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Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I

The mitochondrial electron transport system (ETS) is responsible for setting and maintaining both the energy and redox charges throughout the cell. Reversible phosphorylation of mitochondrial proteins, particularly via the soluble adenylyl cyclase (sAC)/cyclic AMP (cAMP)/Protein kinase A (PKA) axis,...

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Autores principales: Lark, Daniel S., Reese, Lauren R., Ryan, Terence E., Torres, Maria J., Smith, Cody D., Lin, Chien-Te, Neufer, P. Darrell
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646981/
https://www.ncbi.nlm.nih.gov/pubmed/26635618
http://dx.doi.org/10.3389/fphys.2015.00332
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author Lark, Daniel S.
Reese, Lauren R.
Ryan, Terence E.
Torres, Maria J.
Smith, Cody D.
Lin, Chien-Te
Neufer, P. Darrell
author_facet Lark, Daniel S.
Reese, Lauren R.
Ryan, Terence E.
Torres, Maria J.
Smith, Cody D.
Lin, Chien-Te
Neufer, P. Darrell
author_sort Lark, Daniel S.
collection PubMed
description The mitochondrial electron transport system (ETS) is responsible for setting and maintaining both the energy and redox charges throughout the cell. Reversible phosphorylation of mitochondrial proteins, particularly via the soluble adenylyl cyclase (sAC)/cyclic AMP (cAMP)/Protein kinase A (PKA) axis, has recently been revealed as a potential mechanism regulating the ETS. However, the governance of cAMP/PKA signaling and its implications on ETS function are incompletely understood. In contrast to prior reports using exogenous bicarbonate, we provide evidence that endogenous CO(2) produced by increased tricarboxylic acid (TCA) cycle flux is insufficient to increase mitochondrial cAMP levels, and that exogenous addition of membrane permeant 8Br-cAMP does not enhance mitochondrial respiratory capacity. We also report important non-specific effects of commonly used inhibitors of sAC which preclude their use in studies of mitochondrial function. In isolated liver mitochondria, inhibition of PKA reduced complex I-, but not complex II-supported respiratory capacity. In permeabilized myofibers, inhibition of PKA lowered both the K(m) and V(max) for complex I-supported respiration as well as succinate-supported H(2)O(2) emitting potential. In summary, the data provided here improve our understanding of how mitochondrial cAMP production is regulated, illustrate a need for better tools to examine the impact of sAC activity on mitochondrial biology, and suggest that cAMP/PKA signaling contributes to the governance of electron flow through complex I of the ETS.
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spelling pubmed-46469812015-12-03 Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I Lark, Daniel S. Reese, Lauren R. Ryan, Terence E. Torres, Maria J. Smith, Cody D. Lin, Chien-Te Neufer, P. Darrell Front Physiol Physiology The mitochondrial electron transport system (ETS) is responsible for setting and maintaining both the energy and redox charges throughout the cell. Reversible phosphorylation of mitochondrial proteins, particularly via the soluble adenylyl cyclase (sAC)/cyclic AMP (cAMP)/Protein kinase A (PKA) axis, has recently been revealed as a potential mechanism regulating the ETS. However, the governance of cAMP/PKA signaling and its implications on ETS function are incompletely understood. In contrast to prior reports using exogenous bicarbonate, we provide evidence that endogenous CO(2) produced by increased tricarboxylic acid (TCA) cycle flux is insufficient to increase mitochondrial cAMP levels, and that exogenous addition of membrane permeant 8Br-cAMP does not enhance mitochondrial respiratory capacity. We also report important non-specific effects of commonly used inhibitors of sAC which preclude their use in studies of mitochondrial function. In isolated liver mitochondria, inhibition of PKA reduced complex I-, but not complex II-supported respiratory capacity. In permeabilized myofibers, inhibition of PKA lowered both the K(m) and V(max) for complex I-supported respiration as well as succinate-supported H(2)O(2) emitting potential. In summary, the data provided here improve our understanding of how mitochondrial cAMP production is regulated, illustrate a need for better tools to examine the impact of sAC activity on mitochondrial biology, and suggest that cAMP/PKA signaling contributes to the governance of electron flow through complex I of the ETS. Frontiers Media S.A. 2015-11-17 /pmc/articles/PMC4646981/ /pubmed/26635618 http://dx.doi.org/10.3389/fphys.2015.00332 Text en Copyright © 2015 Lark, Reese, Ryan, Torres, Smith, Lin and Neufer. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Physiology
Lark, Daniel S.
Reese, Lauren R.
Ryan, Terence E.
Torres, Maria J.
Smith, Cody D.
Lin, Chien-Te
Neufer, P. Darrell
Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I
title Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I
title_full Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I
title_fullStr Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I
title_full_unstemmed Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I
title_short Protein Kinase A Governs Oxidative Phosphorylation Kinetics and Oxidant Emitting Potential at Complex I
title_sort protein kinase a governs oxidative phosphorylation kinetics and oxidant emitting potential at complex i
topic Physiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4646981/
https://www.ncbi.nlm.nih.gov/pubmed/26635618
http://dx.doi.org/10.3389/fphys.2015.00332
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