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Difference between revisions of "Kiss 2012 Abstract Bioblast"

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{{Abstract
{{Abstract
|title=Kiss G (2012) ..... Mitochondr Physiol Network 17.12.
|title=Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C (2012) The negative impact of alpha-ketoglutarate dehydrogenase complex deficiency on matrix substrate-level phosphorylation. Mitochondr Physiol Network 17.12.
|info=[[MiPNet17.12 Bioblast 2012|MiPNet17.12 Bioblast 2012 - Open Access]]
|info=[[MiPNet17.12 Bioblast 2012|MiPNet17.12 Bioblast 2012 - Open Access]]
|authors=Gergely Kiss(1), Csaba Konrad(1), Judit Doczi(1), Anatoly A. Starkov(2), Hibiki Kawamata(2), Giovanni Manfredi(2), Steven F. Zhang(2), Gary E. Gibson(3), M Flint Beal(2), Vera Adam-Vizi(1) and Christos Chinopoulos(1,2)
|authors=Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C
|year=2012
|year=2012
|event=[[Bioblast 2012]]
|event=[[Bioblast 2012]]
|abstract=The negative impact of alpha-ketoglutarate dehydrogenase complex deficiency on matrix substrate-level phosphorylation
|abstract=[[File:Kiss.G Bioblast2012 Abstract Photo(1).jpg|right|200px|Gergely Kiss]]


Objectives: provision of succinyl-CoA by the alpha-ketoglutarate dehydrogenase complex (KGDHC) is essential for generation of matrix ATP (or GTP) by substrate-level phosphorylation catalyzed by succinyl-CoA ligase. A decline in KGDHC activity has been associated with neurodegeneration.
'''Objectives:''' Provision of succinyl-CoA by the alpha-ketoglutarate dehydrogenase complex (KGDHC) is essential for generation of matrix ATP (or GTP) by substrate-level phosphorylation catalyzed by succinyl-CoA ligase. A decline in KGDHC activity has been associated with neurodegeneration.


Methods: mitochondrial phosphorylation was investigated in tissues of transgenic mice with deficiencies in KGDHC subunits.
'''Methods:''' Mitochondrial phosphorylation was investigated in tissues of transgenic mice with deficiencies in KGDHC subunits.


Results: we demonstrate ATP consumption in respiration-impaired isolated and in situ neuronal somal mitochondria from transgenic mice with a deficiency of either dihydrolipoyl succinyltransferase (DLST) or dihydrolipoyl dehydrogenase (DLD) exhibiting a 20-48% decrease in KGDHC activity. Import of ATP into the matrix of mitochondria from transgenic mice was attributed to a shift in the reversal potential of the adenine nucleotide translocase towards more negative values due to diminished matrix substrate-level phosphorylation, causing the translocase to reverse prematurely. Immunoreactivity of all three subunits of succinyl-CoA ligase and maximal enzymatic activity were unaffected in transgenic mice as compared to wild-type littermates. Therefore, decreased matrix substrate-level phosphorylation was due to diminished provision of succinyl-CoA. These results were further corroborated by the finding that mitochondria from wild-type mice respiring on substrates supporting substrate-level phosphorylation exhibited ~30% higher ADP-ATP exchange rates compared to those obtained from DLST+/- or DLD+/- littermates.  
'''Results:''' We demonstrate ATP consumption in respiration-impaired isolated and in situ neuronal somal mitochondria from transgenic mice with a deficiency of either dihydrolipoyl succinyltransferase (DLST) or dihydrolipoyl dehydrogenase (DLD) exhibiting a 20-48% decrease in KGDHC activity. Import of ATP into the matrix of mitochondria from transgenic mice was attributed to a shift in the reversal potential of the adenine nucleotide translocase towards more negative values due to diminished matrix substrate-level phosphorylation, causing the translocase to reverse prematurely. Immunoreactivity of all three subunits of succinyl-CoA ligase and maximal enzymatic activity were unaffected in transgenic mice as compared to wild-type littermates. Therefore, decreased matrix substrate-level phosphorylation was due to diminished provision of succinyl-CoA. These results were further corroborated by the finding that mitochondria from wild-type mice respiring on substrates supporting substrate-level phosphorylation exhibited ~30% higher ADP-ATP exchange rates compared to those obtained from DLST+/- or DLD+/- littermates.  


