Difference between revisions of "Hand 2013 Abstract MiP2013"
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{{Abstract | {{Abstract | ||
|title=Hand SC, Patil Y (2013) Defense against ATP depletion during the energy-limited state of diapause. Mitochondr Physiol Network 18.08. | |title=Hand SC, Patil Y (2013) Defense against ATP depletion during the energy-limited state of diapause. Mitochondr Physiol Network 18.08. | ||
|info=[http://www.mitophysiology.org/?MiP2013 MiP2013], [[Laner 2013 Mitochondr Physiol Network MiP2013|Book of Abstracts Open Access]] | |info=[[File:Hand photo.jpg|right|150px|Steven Hand]] [http://www.mitophysiology.org/?MiP2013 MiP2013], [[Laner 2013 Mitochondr Physiol Network MiP2013|Book of Abstracts Open Access]] | ||
|authors=Hand SC, Patil Y | |authors=Hand SC, Patil Y | ||
|year=2013 | |year=2013 | ||
|event=MiP2013 Programme | |event=MiP2013 Programme | ||
|abstract= | |abstract=Gastrula-stage embryos of ''Artemia franciscana'' (brine shrimp) undergo dramatic respiratory depression and developmental arrest upon release from the adult female as they enter a state of hypometabolism termed diapause [1]. Metabolism as measured by respiration rate declines by over 99% during entry into diapause across a 26-day time course [2]. The primary basis for the inhibition is a restriction of oxidative substrate to the mitochondrion that involves an orchestrated interplay at multiple enzymatic sites including trehalase, hexokinase, pyruvate kinase and pyruvate dehydrogenase [2]. | ||
Gastrula-stage embryos of ''Artemia franciscana'' (brine shrimp) undergo dramatic respiratory depression and developmental arrest upon release from the adult female as they enter a state of hypometabolism termed diapause [1]. Metabolism as measured by respiration rate declines by over 99% during entry into diapause across a 26-day time course [2]. The primary basis for the inhibition is a restriction of oxidative substrate to the mitochondrion that involves an orchestrated interplay at multiple enzymatic sites including trehalase, hexokinase, pyruvate kinase and pyruvate dehydrogenase [2]. | |||
While a substantial decrease in embryo ATP occurs during diapause, a significant amount of ATP remains [e.g., ATP:ADP ratio = 1.306 ± 0.036 (mean ± SE, N = 10)]. This observation is noteworthy when one considers that proton conductances of mitochondria isolated from diapause and post-diapause embryos are identical when compared as a function of the driving force (ΔΨ) [2]. Thus proton leak apparently is not downregulated during diapause, and as a consequence, mitochondrial ΔΨ is likely severely compromised because respiration of intact embryos is depressed far below that required to compensate for leak. Under such conditions, one would predict that the F1Fo-ATP synthase could reverse and fully deplete cellular ATP. Because ATP is not depleted, we predict that the F1Fo-ATP synthase is blocked during diapause by the F1-ATPase inhibitor protein IF1. This 9.6 kDa protein binds to the ATP synthase at the F1 catalytic domain and inhibits the hydrolytic activity of the enzyme under conditions where ΔΨ is low [3]. Further, acidic pH is known to promote the formation of the active dimeric state of IF1 and a stable complex with the enzyme [3]. It is likely that intracellular pH of A. franciscana embryos may decline during diapause as the metabolic depression phase progresses. | While a substantial decrease in embryo ATP occurs during diapause, a significant amount of ATP remains [e.g., ATP:ADP ratio = 1.306 ± 0.036 (mean ± SE, N = 10)]. This observation is noteworthy when one considers that proton conductances of mitochondria isolated from diapause and post-diapause embryos are identical when compared as a function of the driving force (ΔΨ) [2]. Thus proton leak apparently is not downregulated during diapause, and as a consequence, mitochondrial ΔΨ is likely severely compromised because respiration of intact embryos is depressed far below that required to compensate for leak. Under such conditions, one would predict that the F1Fo-ATP synthase could reverse and fully deplete cellular ATP. Because ATP is not depleted, we predict that the F1Fo-ATP synthase is blocked during diapause by the F1-ATPase inhibitor protein IF1. This 9.6 kDa protein binds to the ATP synthase at the F1 catalytic domain and inhibits the hydrolytic activity of the enzyme under conditions where ΔΨ is low [3]. Further, acidic pH is known to promote the formation of the active dimeric state of IF1 and a stable complex with the enzyme [3]. It is likely that intracellular pH of A. franciscana embryos may decline during diapause as the metabolic depression phase progresses. | ||
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|additional=MiP2013, S03 | |additional=MiP2013, S03 | ||
}} | }} | ||
== Affiliations and author contributions == | == Affiliations and author contributions == | ||
1 - Division of Cellular, Developmental, and Integrative Biology, Dept of Biol Sci, Louisiana State University, Baton Rouge, USA; | 1 - Division of Cellular, Developmental, and Integrative Biology, Dept of Biol Sci, Louisiana State University, Baton Rouge, USA; | ||
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# Bason JV, Runswick MJ, Fearnley IM, Walker JE (2011) Binding of the inhibitor protein IF1 to bovine F1-ATPase. J Mol Biol 406: 443-453. | # Bason JV, Runswick MJ, Fearnley IM, Walker JE (2011) Binding of the inhibitor protein IF1 to bovine F1-ATPase. J Mol Biol 406: 443-453. | ||
# Runswick MJ, Bason JV, Montgomery MG, Robinson GC, Fearnley IM, Walker JE (2013) The affinity purification and characterization of ATP synthase complexes from mitochondria. Open Biol 3: 120160. | # Runswick MJ, Bason JV, Montgomery MG, Robinson GC, Fearnley IM, Walker JE (2013) The affinity purification and characterization of ATP synthase complexes from mitochondria. Open Biol 3: 120160. | ||
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Revision as of 15:49, 14 September 2013
| Hand SC, Patil Y (2013) Defense against ATP depletion during the energy-limited state of diapause. Mitochondr Physiol Network 18.08. |
Link:
MiP2013, Book of Abstracts Open Access
Event: MiP2013 Programme
Gastrula-stage embryos of Artemia franciscana (brine shrimp) undergo dramatic respiratory depression and developmental arrest upon release from the adult female as they enter a state of hypometabolism termed diapause [1]. Metabolism as measured by respiration rate declines by over 99% during entry into diapause across a 26-day time course [2]. The primary basis for the inhibition is a restriction of oxidative substrate to the mitochondrion that involves an orchestrated interplay at multiple enzymatic sites including trehalase, hexokinase, pyruvate kinase and pyruvate dehydrogenase [2].
