Pannexin

Pannexins (from Greek 'παν' — all, and from Latin 'nexus' — connection) are a family of vertebrate proteins identified by their homology to the invertebrate innexins. While innexins are responsible for forming gap junctions in invertebrates, the pannexins have been shown to predominantly exist as large transmembrane channels connecting the intracellular and extracellular space, allowing the passage of ions and small molecules between these compartments (such as ATP and sulforhodamine B).