Grant: Project Grant

In this study we will examine a complex protein that is able to conduct potassium and has a vital role in maintaining the normal resting activity of many excitable tissues. This protein is made up of two or three subunits which greatly affect its behavior when they combine with it. The approach proposed in this study is to express the individual genes that code for the human potassium ion channel, IKs, and its partner subunits and then study the complexes together in a cell-based system. The work will entail using two different drug compounds that can activate the subunits by direct action at specific molecular sites. Powerful genetic techniques combined with electrical analysis of the channel function will be used to identify and locate the exact sites in different parts of the ion channel complexes that contribute to the binding of the compounds, and how different components of the channel complex interact together to allow the drug compounds to exert their action. The studies will be complemented with cryo-electron microscopy and computer simulations to gain a greater understanding of how the protein functions on its own and when exposed to the channel-activating compounds. We will be the first group to use these kind of very detailed biophysical methods and specific genetic expression methodology, combined with cryo-electron microscopy and computer simulations to understand how the partners in this IKs channel complex work together when exposed to chemical compounds that can increase the activity of the channel complex during the activation and relaxation phases of the electrical cycle in the heart. We expect to obtain completely new information about the relationships between these proteins when they are activated by specific compounds that will allow us to construct a model of how they act in concert during the normal functioning of the heartbeat, and how the drugs specifically bind to the channels to exert their action.