Using a state-of-the-art imaging technology in which molecules are deep frozen, scientists in Roderick MacKinnon’s lab at Rockefeller University have reconstructed in unprecedented detail the three-dimensional architecture of three channels that provide a path for specific types of ions to travel across a cell’s protective membrane. Because such ions are central to biochemical messaging that allows cells to communicate with one another, the findings have implications for understanding how muscles contract, how the heart maintains its rhythm, and many other physiological processes.