Travels with ubiquitin: from protein degradation to DNA repair

Uncertain whether to follow full steam my interests in geology or perhaps biology, I entered university in Berlin with the strong desire to become a researcher. Although my geologist's hammer has still its firm place in the trunk of my car, I never regretted my decision to focus on biology. In particular the precision and elegance of genetics attracted me, and this fascination still drives my research. Finishing my PhD studies on the genetics of DNA methylation in bacteria with Thomas Trautner at the Max Planck Institute for Molecular Genetics in Berlin, I watched out for emerging fields in eukaryotic biology and for people who ask the most interesting questions. » I watched out for emerging fields in eukaryotic biology and for people who ask the most interesting questions. « Browsing through Cell , I was struck by two back‐to‐back papers from Alex Varshavsky, a brilliant researcher who was at that time at the MIT, USA. In these two, now classical papers Alex and colleagues reported that protein modification by ubiquitin (‘ubiquitylation’) is not only important for the elimination of abnormal proteins, but also for viability and cell cycle progression. This suggested to me that ubiquitin has much more in store than being merely a ‘garbage controller’. At this time, Alex was already famous for his original research in several other areas, and also the imaginative methods he invented, for example a technique that is now called chromatin immunoprecipitation (ChIP).A few months later, in 1985, equipped with a stipend from the Deutsche Forschungsgemeinschaft (DFG) and a small folder, which contained all published work of this new and exciting field, I started my postdoctoral work in Alex's lab. After periods of frustration and failed experiments, I finally decided to clone the genes that encode ubiquitin‐activating and ‐conjugating enzymes. Hundred litres …