The role of gap junctions in health and disease

Connexins are transmembrane proteins that allow for effective cell-to-cell communication through the formation of gap junction channels. Both cytokines and hormones, which may be upregulated in various disease states, have been shown to affect connexin expression and gap junction function. A major regulatory mechanism involves the phosphorylation of individual connexin isomers, resulting in changes in channel gating. Mutations in various connexin isoforms may lead to a variety of human diseases, indicating the importance of gap junctions for normal function of many tissues. Further questions in the field relate to the regulation of gap junction function, the precise molecules that are transferred between adjacent cells, and the mechanisms by which gap junction inhibition affects different organ systems under basal and pathologic conditions.