One gap junction consists of a cluster of closely packed pairs of transmembrane channels, the connexons, through which materials of low MW diffuse from one cell to a neighboring cell. A connexon is composed of a hexamer of connexins. Exclusively expressed in the cochlea of the inner ear, where it is found in cells of the tegmentum vasculosum, cuboidal cells, supporting cells and clear cells. Specifically expressed at the late developmental stages in the cochlea. Belongs to the connexin family. Beta-type (group I) subfamily.