.
The HGNC symbol is JCHAIN, and the approved name is joining chain of multimeric IgA and IgM. Aliases and previous symbols include IGCJ, JCH and IGJ. Earlier names were immunoglobulin J polypeptide and linker protein for immunoglobulin alpha and mu polypeptides.
A mouse ortholog, Jchain, is recognised. No rat ortholog is given in the data used here. As with any reagent, check the datasheet of any product for its validated reactivity before using it in a given species.
Other immunoglobulin isotypes and polymeric immunoglobulin pathway targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P01591; product specifications from Assay Genie datasheets.