The roles of nectins in cell adhesions: cooperation with other cell adhesion molecules and growth factor receptors. 2007
Tight junctions -Current Opinion in Cell Biology
Role of Nectin in Cell Junction Formation
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Key: t.j. tight junction (occludens), a.b. adhesion belt (adherens), d.s. desmosome (spot), g.j. gap junction (communicating), h.d. hemidesmosome
- tight junction (occludens)
- adhesion belt (adherens)
- desmosome (spot)
- gap junction (communicating)
Schematic representation showing intercellular junctions between epithelial cells of the gut mucosa
The tight junction (also referred to as a zonula occludens) is a site where the membranes of two cells come very close together. In fact, the outer leaflets of the membranes of the contacting cells appear to be fused. Tight junctions, as their name implies, act as a barrier so that materials cannot pass between two interacting cells. The protein components of the tight junction are arranged like beads on a string that span the adjacent membranes of each tight junction.
Tight junctions often occur in a belt completely encircling the cell. In a sheet of such cells, material cannot pass from one side of the sheet to the other by squeezing between cells. Instead, it must go through a cell, and hence the cell can regulate its passage. Such an arrangement is found in the gut, to regulate absorption of digested nutrients.
from: Proteomic and bioinformatic analysis of epithelial tight junction reveals an unexpected cluster of synaptic molecules 2006