[Mitochondria and the aging process].

Mitochondrion is an organelle that plays major roles in energy metabolism, which is regu- lated by three mitochondrial products of the Sirtuin genes. The energy metabolism accom- panies the sub-production of reactive oxygen species, which may damage mitochondrion itself, its own DNA and various cell components by oxidation, but which function as physiologi- cally important signal molecules. Damaged mitochondria are removed by mitophagy to main- tain the quality of mitochondria. Mitochondrion plays essential roles in innate immunity. Mitochondrion exerts a multiple function to be involved in the aging process.