While a substantial decrease in embryo ATP occurs during diapause, a significant amount of ATP remains [e.g., ATP:ADP ratio = 1.306 ± 0.036 (mean ± SE, N = 10)]. This observation is noteworthy when one considers that proton conductances of mitochondria isolated from diapause and post-diapause embryos are identical when compared as a function of the driving force (ΔΨ) [2]. Thus proton leak apparently is not downregulated during diapause, and as a consequence, mitochondrial ΔΨ is likely severely compromised because respiration of intact embryos is depressed far below that required to compensate for leak. Under such conditions, one would predict that the F1Fo-ATP synthase could reverse and fully deplete cellular ATP. Because ATP is not depleted, we predict that the F1Fo-ATP synthase is blocked during diapause by the F1-ATPase inhibitor protein IF1. This 9.6 kDa protein binds to the ATP synthase at the F1 catalytic domain and inhibits the hydrolytic activity of the enzyme under conditions where ΔΨ is low [3]. Further, acidic pH is known to promote the formation of the active dimeric state of IF1 and a stable complex with the enzyme [3]. It is likely that intracellular pH of A. franciscana embryos may decline during diapause as the metabolic depression phase progresses.
IF1 could potentially explain the conservation of adenylates in diapause. Affinity purification [4] and characterization of the ATP synthase from A. franciscana and its interaction with IF1 is underway.
• Keywords: Diapause, Inhibitor protein IF1
• O2k-Network Lab: US_LA Baton Rouge_Hand SC
Labels: MiParea: Respiration, Comparative MiP;environmental MiP, Developmental biology
Organism: Artemia
Preparation: Intact Organism"Intact Organism" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property., Homogenate, Isolated Mitochondria"Isolated Mitochondria" is not in the list (Intact organism, Intact organ, Permeabilized cells, Permeabilized tissue, Homogenate, Isolated mitochondria, SMP, Chloroplasts, Enzyme, Oxidase;biochemical oxidation, ...) of allowed values for the "Preparation" property., Enzyme Enzyme: Complex V; ATP Synthase"Complex V; ATP Synthase" is not in the list (Adenine nucleotide translocase, Complex I, Complex II;succinate dehydrogenase, Complex III, Complex IV;cytochrome c oxidase, Complex V;ATP synthase, Inner mt-membrane transporter, Marker enzyme, Supercomplex, TCA cycle and matrix dehydrogenases, ...) of allowed values for the "Enzyme" property. Regulation: ADP, ATP, mt-Membrane potential, pH Coupling state: LEAK, OXPHOS, ETS"ETS" is not in the list (LEAK, ROUTINE, OXPHOS, ET) of allowed values for the "Coupling states" property.
HRR: Oxygraph-2k
MiP2013, S03
Affiliations and author contributions
1 - Division of Cellular, Developmental, and Integrative Biology, Dept of Biol Sci, Louisiana State University, Baton Rouge, USA;
2 - Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, USA.
Email: [email protected]
Supported by NSF grant IOS-0920254 and NIH grant 2 RO1 DK046270-14A1
References
- Hand SC, Menze MA, Borcar A, Patil Y, Covi JA, Reynolds JA, Toner M (2011) Metabolic restructuring during energy-limited states: Insights from Artemia franciscana embryos and other animals. J Insect Physiol 57: 584-594.
- Patil Y, Marden B, Brand MD, Hand SC (2013) Metabolic downregulation and inhibition of carbohydrate catabolism during diapause in embryos of Artemia franciscana. Physiol Biochem Zool 86: 106-118.
- Bason JV, Runswick MJ, Fearnley IM, Walker JE (2011) Binding of the inhibitor protein IF1 to bovine F1-ATPase. J Mol Biol 406: 443-453.
- Runswick MJ, Bason JV, Montgomery MG, Robinson GC, Fearnley IM, Walker JE (2013) The affinity purification and characterization of ATP synthase complexes from mitochondria. Open Biol 3: 120160.
