Connexon

A special type of protein composed of an assembly of six subunits that are called connexins.

A connexon of one cell is joined to that of an adjacent cell to form an intercellular channel consisting of 12 connexin subunits.

Clusters of intercellular channels are known as a gap junction because of the minute extracellular 'gap' that separates the apposed plasma membranes.

Each intercellular channel provides an axial channel that interconnects the cytoplasm of the apposed cell directly and permits the passage of ion and other small molecules between adjacent cells