Connexin & Pannexin Antibody Explorer Kit

Gap junctions are usually found in clusters and enable intercellular communication by allowing the passage of small molecules between cells¹. They play important roles in different biological processes. These include differentiation, cell cycle synchronization, cellular development, neuronal activity and the immune response^2-4.

Proteins involved in gap junction formation are composed of four transmembrane domains, 2 extracellular loops and one intracellular loop and intracellular N- and C-termini^5,6. Several consensus cysteine residues are in the extracellular loop and are essential and necessary for intercellular docking of gap junction hemichannels in the opposing cell membrane^5-7.

Pannexins (Pannexin 1, Pannexin 2 and Pannexin 3) belong to the superfamily of gap junction proteins. Pannexin 1 (PANX1) is ubiquitously expressed, Pannexin 2 (PANX2) is specifically expressed in the human brain and widespread in rodents and Pannexin 3 (PANX3) is also detected in the brain⁸.

Connexins are transmembrane proteins, which oligomerize into hexameres adjusting in hemi-channels (connexons). The docking of connexons between two neighboring cells results in the formation of intercellular channels, which are permeable to ions and small molecules⁹. These channels, which are also known as gap junctions, are characterized by distinct electrophysiological properties. Various physiological and pathological conditions regulate the opening and closing of the channels¹⁰. Several genetic disorders have been identified in which specific connexin genes are mutated¹¹.