Mitochondria-derived ROS activate AMP-activated protein kinase (AMPK) indirectly.
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Authors
Hinchy, Elizabeth C
Gruszczyk, Anja V
Willows, Robin
Navaratnam, Naveenan
Hall, Andrew R
Bates, Georgina
Bright, Thomas P
Krieg, Thomas
Publication Date
2018-11-02Journal Title
J Biol Chem
ISSN
0021-9258
Publisher
Elsevier BV
Volume
293
Issue
44
Pages
17208-17217
Language
eng
Type
Article
Physical Medium
Print-Electronic
Metadata
Show full item recordCitation
Hinchy, E. C., Gruszczyk, A. V., Willows, R., Navaratnam, N., Hall, A. R., Bates, G., Bright, T. P., et al. (2018). Mitochondria-derived ROS activate AMP-activated protein kinase (AMPK) indirectly.. J Biol Chem, 293 (44), 17208-17217. https://doi.org/10.1074/jbc.RA118.002579
Abstract
Mitochondrial reactive oxygen species (ROS) production is a tightly regulated redox signal that transmits information from the organelle to the cell. Other mitochondrial signals, such as ATP, are sensed by enzymes, including the key metabolic sensor and regulator, AMP-activated protein kinase (AMPK). AMPK responds to the cellular ATP/AMP and ATP/ADP ratios by matching mitochondrial ATP production to demand. Previous reports proposed that AMPK activity also responds to ROS, by ROS acting on redox-sensitive cysteine residues (Cys-299/Cys-304) on the AMPK α subunit. This suggests an appealing model in which mitochondria fine-tune AMPK activity by both adenine nucleotide-dependent mechanisms and by redox signals. Here we assessed whether physiological levels of ROS directly alter AMPK activity. To this end we added exogenous hydrogen peroxide (H2O2) to cells and utilized the mitochondria-targeted redox cycler MitoParaquat to generate ROS within mitochondria without disrupting oxidative phosphorylation. Mitochondrial and cytosolic thiol oxidation was assessed by measuring peroxiredoxin dimerization and by redox-sensitive fluorescent proteins. Replacing the putative redox-active cysteine residues on AMPK α1 with alanines did not alter the response of AMPK to H2O2 In parallel with measurements of AMPK activity, we measured the cell ATP/ADP ratio. This allowed us to separate the effects on AMPK activity due to ROS production from those caused by changes in this ratio. We conclude that AMPK activity in response to redox changes is not due to direct action on AMPK itself, but is a secondary consequence of redox effects on other processes, such as mitochondrial ATP production.
Keywords
Cell Line, Mitochondria, Animals, Humans, Mice, Hydrogen Peroxide, Reactive Oxygen Species, Adenosine Diphosphate, Adenosine Triphosphate, Enzyme Activation, Oxidation-Reduction, Muscle Fibers, Skeletal, AMP-Activated Protein Kinases
Sponsorship
Wellcome Trust (110159/Z/15/Z)
Medical Research Council (MC_UU_00015/3)
Identifiers
External DOI: https://doi.org/10.1074/jbc.RA118.002579
This record's URL: https://www.repository.cam.ac.uk/handle/1810/285683
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