Occludin (IPR002958)

Short name: Occludin

Overlapping homologous superfamilies


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.