Seroatlas · Human Serome Atlas

JCHAIN

Immunoglobulin J chain

Also known as: IGCJ, IGJ, IGJ_HUMAN, JCH

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession
P01591
Gene
JCHAIN
Ensembl
ENSG00000132465
Chromosome
4
Canonical length
159 aa
Protein class
Plasma proteins, Predicted secreted proteins
Secretome location
Secreted to blood

OverviewNCBI Gene

Enables IgA binding activity and protein homodimerization activity. Contributes to several functions, including immunoglobulin receptor binding activity; peptidoglycan binding activity; and phosphatidylcholine binding activity. Involved in several processes, including glomerular filtration; innate immune response; and positive regulation of respiratory burst. Located in extracellular space. Part of monomeric IgA immunoglobulin complex; pentameric IgM immunoglobulin complex; and secretory dimeric IgA immunoglobulin complex. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

159 residues, UniProt reviewed canonical sequence.

>P01591|JCHAIN
     1  MKNHLLFWGV LAVFIKAVHV KAQEDERIVL VDNKCKCARI TSRIIRSSED PNEDIVERNI
    61  RIIVPLNNRE NISDPTSPLR TRFVYHLSDL CKKCDPTEVE LDNQIVTATQ SNICDEDSAT
   121  ETCYTYDRNK CYTAVVPLVY GGETKMVETA LTPDACYPD

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against JCHAIN can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability
Secreted
Secreted
Yes
Transmembrane segments
0
Mean surface accessibility (rSASA)
0.44
Highest tissue expression
7,466 nTPM

Expression across tissuesHPA

Tissue

  • colon: 7,466 nTPM
  • rectum: 6,028 nTPM
  • duodenum: 5,781 nTPM
  • stomach: 5,567 nTPM
  • small intestine: 4,028 nTPM
  • breast: 2,822 nTPM

Single-cell type

  • plasma cells: 61,470 nCPM
  • foveolar cells: 3,793 nCPM
  • gastric chief cells: 2,753 nCPM
  • parietal cells: 2,350 nCPM
  • pdcs: 1,399 nCPM
  • mucous neck cells: 915 nCPM

Immune cell

  • memory B-cell: 4,194 nTPM
  • plasmacytoid DC: 3,595 nTPM
  • naive B-cell: 2,579 nTPM
  • total PBMC: 1,317 nTPM
  • neutrophil: 28 nTPM
  • basophil: 25 nTPM

Brain region

  • spinal cord: 13 nTPM
  • choroid plexus: 6.6 nTPM
  • white matter: 4.7 nTPM
  • cerebral cortex: 4.5 nTPM
  • medulla oblongata: 3.2 nTPM
  • hypothalamus: 2.4 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance)
1.24
gnomAD pLI
0.03
DepMap mean gene effect
0.01
DepMap dependency class
none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 3% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

Cellular components

Protein domainsUniProt · Pfam · InterPro

  • Immunoglobulin J chain
  • Immunoglobulin J chain

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads JCHAIN as an antibody target. Whether an autoantibody or antibody against JCHAIN could matter depends on whether native JCHAIN is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

JCHAIN is annotated as secreted, so native JCHAIN circulates and is directly accessible to antibodies. Secreted and cell-surface proteins are the autoantibody targets most likely to act like drugs, blocking or depleting the native protein.

Annotation status

The present source text does not explicitly label JCHAIN as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/JCHAIN. Study-independent annotations aggregated from UniProt, Human Protein Atlas, PubMed, IEDB, Pfam, InterPro, Gene Ontology, AlphaFold, gnomAD, DepMap, ClinVar, TCGA. Catalog release seroatlas-reviewed-human-uniprot-20260313.

Seroatlas is the reference for exploring autoantibody and antibody serology at the human-protein level: the autoreactome and human serome, multiplex serology (HuProt, HuScan, VirScan, PhIP-Seq).

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