Voltage Clamp Fluorometry: Illuminating the Dynamics of Ion Channels

Ion channels comprise one of the largest targets for drug development and treatment and have been a subject of enduring fascination since first discovered in the 1950s. Over the past decades, thousands of publications have explored the cellular biology and molecular physiology of these proteins, and many channel structures have been determined since the late 1990s. Trying to connect the dots between ion channel function and structure, voltage clamp fluorometry (VCF) emerges as a powerful tool because it allows monitoring of the conformational rearrangements underlying the different functional states of the channel. This technique represents an elegant harmonization of molecular biology, electrophysiology, and fluorescence. In the following chapter, we will provide a concise guide to performing VCF on Xenopus laevis oocytes using the two-electrode voltage clamp (TEVC) modality. This is the most widely used configuration on Xenopus oocytes for its relative simplicity and demonstrated success in a number of different ion channels utilizing a variety of attached labels.