Structural component of lens fiber gap junctions. 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. Small molecules and ions diffuse from one cell to a neighboring cell via the central pore. A hemichannel or connexon is composed of a hexamer of connexins. A functional gap junction is formed by the apposition of two hemichannels. Forms heteromeric channels with GJA8. Belongs to the connexin family. Alpha-type (group II) subfamily.