On October 29 our colleague Stefan Jentsch passed away at the age of 61 after a short and severe illness. His 35-year career was distinguished by groundbreaking research in cell biology, and extraordinary passion and talent for inspiring and mentoring the next generation of biologists.

Stefan Jentsch made numerous pioneering contributions to our understanding of regulation by ubiquitin and ubiquitin-like proteins.  He was extraordinarily gifted at identifying new, often unprecedented biological regulatory mechanisms.  Although the modification of proteins with the small protein ubiquitin was originally thought to predominantly promote protein degradation by the proteasome, Stefan Jentsch discovered that a vast array of modifications by ubiquitin and related proteins fulfill a plethora of additional essential functions in cellular regulation.  Amongst these, he found that the ubiquitin system plays critical roles in DNA repair and maintaining genome stability.  His fundamental discoveries illuminated new molecular mechanisms of mutagenesis, and are of high medical relevance for understanding the origin of genetic diseases, including cancer.

Stefan Jentsch studied biology at the Free University of Berlin (1974-79), and performed his doctoral thesis on "DNA Modifications by Methyltransferases" with Thomas A. Trautner at the MPI for Molecular Genetics (Ph.D. in 1983).  During his postdoctoral studies with Alexander Varshavsky at the Massachusetts Institute of Technology (1985-88), Stefan began his groundbreaking work on cellular regulation by the ubiquitin system.  This topic henceforth played a central role in all his research, and he opened up many new fields, initially at the Friedrich-Miescher-Laboratory of the Max Planck Society in Tübingen (1988-93) and at the Center for Molecular Biology in Heidelberg (ZMBH).  Stefan Jentsch has been a scientific member of the Max Planck Society and Director of the Molecular Cell Biology Department at the Max Planck Institute for Biochemistry in Martinsried since 1998.

Stefan Jentsch was one of the internationally recognized, truly outstanding scientists in the field of molecular cell biology.  His laboratory was both extraordinarily productive and most uncommonly creative. For his fundamental contributions to our understanding of cellular regulation by ubiquitin and ubiquitin-related proteins he received many awards, including the Gottfried Wilhelm Leibniz Prize of the German Research Council, the Max Planck Research Prize, and the Louis-Jeantet Prize for Medicine.

In addition to his research, Stefan Jentsch is widely recognized as an extraordinary mentor. He was dedicated to training young scientists at all levels. He leaves a remarkably rich legacy of doctoral and postdoctoral students who have gone on to become internationally successful scientists. Stefan Jentsch had an infectious enthusiasm for science. He also instilled a genuine collegiality across the generations of his students.

In Stefan Jentsch we lose not only an outstanding scientist, but also a wonderful colleague. He was torn far too early from our midst. His tragic, untimely death is an irreplaceable loss for the world’s scientific community and for all of us at the institute.