Cells contain complex systems for shipping microscopic cargo, but mutated genes may cause traffic jams. James Rothman of Yale University, Randy Schekman of the University of California, Berkeley, and Thomas Südhof of Stanford University received the Nobel Prize in Medicine yesterday for this discovery, explaining how cells move molecules in a cargo system that docks at the right place at the right time. The scientists found vesicles carrying molecules around everything from yeast cells to human cells. But when disease slows the flow of traffic, the cell is thrown into chaos. It seems that organelles get road rage too.