Isolation and characterization of yeast mitochondrial-derived vesicles

Eukaryotic cells are defined by the existence of sub-cellular compartments and organelles, which allow the partitioning of various biochemical pathways into separate compartments. Mitochondria are one such example: they are responsible for energy production and essential metabolic pathways in the cell, as well as fundamental processes such as apoptosis and aging. These processes involve substrates and products that flow between the many organelles within the cell, and there is increasing evidence that direct interorganellar contacts are required. Interestingly, in regard to protein targeting and localization, while the import machinery to mitochondria is well characterized, there is no known protein export mechanism from mitochondria to date.

Vesicular transport is a means of interorganellar communication, and in fact cells release vesicles in order to shuttle lipids, proteins, RNA and DNA between each other. Here we show for the first time that functional mitochondria isolated from Saccharomyces cerevisiae can release vesicles, independent of the fission machinery. Mitochondrial secreted vesicles have a relatively uniform size of about 100nm and selectivity of protein cargo. These results open an exciting new direction of investigation regarding the possible function and importance of mitochondrial derived vesicles.