What is connexine?

Connexins are a family of proteins that form gap junctions, specialized membrane-spanning channels that allow direct cytoplasmic communication between adjacent cells. Connexin proteins have a characteristic structure with four transmembrane domains, two extracellular loops, one intracellular loop, and intracellular N- and C-termini. There are currently 21 known human connexin genes, which encode for 21 different connexin proteins. Each connexin protein can interact with another connexin protein to form a hemichannel or connexon, which binds with hemichannels of adjacent cells to form a functional gap junction channel. Connexins have been implicated in a wide range of physiological processes, including cell growth regulation, cell differentiation, and tissue development. Dysfunction or mutations in connexins have also been linked to various diseases, including deafness, cataracts, skin disorders, and genetic syndromes.