The Signal Transduction Function for Oxidative Phosphorylation Is at Least Second Order in ADP

To maintain ATP constant in the cell, mitochondria must sense cellular ATP utilization and transduce this demand to F0-F1-ATPase. In spite of a considerable research effort over the past three decades, no combination of signal(s) and kinetic function has emerged with the power to explain ATP homeost...

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Bibliographic Details
Published in:The Journal of biological chemistry 1996-11, Vol.271 (45), p.27995-27998
Main Authors: Jeneson, JeroenA.L., Wiseman, Robert W., Westerhoff, Hans V., Kushmerick, Martin J.
Format: Article
Language:English
Subjects:
Adenosine Diphosphate - metabolism
Animals
Cytosol - metabolism
Dogs
Energy Metabolism
Homeostasis
Humans
Kinetics
Magnetic Resonance Spectroscopy
Mice
Mitochondria, Muscle - metabolism
Muscle, Skeletal - metabolism
Oxidative Phosphorylation
Oxygen Consumption
Proton-Translocating ATPases - metabolism
Signal Transduction
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Summary:To maintain ATP constant in the cell, mitochondria must sense cellular ATP utilization and transduce this demand to F0-F1-ATPase. In spite of a considerable research effort over the past three decades, no combination of signal(s) and kinetic function has emerged with the power to explain ATP homeostasis in all mammalian cells. We studied this signal transduction problem in intact human muscle using 31P NMR spectroscopy. We find that the apparent kinetic order of the transduction function of the signal cytosolic ADP concentration ([ADP]) is at least second order and not first order as has been assumed. We show that amplified mitochondrial sensitivity to cytosolic [ADP] harmonizes with in vitro kinetics of [ADP] stimulation of respiration and explains ATP homeostasis also in mouse liver and canine heart. This result may well be generalizable to all mammalian cells.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.271.45.27995