Hand 2013 Abstract MiP2013: Difference between revisions
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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=[[File:Hand photo.jpg|right|150px|Steven Hand]] [[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= | |event=MiPNet18.08_MiP2013 | ||
|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 Β± 0.036 (mean Β± 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 (ΞΞ¨) [2]. Thus proton leak apparently is not downregulated during diapause, and as a consequence, mitochondrial ΞΞ¨ 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 ΞΞ¨ 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. Β | While a substantial decrease in embryo ATP occurs during diapause, a significant amount of ATP remains [e.g., ATP:ADP ratio = 1.306 Β± 0.036 (mean Β± 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 (ΞΞ¨) [2]. Thus proton leak apparently is not downregulated during diapause, and as a consequence, mitochondrial ΞΞ¨ 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 ΞΞ¨ 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. Β | ||
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. | 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 | |keywords=Diapause, Inhibitor protein IF1 | ||
|mipnetlab=US_LA Baton Rouge_Hand SC | |mipnetlab=US_LA Baton Rouge_Hand SC | ||
}} | }} | ||
{{Labeling | {{Labeling | ||
| | |area=Respiration, Comparative MiP;environmental MiP, Developmental biology | ||
| | |organism=Artemia, Crustaceans | ||
|enzymes=Complex V; ATP | |preparations=Intact organism, Homogenate, Isolated mitochondria, Enzyme | ||
|topics=ATP | |enzymes=Complex V;ATP synthase | ||
|topics=ADP, ATP, mt-Membrane potential, pH | |||
|couplingstates=LEAK, OXPHOS, ET | |||
|pathways=N, S | |||
|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
|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; Β | 1 - Division of Cellular, Developmental, and Integrative Biology, Dept of Biol Sci, Louisiana State University, Baton Rouge, USA; Β | ||
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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 BiolΒ 406: 443-453. | # Bason JV, Runswick MJ, Fearnley IM, Walker JE (2011) Binding of the inhibitor protein IF1 to bovine F1-ATPase. J Mol BiolΒ 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.Β 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.Β Open Biol 3: 120160. | ||
__TOC__ |
Latest revision as of 14:30, 13 November 2017
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: MiPNet18.08_MiP2013
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 Β± 0.036 (mean Β± 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 (ΞΞ¨) [2]. Thus proton leak apparently is not downregulated during diapause, and as a consequence, mitochondrial ΞΞ¨ 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 ΞΞ¨ 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.
β’ Keywords: Diapause, Inhibitor protein IF1
β’ O2k-Network Lab: US_LA Baton Rouge_Hand SC
Labels: MiParea: Respiration, Comparative MiP;environmental MiP, Developmental biology
Organism: Artemia, Crustaceans
Preparation: Intact organism, Homogenate, Isolated mitochondria, Enzyme Enzyme: Complex V;ATP synthase Regulation: ADP, ATP, mt-Membrane potential, pH Coupling state: LEAK, OXPHOS, ET Pathway: N, S 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.