Collaborative work of research groups at the University of Würzburg and the TU Dresden has provided important new insights for cancer research. During cell division specific target proteins have to be turned over in a precisely regulated manner. To this end specialized enzymes label the target proteins with signaling molecules. However, the enzymes involved in this process can also label themselves, thus initiating their own degradation. In a multidisciplinary approach, the researchers identified a mechanism of how enzymes can protect themselves from such self-destruction and maintain sufficient concentrations in the cell. These results have been published in the journal Science Signaling.