Gap junctions consist of Connexins (Cx), a family of proteins that form channels linking the cytoplasm of adjacent cells. All Connexin molecules have four membrane-spanning domains, two extracellular domains, and a cytoplasmic carboxy-terminal tail of varying length that has an important role in the regulation of the gating properties of the channel. Interestingly Connexin 43 also known as gap junction alpha-1 protein is one of the most abundant gap-junction protein.
