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Available structures
PDBOrtholog search: PDBe RCSB
AliasesCLDN2, claudin 2
External IDsMGI: 1276110 HomoloGene: 9621 GeneCards: CLDN2
Gene location (Human)
X chromosome (human)
Chr.X chromosome (human)[1]
X chromosome (human)
Genomic location for CLDN2
Genomic location for CLDN2
BandXq22.3Start106,900,164 bp[1]
End106,930,861 bp[1]
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr X: 106.9 – 106.93 MbChr X: 139.8 – 139.81 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Claudin-2 is a protein that in humans is encoded by the CLDN2 gene.[5][6] It belongs to the group of claudins.

Members of the claudin protein family, such as CLDN2, are expressed in an organ-specific manner and regulate the tissue-specific physiologic properties of tight junctions (Sakaguchi et al., 2002).[supplied by OMIM][6]


Claudin-2 is expressed in cation-leaky epithelia such as that of the kidney proximal tubule.[7] Mice that are deficient in claudin-2 have reduced reabsorption of Na+ in the proximal tubule, consistent with a role in paracellular transport. Similar results have been obtained with cultured cells, as overexpression in claudin-2 lacking cells leads to increase of permeability for small cations.[8] Furthermore, claudin-2 has been shown to form paracellular channels for water.[9]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000165376 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000047230 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:".
  4. ^ "Mouse PubMed Reference:".
  5. ^ Morita K, Furuse M, Fujimoto K, Tsukita S (March 1999). "Claudin multigene family encoding four-transmembrane domain protein components of tight junction strands". Proc Natl Acad Sci U S A. 96 (2): 511–6. doi:10.1073/pnas.96.2.511. PMC 15167. PMID 9892664.
  6. ^ a b "Entrez Gene: CLDN2 claudin 2".
  7. ^ Muto, S.; Hata, M.; Taniguchi, J.; Tsuruoka, S.; Moriwaki, K.; Saitou, M.; Furuse, K.; Sasaki, H.; Fujimura, A.; Imai, M.; Kusano, E.; Tsukita, S.; Furuse, M. (2010). "Claudin-2-deficient mice are defective in the leaky and cation-selective paracellular permeability properties of renal proximal tubules". Proceedings of the National Academy of Sciences. 107 (17): 8011–8016. doi:10.1073/pnas.0912901107. PMC 2867900. PMID 20385797.
  8. ^ Amasheh, S; Meiri, N; Gitter, A. H.; Schöneberg, T; Mankertz, J; Schulzke, J. D.; Fromm, M (2002). "Claudin-2 expression induces cation-selective channels in tight junctions of epithelial cells". Journal of Cell Science. 115 (Pt 24): 4969–76. doi:10.1242/jcs.00165. PMID 12432083.
  9. ^ Rosenthal, R.; Milatz, S.; Krug, S. M.; Oelrich, B.; Schulzke, J. -D.; Amasheh, S.; Gunzel, D.; Fromm, M. (2010). "Claudin-2, a component of the tight junction, forms a paracellular water channel". Journal of Cell Science. 123 (11): 1913–1921. doi:10.1242/jcs.060665. PMID 20460438.

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