Sodium channels as macromolecular complexes: implications for inherited arrhythmia syndromes.

Mutations in cardiac ion channels and their auxiliary subunits can lead to life-threatening cardiac arrhythmias. In recent years it has become apparent that ion channels are part of large, multi-protein complexes, comprising not only the ion channels and their auxiliary subunits, but also components of the cytoskeleton, regulatory kinases and phosphatases, trafficking proteins, extracellular matrix proteins, and possibly even other ion channels. Disruption of any member of a particular ion channel complex has the potential to disrupt the function of the associated channels, resulting in paroxysmal disease. Understanding the molecular composition of individual ion channel signaling complexes in heart may yield important insights into the molecular basis of cardiac arrhythmias and may suggest novel therapeutic approaches to treatment of these life-threatening conditions.