Microbiology. Unlocking the secrets of the grim reaper.

On page 1594, researchers unveil the workings of YopJ, one of a group of nefarious proteins that Yersinia bacteria--including Y. pestis, the bacterium that is infamous for causing the bubonic plague--deploy. Early in the disease, Yersinia bacteria inject YopJ into macrophage cells of the immune system, where, the researchers have now found, YopJ acts like scissors, cleaving the macrophage proteins that would normally send an SOS to other immune cells for help. Leaving the macrophage stranded clears the way for other Yersinia proteins to destroy the cell.