Kidney stones—solid, pebble-like grit that forms when too much of certain minerals like calcium are in the urine—can strike men, women, and increasingly, children, and the presence and pain of stones afflicts more than 12 percent of the world’s population. Using the 2017 Nobel Prize-winning technique of cryo-electron microscopy (cryo-EM) to capture a high-resolution image of an ion channel protein, called TRPV5, that removes calcium from urine, researchers from the Perelman School of Medicine at the University of Pennsylvania, Rutgers University Medical School, and Temple University, found fresh clues as to how kidney stones form.