Visualizing cardiac ion channel trafficking pathways

Understanding cardiac electrical and mechanical function requires knowledge of cardiac muscle at the subcellular level. Traditional biochemical and electrophysiological techniques have provided invaluable information in the description of ion channels and their occurrence in various tissues. This knowledge is the basis for our current ability to understand how subcellular ion channel localization occurs and is regulated. We are now in an era whereby individual ion channels can be followed from the moment of their synthesis to placement on the plasma membrane, movements within the membrane, internalization back into the cytoplasm, and degradation. Such insight opens many possibilities for the dissection of regulatory elements governing ion channel expression and function, which will in turn be translated to future therapies for cardiac disease. In this chapter, we discuss the structure of cardiomyocytes and their submembrane domains, the ion channels that we study, and the techniques that can be employed to visualize cardiac ion channel trafficking in real time.