Mitochondria are key components of our cells. Cell respiration and control of many metabolic and signaling processes take place within them. In order for the biochemical reactions to take place flawlessly, complex interactions between specialized protein molecules are required. Yet up to now, it wasn't known how many of the proteins in cells are also actual components of the mitochondria because the technology for such precise allocation was unavailable. A team working with Prof. Dr. Bettina Warscheid, Prof. Dr. Nils Wiedemann, Prof. Dr. Nikolaus Pfanner and Prof. Dr. Claudine Kraft of the Excellence Cluster CIBSS Centre for Integrative Biological Signaling Studies at the University of Freiburg, and Dr. Sven Dennerlein of the University of Göttingen, have used new methods to examine successfully and precisely the composition human mitochondria. Their results are published in Cell Metabolism.