The appearance of multicellular organisms implicated the development of several mechanisms of communication, which permit the cells to function in coordination. One of the mechanisms found in all tissues of vertebrates is ensured by the proteins of the connexin family. These integral membrane proteins form channels, which allow for the passage ofcytosolic molecules either between adjacent cells or between the cytosol of these cells and the extracellular environment. We have identified connexin 36 (Cx36) as the sole connexin that functionally links ("couples") the beta-cells which produce insulin within pancreatic islets. In vitro and in vivo experiments have shown that Cx36 and/or the intercellular communications to allow play a role in the control of insulin secretion as well as in the resistance of beta-cells against various aggressions, including those induced by the cytokines that are implicated in diabetes. A polymorphism of Cx36 gene is associated to certain forms of human diabetes, opening the possibility that a therapy targeting this protein may be useful in the treatment of diabetic diseases.