Nuclear Genes Involved in Mitochondrial Function and Biogenesis

Mitochondria are subcellular organelles of eukaryotic cells responsible for conserving and converting the bulk of energy released during the oxidation of foodstuffs into ATP, the universal currency of biological energy. This organelle is the modern-day remnant of free-living bacteria that invaded and established themselves in a primitive nucleated cell with a less efficient mode of energy metabolism. Many genes of the invading bacteria have been lost but a substantial number were transferred to the nucleus of the host and only a few are still present in mitochondria. This article summarizes current knowledge about the PET genes that were incorporated during evolution into the host's genome and are now essential for maintaining the functional and structural intactness of mitochondria.