The ‘mitoflash’ probe cpYFP does not respond to superoxide

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Abstract

Arising from E.-Z. Shen et al. Nature 508, 128–132 (2014); doi:10.1038/nature1301210.1038/nature13012

Ageing and lifespan of organisms are determined by complicated interactions between their genetics and the environment, but the cellular mechanisms remain controversial; several studies suggest that cellular energy metabolism and free radical dynamics affect lifespan, implicating mitochondrial function. Recently, Shen et al.1 provided apparent mechanistic insight by reporting that mitochondrial oscillations of ‘free radical production’, called ‘mitoflashes’, in the pharynx of three-day old Caenorhabditis elegans correlated inversely with lifespan. The interpretation of mitoflashes as ‘bursts of superoxide radicals’ assumes that circularly permuted yellow fluorescent protein (cpYFP) is a reliable indicator of mitochondrial superoxide2, but this interpretation has been criticized because experiments and theoretical considerations both show that changes in cpYFP fluorescence are due to alterations in pH, not superoxide3,4,5,6,7. Here we show that purified cpYFP is completely unresponsive to superoxide, and that mitoflashes do not reflect superoxide generation or provide a link between mitochondrial free radical dynamics and lifespan. There is a Reply to this Brief Communication Arising by Cheng, H. et al. Nature 514, http://dx.doi.org/10.1038/nature13859 (2014).

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Figure 1: Spectroscopic and structural analysis of the ‘mitoflash’ probe cpYFP.

References

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Author information

M.S., A.J.M., T.P.D. and M.P.M. conceived the project. M.S., S.W., Y.G.E. and V.V.B. performed spectroscopic experiments. S.W. and T.P.D. performed modelling of protein structures. All authors contributed to experimental design, discussed the results, and wrote the manuscript.

Correspondence to Markus Schwarzländer.

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Schwarzländer, M., Wagner, S., Ermakova, Y. et al. The ‘mitoflash’ probe cpYFP does not respond to superoxide. Nature 514, E12–E14 (2014) doi:10.1038/nature13858

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