Mitochondrial Trafficking and Processing of Telomerase RNA TERC.

Summary Mitochondrial dysfunctions play major roles in many diseases. However, how mitochondrial stresses are relayed to downstream responses remains unclear. Here we show that the RNA component of mammalian telomerase TERC is imported into mitochondria, processed to a shorter form TERC-53 , and then exported back to the cytosol. We found that the import is regulated by PNPASE, and the processing is controlled by mitochondrion-localized RNASET2. Cytosolic TERC-53 levels respond to changes in mitochondrial functions but have no direct effect on these functions. These findings uncover a mitochondrial RNA trafficking pathway and provide a potential mechanism for mitochondria to relay their functional states to other cellular compartments. Graphical Abstract Highlights • The RNA component of mammalian telomerase TERC is imported into mitochondria • TERC RNA is processed to a shorter form, TERC-53 • TERC-53 is exported from the mitochondria and remains in the cytosol • Cytosolic TERC-53 levels respond to changes in mitochondrial functions The functions of most mitochondrial RNAs imported from the cytosol are poorly understood. Cheng et al. provide evidence that the RNA component of mammalian telomerase TERC is imported into mitochondria, processed to a shorter form TERC-53 , and then exported back to the cytosol. The cytosolic TERC-53 level serves as a potential indicator of mitochondrial functions. [ABSTRACT FROM AUTHOR]