Conclusions: we propose that KGDHC-associated pathologies are subserved by the inability of respiration-impaired mitochondria to rely on “in-house” mitochondrial ATP reserves.
'''Conclusions:''' We propose that KGDHC-associated pathologies are subserved by the inability of respiration-impaired mitochondria to rely on “in-house” mitochondrial ATP reserves.
 
# [http://www.ncbi.nlm.nih.gov/pubmed/20207940 Chinopoulos C, Gerencser AA, Mandi M, Mathe K, Toeroecsik B, Doczi J, Turiak L, Kiss G, Konrad C, Vajda S, Vereczki V, Oh RJ, Adam-Vizi V (2010) Forward operation of adenine nucleotide translocase during F0F1-ATPase reversal: critical role of matrix substrate-level phosphorylation. FASEB J 24: 2405-2416. Open Access]
|keywords=Succinyl-CoA ligase, Adenine nucleotide translocase, F<sub>0</sub>-F<sub>1</sub> ATP synthase, Reversal potential
|mipnetlab=HU Budapest Chinopoulos C
|journal=Mitochondr Physiol Network
|journal=Mitochondr Physiol Network
|articletype=Abstract
|articletype=Abstract
}}
}}
{{Labeling|journal=Mitochondr Physiol Network
{{Labeling
|area=Respiration, Genetic knockout;overexpression
|organism=Mouse
|tissues=Nervous system, Liver
|preparations=Intact cells, Isolated mitochondria, Enzyme
|enzymes=Adenine nucleotide translocase, Complex V;ATP synthase, TCA cycle and matrix dehydrogenases
|injuries=Ischemia-reperfusion
|diseases=Aging;senescence
|topics=mt-Membrane potential, Substrate
|instruments=Oxygraph-2k, O2k-Fluorometer
|journal=Mitochondr Physiol Network
|articletype=Abstract
|articletype=Abstract
}}
}}
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== Affiliations and author contributions ==
== Affiliations and author contributions ==
Gergely  Kiss (1), Csaba  Konrad (1), Judit  Doczi (1), Anatoly A Starkov (2), Hibiki  Kawamata (2), Giovanni  Manfredi (2), Steven F Zhang (2), Gary E Gibson (3), M Flint Beal (2), Vera Adam-Vizi (1), Christos Chinopoulos (1,2)


(1) Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary
(1) Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; Email: [email protected]


(2) Weill Medical College Cornell University, New York, NY, 10021, USA
(2) Weill Medical College Cornell University, New York, NY, 10021, USA


(3) Weill Cornell Medical College/Burke Medical Research Institute, White Plains, NY, 10605, USA
(3) Weill Cornell Medical College/Burke Medical Research Institute, White Plains, NY, 10605, USA
== Figure 1 ==
[[File:Kiss.G Bioblast2012 Abstract Figure.jpg|600px|Reversal potential of adenine nucleotide translocase]]
Computational estimation of the reversal potential of adenine nucleotide translocase (Erev_ANT) and reversal potential of F<sub>0</sub>-F<sub>1</sub>ATPase (Erev_ATPase). A: ATPase forward, ANT forward; B: ATP reverse, ANT forward; C, C1, C2: ATPase reverse, ANT reverse; D: ATPase forward, ANT reverse. Black solid triangles represent Erev_ATPase; white solid triangles represent Erev_ANT. Values were computed for [ATP]out = 1.2 mM, [ADP]out = 10 μM, Pin = 0.01 M, n = 3.7 (2.7 plus 1 for the electrogenic ATP4-/ADP3- exchange of the ANT), pHi = 7.38, and pHo = 7.25. White open triangles represent Erev_ANT values computed
for [ATP]out = 1.4 mM, and all other parameters as above. Traces have been computed by Erev estimator; the software and instructions on how to use it can be downloaded [http://www.oxphos.org/index.php?option=com_remository&Itemid=40&func=fileinfo&id=74 here].


