Gap junction beta-6 protein (GJB6), also known as connexin 30 (Cx30) — is a protein that in humans is encoded by the GJB6 gene. Connexin 30 (Cx30) is one of several gap junction proteins expressed in the inner ear. Mutations in gap junction genes have been found to lead to both syndromic and nonsyndromic deafness.
The connexin gene family codes for the protein subunits of gap junction channels that mediate direct diffusion of ions and metabolites between the cytoplasm of adjacent cells. Connexins span the plasma membrane 4 times, with amino- and carboxy-terminal regions facing the cytoplasm. Connexin genes are expressed in a cell type-specific manner with overlapping specificity. The gap junction channels have unique properties depending on the type of connexins constituting the channel.[supplied by OMIM]
Connexin 30 is prevalent in the two distinct gap junction systems found in the cochlea: the epithelial cell gap junction network, which couple non-sensory epithelial cells, and the connective tissue gap junction network, which couple connective tissue cells. Gap junctions serve the important purpose of recycling potassium ions that pass through hair cells during mechanotransduction back to the endolymph.