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PDB, Structure of the Colied-coil domain of human Occludin(aa. 416-522)
Available structures
PDB Ortholog search: PDBe, RCSB
External IDs OMIM602876 MGI106183 HomoloGene1905 GeneCards: OCLN Gene
EC number
Species Human Mouse
Entrez 100506658 18260
Ensembl ENSG00000197822 ENSMUSG00000021638
UniProt Q16625 Q61146
RefSeq (mRNA) NM_001205254 NM_008756
RefSeq (protein) NP_001192183 NP_032782
Location (UCSC) Chr 5:
68.79 – 68.85 Mb
Chr 13:
100.5 – 100.55 Mb
PubMed search [1] [2]

Occludin is a protein that in humans is encoded by the OCLN gene.[1][2] Occludin is a 65-kDa (522-amino acid polypeptide -human) integral plasma-membrane protein located at the tight junctions, described for the first time in 1993 by Shoichiro Tsukita.[3] Together with the Claudin group of proteins, it is the main component of the tight junctions.


According to its overall hydrophilicity, occludin appears to span the plasma membrane four times, forming two extracellular loops and exposing its NH2 and COOH terminus to the cytosol. Interaction of occludin with several cytoplasmic proteins of the junctional plaque has been found to occur via its COOH terminus, while the extracellular loops are thought to be involved in the regulation of paracellular permeability and cell adhesion. Phosphorylation/dephosphorylation plays a major role in regulation of occludin and tight junctions.

Disease linkage[edit]

Disruption of occludin regulation is an important aspect of a number of diseases. Strategies to prevent and/or reverse occludin downregulation may be an important therapeutic target.

Diagram of Tight junction.


Occludin has been shown to interact with Tight junction protein 2,[4][5][6] YES1[7] and Tight junction protein 1.[8][9]


  1. ^ Ando-Akatsuka Y, Saitou M, Hirase T, Kishi M, Sakakibara A, Itoh M, Yonemura S, Furuse M, Tsukita S (May 1996). "Interspecies diversity of the occludin sequence: cDNA cloning of human, mouse, dog, and rat-kangaroo homologues". J Cell Biol 133 (1): 43–47. doi:10.1083/jcb.133.1.43. PMC 2120780. PMID 8601611. 
  2. ^ "Entrez Gene: OCLN occludin". 
  3. ^ Furuse M, Hirase T, Itoh M, Nagafuchi A, Yonemura S, Tsukita S, Tsukita S (1993). "Occludin: a novel integral membrane protein localizing at tight junctions". J. Cell Biol. 123 (6 Pt 2): 1777–1788. doi:10.1083/jcb.123.6.1777. PMC 2290891. PMID 8276896. 
  4. ^ Peng, Bi-Hung; Lee J Ching; Campbell Gerald A (Dec 2003). "In vitro protein complex formation with cytoskeleton-anchoring domain of occludin identified by limited proteolysis". J. Biol. Chem. (United States) 278 (49): 49644–49651. doi:10.1074/jbc.M302782200. ISSN 0021-9258. PMID 14512431. 
  5. ^ Itoh, M; Morita K; Tsukita S (Feb 1999). "Characterization of ZO-2 as a MAGUK family member associated with tight as well as adherens junctions with a binding affinity to occludin and alpha catenin". J. Biol. Chem. (UNITED STATES) 274 (9): 5981–5986. doi:10.1074/jbc.274.9.5981. ISSN 0021-9258. PMID 10026224. 
  6. ^ Wittchen, E S; Haskins J; Stevenson B R (Dec 1999). "Protein interactions at the tight junction. Actin has multiple binding partners, and ZO-1 forms independent complexes with ZO-2 and ZO-3". J. Biol. Chem. (UNITED STATES) 274 (49): 35179–35185. doi:10.1074/jbc.274.49.35179. ISSN 0021-9258. PMID 10575001. 
  7. ^ Chen, Yan-Hua; Lu Qun; Goodenough Daniel A; Jeansonne Beverly (Apr 2002). "Nonreceptor tyrosine kinase c-Yes interacts with occludin during tight junction formation in canine kidney epithelial cells". Mol. Biol. Cell (United States) 13 (4): 1227–1237. doi:10.1091/mbc.01-08-0423. ISSN 1059-1524. PMC 102264. PMID 11950934. 
  8. ^ Fanning, A S; Jameson B J; Jesaitis L A; Anderson J M (Nov 1998). "The tight junction protein ZO-1 establishes a link between the transmembrane protein occludin and the actin cytoskeleton". J. Biol. Chem. (UNITED STATES) 273 (45): 29745–29753. doi:10.1074/jbc.273.45.29745. ISSN 0021-9258. PMID 9792688. 
  9. ^ Rao, Radhakrishna K; Basuroy Shyamali, Rao Vijay U, Karnaky Jr Karl J, Gupta Akshay (Dec 2002). "Tyrosine phosphorylation and dissociation of occludin-ZO-1 and E-cadherin-beta-catenin complexes from the cytoskeleton by oxidative stress". Biochem. J. (England) 368 (Pt 2): 471–81. doi:10.1042/BJ20011804. ISSN 0264-6021. PMC 1222996. PMID 12169098. 

Further reading[edit]

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