J chain

JCHAIN
Identifiers
Aliases	JCHAIN, IGCJ, JCH, IGJ, J chain, joining chain of multimeric IgA and IgM
External IDs	MGI: 96493 HomoloGene: 16958 GeneCards: JCHAIN
Gene location (Human) Chr. Chromosome 4 (human) Band 4q13.3 Start 70,655,541 bp End 70,681,817 bp
Gene location (Mouse) Chr. Chromosome 5 (mouse) Band 5|5 E1 Start 88,519,809 bp End 88,527,891 bp
RNA expression pattern More reference expression data
Gene ontology Molecular function • antigen binding • protein homodimerization activity • phosphatidylcholine binding • immunoglobulin receptor binding • single-stranded DNA binding • peptidoglycan binding • IgA binding • protein binding, bridging Cellular component • secretory IgA immunoglobulin complex • blood microparticle • hexameric IgM immunoglobulin complex • monomeric IgA immunoglobulin complex • dimeric IgA immunoglobulin complex • pentameric IgM immunoglobulin complex • secretory dimeric IgA immunoglobulin complex • extracellular exosome • extracellular region • extracellular space Biological process • adaptive immune response • retina homeostasis • glomerular filtration • immune response • innate immune response • positive regulation of respiratory burst • receptor-mediated endocytosis • positive regulation of protein oligomerization • leukocyte migration Sources:Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	3512	16069
Ensembl	ENSG00000132465	ENSMUSG00000067149
UniProt	P01591	P01592
RefSeq (mRNA)	NM_144646	NM_152839
RefSeq (protein)	NP_653247	NP_690052
Location (UCSC)	Chr 4: 70.66 – 70.68 Mb	Chr 4: 88.52 – 88.53 Mb
PubMed search

3512

16069

ENSG00000132465

ENSMUSG00000067149

P01591

P01592

NM_144646

NM_152839

NP_653247

NP_690052

A J chain is a protein component of the antibodies IgM and IgA. It is a 137 residue polypeptide, encoded by the IGJ gene.

The J Chain's molecular weight is approximately 15 kDa. It exhibits a standard immunoglobulin folding structure of two β-pleated sheets of four ribbons folded against one another. It has 8 cystine residues. Two of these residues link the α chains of IgA or the μ chains of IgM via disulfide bridges, effectively serving as the "glue" between two Fc regions of the antibody.

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Wikipedia