Mitochondria fulfill essential functions like energy conversion for every eukaryotic cell. They have to import about 1000 proteins that are produced as precursors on cytosolic ribosomes. The two mitochondrial membranes are equipped with protein translocases that sort the precursors into both membranes, the intermembrane space and matrix. Our group is interested in the mechanisms and control of protein transport into mitochondria. We investigate quality control mechanisms that remove non-imported proteins and analyze the close to link between protein transport and metabolism in human cell lines and baker’s yeast Saccharomyces cerevisiae. Our goal is to understand how mitochondria are integrated into cellular environment.