Rod MacKinnon studies the physical and chemical principles of biological electricity, particularly the passage of ions across cell membranes. MacKinnon and his team are describing how membrane receptor stimulation, transmembrane voltage, and mechanical forces regulate ion channel activity. They employ cryo-electron microscopy to study the atomic structures of ion channels in isolated form and in the native context of the cell membrane. The team has also developed reconstitution methods to analyze – electrically and optically – ion channels interacting with their protein partners in free-standing membranes. Their aim is to understand the molecular circuitry of life’s electrical system.