Potassium ions flow freely into or out of cells when the channels are open.
The channels open and close in response to biochemical stimuli. In FY 1998, a team of researchers lead by Dr. Roderick MacKinnon of The Rockefeller University got a closer look at these potassium channels. In FY 1999, Dr. MacKinnon's group examined the chemical properties of the molecule. Model of a potassium channel molecule from a bacterium. Dr. MacKinnon's group expects that potassium channels in all organisms will share this same molecular architecture.