Cell junction

A cell junction (or intercellular bridge ) is a type of structure that exists within the tissue of a some multicellular organism (- for example true for animals, but not plants, which possess plasmodesmata instead). Cell junctions consist of protein complexes and provide contact between neighbouring cells or between a cell and the extracellular matrix. They also build up the paracellular barrier of epithelia and control the paracellular transport. Cell junctions are especially abundant in epithelial tissues.

In vertebrates, there are three major types of cell junctions:

Invertebrates have several other types of specific junctions, for example Septate junctions or the CeAJ (C. elegans apical junction).
 * Adherens junctions and Desmosomes (Anchoring Junctions)
 * Gap junctions (Communicating Junction)
 * Tight junctions (Occluding Junctions)

Cell junction molecules
The molecules responsible for creating cell junctions include various cell adhesion molecules. There are four main types: selectins, cadherins, integrins, and the immunoglobulin superfamily.