Function and structure of voltage‐dependent potassium channels

Voltage‐dependent potassium (K + ) channels are the largest group of voltage‐dependent ion channels and more cDNAs have been cloned for voltage‐dependent K + channels than for voltage‐dependent Na + , Ca 2+ , and Cl − channels, the other main categories of voltage‐dependent ion channels. The cloning result was anticipated from electrophysiological measurements because K + currents are by far the most diverse of voltage‐dependent ion currents. In this review K + currents will be classified functionally first and structurally second, an arrangement that follows the historical development of the field. Then, we will examine present attempts to assign the major functions of voltage‐sensing, gating and ion conduction to specific domains of K + channel proteins. Finally, we will describe present understanding of drug interactions with the ion conduction pathway or pore of K + channel proteins.