Nuclear depletion of apurinic/apyrimidinic endonuclease 1 (Ape1/Ref-1) is an indicator of energy disruption in neurons

Shilpee Singh, Ella W. Englander

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Apurinic/apyrimidinic endonuclease 1 (Ape1/Ref-1) is a multifunctional protein critical for cellular survival. Its involvement in adaptive survival responses includes key roles in redox sensing, transcriptional regulation, and repair of DNA damage via the base excision repair (BER) pathway. Ape1 is abundant in most cell types and central in integrating the first BER step catalyzed by different DNA glycosylases. BER is the main process for removal of oxidative DNA lesions in postmitotic brain cells, and after ischemic brain injury preservation of Ape1 coincides with neuronal survival, while its loss has been associated with neuronal death. Here, we report that in cultured primary neurons, diminution of cellular ATP by either oligomycin or H2O 2 is accompanied by depletion of nuclear Ape1, while other BER proteins are unaffected and retain their nuclear localization under these conditions. Importantly, while H2O2 induces γH2AX phosphorylation, indicative of chromatin rearrangements in response to DNA damage, oligomycin does not. Furthermore, despite comparable diminution of ATP content, H2O2 and oligomycin differentially affect critical parameters of mitochondrial respiration that ultimately determine cellular ATP content. Taken together, our findings demonstrate that in neurons, nuclear compartmentalization of Ape1 depends on ATP and loss of nuclear Ape1 reflects disruption of neuronal energy homeostasis. Energy crisis is a hallmark of stroke and other ischemic/hypoxic brain injuries. In vivo studies have shown that Ape1 deficit precedes neuronal loss in injured brain regions. Thus, our findings bring to light the possibility that energy failure-induced Ape1 depletion triggers neuronal death in ischemic brain injuries.

Original languageEnglish (US)
Pages (from-to)1782-1790
Number of pages9
JournalFree Radical Biology and Medicine
Issue number9
StatePublished - Oct 1 2012
Externally publishedYes


  • ATP
  • Ape1
  • Base excision repair
  • DNA damage
  • Ischemia
  • Mitochondrial respiration
  • Neuron

ASJC Scopus subject areas

  • Biochemistry
  • Physiology (medical)


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