Claudia Schmidt honored with Otto Hahn Medal
Every day, we produce waste that ends up in trash cans and bags to be picked up by garbage disposal companies. Our cells also produce waste when their components become damaged or non-functional. This is why cells have a ’garbage disposal system‘, as well. The system’s malfunction can have severe consequences as useless molecules could accumulate in the cell. “Some diseases such as cancer, Parkinson’s, or Alzheimer’s are, for example, associated with impaired waste removal in the cell,“ Schmidt explains.
In Alexander Stein’s Research Group Membrane Protein Biochemistry, the biochemist investigated how cells dispose of discarded proteins. Within cells, many of those proteins are located in segregated areas called organelles. By attaching a molecular label – known as ubiquitin – to them, they are marked as ’unusable’. Then, the waste proteins get extracted from the organelles and are degraded in the cytosol. However, many of the discarded molecules are firmly anchored in the organelle membranes. Detaching them for removal is therefore challenging for the cell.
Enzymes with surprising functions
”In my PhD thesis, I wanted to find out how cells manage to first label the proteins they no longer need and then detach them from the organelle membranes,“ explains Schmidt. “To do so, I rebuilt the disposal machinery of the enzyme ubiquitin ligase Doa10 in a test tube for the first time.“ The scientist was able to show that the enzyme not only labels proteins with ubiquitin. Surprisingly, Doa10 also loosens the anchoring in the membrane, which facilitates their removal. “This latter function was previously unknown,“ the biochemist reports. “Different organelles have different disposal systems, but it is likely that the enzymes of these other systems have capabilities similar to Doa10. That is why the findings from my doctoral thesis are highly relevant to other areas of cell biology.“
As a postdoctoral researcher, Schmidt is currently exploring the structure of the enzyme Doa10 as well as its function within cells. At the end of the year, she will take her next career step by starting as a postdoctoral researcher at ETH Zurich (Switzerland). There she will continue to investigate the mechanisms of cellular waste removal.
About the awardee
Claudia Schmidt completed her bachelor‘s degree in biology at Ludwig-Maximilians-Universität München. For her master‘s degree, she moved to Göttingen to join the International Max Planck Research School for Molecular Biology. After graduating, she conducted her PhD in the Research Group Membrane Protein Biochemistry of Alexander Stein at the MPI for Biophysical Chemistry. Since completing her PhD at the end of 2019, she has been working there as a postdoctoral researcher.
About the Otto Hahn Medal
The MPS has annually awarded the Otto Hahn Medal to young researchers for exceptional scientific achievements and outstanding PhD theses since 1978. The aim of the award, which is endowed with 7,500 euros, is to support the young scientists in their further university and research careers abroad.