Structural component of gap junctions (By similarity). Gap junctions are dodecameric channels that connect the cytoplasm of adjoining cells. They are formed by the docking of two hexameric hemichannels, one from each cell membrane (By similarity). Small molecules and ions diffuse from one cell to a neighboring cell via the central pore (By similarity). A hemichannel or connexon is composed of a hexamer of connexins. A functional gap junction is formed by the apposition of two hemichannels (By similarity). Forms heteromeric channels with GJB2 (By similarity). Colocalizes with GJB2 at gap junction plaques in the cochlea. The disease is caused by variants affecting the gene represented in this entry. Belongs to the connexin family. Beta-type (group I) subfamily.