Tyrosine phosphorylation in mitochondria: a new frontier in mitochondrial signaling

Mitochondria are multifunctional organelles that participate in a range of cellular processes such as energy production, proliferation, death, and senescence. The involvement of mitochondria in such distinct aspects of cell life requires the existence of an integrated system of signals that enter and exit the organelle according to the diverse needs of the cell. The recent discovery of several protein kinases and phosphatases that localize partially or predominantly inside mitochondria opens new perspectives into the regulation of these signals. This review focuses on tyrosine phosphorylation in mitochondria. A description of the protein tyrosine kinases and phosphatases which regulate this process along with the mitochondrial tyrosine-phosphorylated proteins identified to date is followed by a discussion of the possible involvement of tyrosine phosphorylation in mitochondrial signaling and future perspectives for developments in this emerging field.