Mitochondria-derived ROS activate AMP-activated protein kinase (AMPK) indirectly.

TitleMitochondria-derived ROS activate AMP-activated protein kinase (AMPK) indirectly.
Publication TypeJournal Article
Year of Publication2018
AuthorsHinchy, EC, Gruszczyk, AV, Willows, R, Navaratnam, N, Hall, AR, Bates, G, Bright, TP, Krieg, T, Carling, D, Murphy, MP
JournalJ Biol Chem
Volume293
Issue44
Pagination17208-17217
Date Published2018 11 02
ISSN1083-351X
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 (HO) 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 HO 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.

DOI10.1074/jbc.RA118.002579
Alternate JournalJ. Biol. Chem.
Citation Key10.1074/jbc.RA118.002579
PubMed ID30232152
PubMed Central IDPMC6222118
Grant List / / Wellcome Trust / United Kingdom
MC_UU_00015/3 / / Medical Research Council / United Kingdom
MC_US_A654_5QB10 / / Medical Research Council / United Kingdom
110159/Z/15/Z / / Wellcome Trust / United Kingdom