Occludin (IPR002958)

Short name: Occludin

Family relationships


Occludin was the first molecular component of the tight junction to be identified. These are specialised membrane domains that form intercellular contacts between epithelial cells and create a regulated barrier to the paracellular movement of water, solutes and immune cells. They also provide a second type of barrier that contributes to cell polarity by restricting the lateral diffusion of lipids and proteins within cell membranes [PMID: 10361874]. Occludin is an ~65 kDa type II integral membrane protein, which has been shown to have four transmembrane (TM) domains, two extracellular loops and cytoplasmic N- and C-termini. The extracellular loops are chemically quite distinctive, particularly the first, which has an unusually high content of tyrosine and glycine residues (~65%) that alternate along the sequence [PMID: 10361874]. Gene knockout experiments have suggested occludin is an accessory, rather than principal, structural component of tight junctions, since occludin-deficient cells are still able to form tight junctions when cultured in vitro [PMID: 10370242].

GO terms

Biological Process

GO:0070830 bicellular tight junction assembly

Molecular Function

No terms assigned in this category.

Cellular Component

GO:0005923 bicellular tight junction
GO:0016021 integral component of membrane

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.