Molecular Organization and Regulation of the Cardiac Gap Junction Channel Connexin43

Gap junction channels provide a pathway for direct cell-to-cell communication between adjacent cells. These channels are involved in a number of biologic functions such as electrical conduction, embryogenesis, and cell growth. Mutations of their constituent proteins in humans have been associated with nonsyndromic deafness, Charcot-Marie-Tooth syndrome, oculodentodigital dysplasia, 1 and congenital cataracts among other congenital human diseases. 2 3 In the heart, gap junctions are necessary for the propagation of the action potential 4 5 as well as for normal cardiac embryogenesis. 6 In this chapter, we review the structure of the cardiac gap junctions and correlate it to our current knowledge, with the function of the channel. It is one of the expectations of structure-function analysis that this information may one day translate into, among other things, the rational design of molecules that may either enhance or interfere with the function of the channel, thus providing a new tool for the manipulation of electrical and metabolic synchrony in the heart.