Researchers tracked down mutations in the phosphatase Wip1 in cancer cells that enhance the protein's ability to shut down p53 and stymie the DNA damage repair process. The panel shows how cells respond to a dose of radiation that normally stops cells from dividing. The top row shows the cells one hour after the radiation, and the bottom row shows them 17 hours afterward. Cells with truncated Wip1 (left column) progress normally toward the point of cell division (orange nuclei), but most cells lacking truncated Wip1 (right column) fail to progress (red nuclei). The study appears in The Journal of Cell Biology.