Scientists can now see how proteins organize and interact, thanks to the tech­nology that created this image of skin tissue. The technique reveals the structure of proteins and the relationships among them in unprece­dented detail, providing information that's vital for understanding disease and cell functions. "When you see the proteins, you immediately also see ... how they interact in an undisturbed environment," says Achilleas Frangakis, the biologist who led the research at the European Molecular ­Biology Laboratory in ­Heidelberg, Germany. "At this resolution, the cell is essentially an uncharted terri­tory."

The research group froze cells to -193 ºC by plunging them into liquid nitrogen, sliced them into 50-nanometer­-thick sections, and illuminated the slices with a beam of electrons. Software refined the resulting electron tomography images into virtual slices that were even thinner--as little as half a nanometer thick. Combinations of such slices enable 3-D viewing, too.