Human polynucleotide phosphorylase, hPNPase, is localized in mitochondria.
Piwowarski J., Grzechnik P., Dziembowski A., Dmochowska A., Minczuk M., Stepien P.P.
The human gene encoding a polynucleotide phosphorylase (hPNPase) has been recently identified as strongly up-regulated in two processes leading to irreversible arrest of cell division: progeroid senescence and terminal differentiation. Here, we demonstrate that the hPNPase is localized in mitochondria. Our finding suggests the involvement of mitochondrial RNA metabolism in cellular senescence.