Molecular biologists have found one piece of the complex puzzle of autophagy, the process of ‘self-eating’ performed by all eukaryotic cells — cells with a nucleus — to keep themselves healthy. This finding is important because it allows scientists to control this one aspect of cellular autophagy, and may lead to the ability to control other selective “self-eating” processes. This, in turn, could help illuminate autophagy’s role in aging, immunity, neurodegeneration and cancer.