Seroatlas · Human Serome Atlas

CLDN2

Claudin-2

Also known as: CLD2_HUMAN

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

Protein identityUniProt · HPA

UniProt accession
P57739
Gene
CLDN2
Ensembl
ENSG00000165376
Chromosome
X
Canonical length
230 aa
Protein class
Disease related genes, Predicted membrane proteins
Subcellular location
Nucleoplasm,Nucleoli,Vesicles,Plasma membrane,Cell Junctions
Quaternary structure
Homopolymer

OverviewNCBI Gene

This gene product belongs to the claudin protein family whose members have been identified as major integral membrane proteins localized exclusively at tight junctions. Claudins are expressed in an organ-specific manner and regulate tissue-specific physiologic properties of tight junctions. This protein is expressed in the intestine. Alternatively spliced transcript variants with different 5' untranslated region have been found for this gene.[provided by RefSeq, Jan 2010]

Canonical amino-acid sequenceUniProt

230 residues, UniProt reviewed canonical sequence.

>P57739|CLDN2
     1  MASLGLQLVG YILGLLGLLG TLVAMLLPSW KTSSYVGASI VTAVGFSKGL WMECATHSTG
    61  ITQCDIYSTL LGLPADIQAA QAMMVTSSAI SSLACIISVV GMRCTVFCQE SRAKDRVAVA
   121  GGVFFILGGL LGFIPVAWNL HGILRDFYSP LVPDSMKFEI GEALYLGIIS SLFSLIAGII
   181  LCFSCSSQRN RSNYYDAYQA QPLATRSSPR PGQPPKVKSE FNSYSLTGYV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CLDN2 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
Cell surface
Secreted
No
Transmembrane segments
4
Mean surface accessibility (rSASA)
0.38
Highest tissue expression
189 nTPM

Expression across tissuesHPA

Tissue

  • choroid plexus: 189 nTPM
  • kidney: 154 nTPM
  • gallbladder: 95 nTPM
  • seminal vesicle: 85 nTPM
  • liver: 42 nTPM
  • epididymis: 32 nTPM

Single-cell type

  • epididymal efferent duct absorptive cells: 352 nCPM
  • epicardial cells: 52 nCPM
  • choroid plexus epithelial cells: 50 nCPM
  • epididymal efferent duct ciliated cells: 49 nCPM
  • proximal tubule cells: 47 nCPM
  • epididymal principal cells: 42 nCPM

Immune cell

  • basophil: 0 nTPM
  • classical monocyte: 0 nTPM
  • eosinophil: 0 nTPM
  • gdT-cell: 0 nTPM
  • intermediate monocyte: 0 nTPM
  • MAIT T-cell: 0 nTPM

Brain region

  • choroid plexus: 243 nTPM
  • hippocampal formation: 18 nTPM
  • cerebellum: 3.8 nTPM
  • thalamus: 3.3 nTPM
  • cerebral cortex: 1.6 nTPM
  • midbrain: 1.2 nTPM

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CLDN2.

Disease | AllUniProt

Conditions CLDN2 is implicated in, by any mechanism.

  • Azoospermia, obstructive, with nephrolithiasis (OAZON) MIM:301060

Disease | GeneticClinVar

1 pathogenic / likely-pathogenic of 39 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

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)
0.75
gnomAD pLI
0.7
gnomAD missense Z
1.61
DepMap mean gene effect
0.04
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

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of CLDN2 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads CLDN2 as an antibody target. Whether an autoantibody or antibody against CLDN2 could matter depends on whether native CLDN2 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

CLDN2 is annotated at the cell surface, where native CLDN2 is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label CLDN2 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

Canonical record: https://seroatlas.com/gene/CLDN2. 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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