Fig. 2.

Intracellular redistribution of TERT upon oxidative stress. Under physiological conditions, TERT is distributed between the nucleus and the mitochondria with the majority being imported into the nucleus. In the nucleus, TERT is required for telomere maintenance and could, in addition, have non-telomeric functions. Mitochondrial TERT binds to and protects mitochondrial DNA (mtDNA), which might help to maintain proper electron transport chain (ETC) function; concomitantly, levels of mitochondrial reactive oxygen species (ROS) decrease. Upon short-term oxidative stress, TERT is exported from the nucleus with a concomitant increase in the mitochondria, which might serve as a mechanism to protect these organelles. Currently it is unclear, whether this is due to direct nuclear-mitochondrial shuttling or increased import of newly synthesized TERT molecules into the mitochondria.