Gap Junction Channel Protein

Gap junction channel proteins are integral membrane proteins that form gap junctions—specialized intercellular connections that facilitate direct communication between adjacent cells. These channels allow the passage of ions, metabolites, and small signaling molecules (typically up to 1–1.5 kDa) between the cytoplasms of neighboring cells. This intercellular exchange is crucial for numerous physiological processes including development, differentiation, electrical conduction in excitable tissues (like heart and brain), metabolic cooperation, and immune responses. The primary gap junction channel proteins are called connexins in vertebrates and innexins in invertebrates. Pannexins are a related family. Each gap junction channel is composed of two hemichannels (connexons), one from each adjacent cell. Each hemichannel is a hexamer—a ring of six connexin monomers—resulting in a dodecameric structure for the complete channel spanning both membranes.

Other names

ConnexinsInnexinsPannexinsGap junction proteinsGJA1 (Connexin43)Cx43 (Connexin43)