Potential mechanisms linking SIRT activity and hypoxic 2-hydroxyglutarate generation: No role for direct enzyme (de)acetylation

Sergiy M. Nadtochiy, Yves T. Wang, Jimmy Zhang, Keith Nehrke, Xenia Schafer, Kevin Welle, Sina Ghaemmaghami, Josh Munger, Paul S. Brookes

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

2-Hydroxyglutarate (2-HG) is a hypoxic metabolite with potentially important epigenetic signaling roles. The mechanisms underlying 2-HG generation are poorly understood, but evidence suggests a potential regulatory role for the sirtuin family of lysine deacetylases. Thus, we hypothesized that the acetylation status of the major 2-HG-generating enzymes [lactate dehydrogenase (LDH), isocitrate dehydrogenase (IDH) and malate dehydrogenase (MDH)] may govern their 2-HG-generating activity. In vitro acetylation of these enzymes, with confirmation by western blotting, mass spectrometry, reversibility by recombinant sirtuins and an assay for global lysine occupancy, yielded no effect on 2-HG-generating activity. In addition, while elevated 2-HG in hypoxia is associated with the activation of lysine deacetylases, we found that mice lacking mitochondrial SIRT3 exhibited hyperacetylation and elevated 2-HG. These data suggest that there is no direct link between enzyme acetylation and 2-HG production. Furthermore, our observed effects of in vitro acetylation on the canonical activities of IDH, MDH and LDH appeared to contrast with previous findings wherein acetyl-mimetic lysine mutations resulted in the inhibition of these enzymes. Overall, these data suggest that a causal relationship should not be assumed between acetylation of metabolic enzymes and their activities, canonical or otherwise.

Original languageEnglish
Pages (from-to)2829-2839
Number of pages11
JournalBiochemical Journal
Volume474
Issue number16
DOIs
StatePublished - 15 Aug 2017
Externally publishedYes

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