15 Mar 2001

(From Science press release.) A British and German team has made the surprising discovery that the cell's mitochondria can export peptides into their surrounding environments [reported in tomorrow's issue of Science]. Much is known about how mitochondria, which provide cellular fuel in the form of ATP, import proteins, but the role of this unexpected export mechanism is a mystery at the moment. It may allow mitochondria to better communicate with the rest of the cell. Lesley Young and colleagues identified a protein in the inner membrane of yeast mitochondria that transports peptides out to the cytosol. Related proteins do exist in mammalian mitochondria, suggesting that this export system may exist in higher eukaryotes as well.