Mitochondrial 'flashes': a radical concept repHined.
Mitochondrial free radicals and redox poise are central to metabolism and cell fate. Their measurement in living cells remains a major challenge and their in vivo dynamics are poorly understood. Reports of 'superoxide flashes' in single mitochondria have therefore been perceived as a major breakthrough: single mitochondria expressing the genetically encoded sensor circularly permuted yellow fluorescent protein (cpYFP) display spontaneous flashes of fluorescence that are responsive to metabolic changes and stressors. We critically review the evidence that underpins the interpretation of mitochondrial cpYFP flashes as bursts of superoxide production and conclude that flashes do not represent superoxide bursts but instead are caused by transient alkalinisation of the mitochondrial matrix. We provide a revised framework that will help to clarify the interpretation of mitochondrial flashes.
INRES - Chemical Signalling, University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany. markus.schwarzlander@uni-bonn.de
Markus
M
Schwarzländer
Michael P
MP
Murphy
Michael R
MR
Duchen
David C
DC
Logan
Mark D
MD
Fricker
Andrew P
AP
Halestrap
Florian L
FL
Müller
Rosario
R
Rizzuto
Tobias P
TP
Dick
Andreas J
AJ
Meyer
Lee J
LJ
Sweetlove
D000818:Animals; D002470:Cell Survival; D005609:Free Radicals / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism*; D013481:Superoxides / Q000378:metabolism
D005609:Free Radicals; D013481:Superoxides