Mitochondria have gained new interest because of their pivotal role in apoptosis and in aging. Research in these areas builds on the understanding of classical mitochondrial functions. For example, cytochrome c, which is well-known as a component of oxidative phosphorylation, is now also known to trigger apoptosis when released into the cytosol. This new investigation has, however, also uncovered large gaps in researchers' knowledge of mitochondria. In Dr. Alexander van der Bliek's lab, researchers are searching for factors that regulate the structure of mitochondria and their cristae. This knowledge will help researchers understand how mitochondria change during normal development and during disease.