50-year-old Mystery Solved: Protein Tags Regulate Key Ion Channel

... A recently discovered process known as sumoylation -- until now thought to be active only in the nucleus -- also occurs near the cell's surface where it regulates proteins, providing a novel target for the development of new drugs. Researchers show that sumoylation regulates the flow of potassium ions, which determine whether "excitable" cells in the brain, heart and skeletal muscles "fire." ...