Telomerase does not counteract telomere shortening but protects mitochondrial function under oxidative stress

Shaheda Ahmed, João F. Passos, Matthew J. Birket, Tina Beckmann, Sebastian Brings, Heiko Peters, Mark A. Birch-Machin, Thomas von Zglinicki, Gabriele Saretzki

Research output: Contribution to journalArticle

274 Scopus citations

Abstract

Telomerase is a ribonucleoprotein that counteracts telomere shortening and can immortalise human cells. There is also evidence for a telomere-independent survival function of telomerase. However, its mechanism is not understood. We show here that TERT, the catalytic subunit of human telomerase, protects human fibroblasts against oxidative stress. While TERT maintains telomere length under standard conditions, telomeres under increased stress shorten as fast as in cells without active telomerase. This is because TERT is reversibly excluded from the nucleus under stress in a dose- and tim-dependent manner. Extranuclear telomerase colocalises with mitochondria. In TERT-overexpressing cells, mtDNA is protected, mitochondrial membrane potential is increased and mitochondrial superoxide production and cell peroxide levels are decreased, all indicating improved mitochondrial function and diminished retrograde response. We propose protection of mitochondria under mild stress as a novel function of TERT.

Original languageEnglish (US)
Pages (from-to)1046-1053
Number of pages8
JournalJournal of cell science
Volume121
Issue number7
DOIs
StatePublished - Apr 1 2008

Keywords

  • Mitochondria
  • Oxidative stress
  • Reactive oxygen
  • TERT
  • Telomerase

ASJC Scopus subject areas

  • Cell Biology

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