CLDN2

CLDN2
Identifiers
Aliases	CLDN2, claudin 2, OAZON
External IDs	OMIM: 300520; MGI: 1276110; GeneCards: CLDN2
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 4YYX
Gene location (Human) Chr. X chromosome (human) Band Xq22.3 Start 106,900,164 bp End 106,930,861 bp
Gene location (Mouse) Chr. X chromosome (mouse) Band X|X F1 Start 138,701,577 bp End 138,712,135 bp
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in pancreatic ductal cell gallbladder islet of Langerhans right lobe of liver seminal vesicula renal cortex renal medulla duodenum caput epididymis human kidney Top expressed in Epithelium of choroid plexus human kidney proximal tubule right kidney choroid plexus of fourth ventricle crypt of lieberkuhn of small intestine efferent ductule left colon yolk sac left lobe of liver More reference expression data BioGPS n/a
Gene ontology Molecular function protein binding identical protein binding structural molecule activity Cellular component cell junction integral component of membrane bicellular tight junction plasma membrane membrane Biological process calcium-independent cell-cell adhesion via plasma membrane cell-adhesion molecules Sources:Amigo / QuickGO
Orthologs Databases NCBI: entry; OMA: entry Species Human Mouse Entrez 9075 12738 Ensembl ENSG00000165376 ENSMUSG00000047230 UniProt P57739 O88552 RefSeq (mRNA) NM_020384 NM_001171092 NM_001171095 NM_016675 RefSeq (protein) NP_001164563 NP_001164566 NP_065117 NP_057884 Location (UCSC) Chr X: 106.9 – 106.93 Mb Chr X: 138.7 – 138.71 Mb PubMed search
Wikidata
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Claudin-2 is a protein that in humans is encoded by the CLDN2 gene. 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]

Function

Claudin-2 is expressed in cation-leaky epithelia such as that of the kidney proximal tubule. 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. Furthermore, claudin-2 has been shown to form paracellular channels for water.