== Help ==
== Help ==
* [[Abstracts help]]
* [[MitoPedia: Terms and abbreviations]]
* [[MitoPedia Glossary: Terms and abbreviations]]

Latest revision as of 13:03, 16 June 2015

Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C (2012) The negative impact of alpha-ketoglutarate dehydrogenase complex deficiency on matrix substrate-level phosphorylation. Mitochondr Physiol Network 17.12.

Link: MiPNet17.12 Bioblast 2012 - Open Access

Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C (2012)

Event: Bioblast 2012

Gergely Kiss

Objectives: Provision of succinyl-CoA by the alpha-ketoglutarate dehydrogenase complex (KGDHC) is essential for generation of matrix ATP (or GTP) by substrate-level phosphorylation catalyzed by succinyl-CoA ligase. A decline in KGDHC activity has been associated with neurodegeneration.

Methods: Mitochondrial phosphorylation was investigated in tissues of transgenic mice with deficiencies in KGDHC subunits.

Results: We demonstrate ATP consumption in respiration-impaired isolated and in situ neuronal somal mitochondria from transgenic mice with a deficiency of either dihydrolipoyl succinyltransferase (DLST) or dihydrolipoyl dehydrogenase (DLD) exhibiting a 20-48% decrease in KGDHC activity. Import of ATP into the matrix of mitochondria from transgenic mice was attributed to a shift in the reversal potential of the adenine nucleotide translocase towards more negative values due to diminished matrix substrate-level phosphorylation, causing the translocase to reverse prematurely. Immunoreactivity of all three subunits of succinyl-CoA ligase and maximal enzymatic activity were unaffected in transgenic mice as compared to wild-type littermates. Therefore, decreased matrix substrate-level phosphorylation was due to diminished provision of succinyl-CoA. These results were further corroborated by the finding that mitochondria from wild-type mice respiring on substrates supporting substrate-level phosphorylation exhibited ~30% higher ADP-ATP exchange rates compared to those obtained from DLST+/- or DLD+/- littermates.

Conclusions: We propose that KGDHC-associated pathologies are subserved by the inability of respiration-impaired mitochondria to rely on “in-house” mitochondrial ATP reserves.

  1. Chinopoulos C, Gerencser AA, Mandi M, Mathe K, Toeroecsik B, Doczi J, Turiak L, Kiss G, Konrad C, Vajda S, Vereczki V, Oh RJ, Adam-Vizi V (2010) Forward operation of adenine nucleotide translocase during F0F1-ATPase reversal: critical role of matrix substrate-level phosphorylation. FASEB J 24: 2405-2416. Open Access

Keywords: Succinyl-CoA ligase, Adenine nucleotide translocase, F0-F1 ATP synthase, Reversal potential

O2k-Network Lab: HU Budapest Chinopoulos C


Labels: MiParea: Respiration, Genetic knockout;overexpression  Pathology: Aging;senescence  Stress:Ischemia-reperfusion  Organism: Mouse  Tissue;cell: Nervous system, Liver  Preparation: Intact cells, Isolated mitochondria, Enzyme  Enzyme: Adenine nucleotide translocase, Complex V;ATP synthase, TCA cycle and matrix dehydrogenases  Regulation: mt-Membrane potential, Substrate 


HRR: Oxygraph-2k, O2k-Fluorometer 




Affiliations and author contributions

Gergely Kiss (1), Csaba Konrad (1), Judit Doczi (1), Anatoly A Starkov (2), Hibiki Kawamata (2), Giovanni Manfredi (2), Steven F Zhang (2), Gary E Gibson (3), M Flint Beal (2), Vera Adam-Vizi (1), Christos Chinopoulos (1,2)

(1) Department of Medical Biochemistry, Semmelweis University, Budapest, 1094, Hungary; Email: [email protected]

(2) Weill Medical College Cornell University, New York, NY, 10021, USA

(3) Weill Cornell Medical College/Burke Medical Research Institute, White Plains, NY, 10605, USA

Figure 1

Reversal potential of adenine nucleotide translocase

Computational estimation of the reversal potential of adenine nucleotide translocase (Erev_ANT) and reversal potential of F0-F1ATPase (Erev_ATPase). A: ATPase forward, ANT forward; B: ATP reverse, ANT forward; C, C1, C2: ATPase reverse, ANT reverse; D: ATPase forward, ANT reverse. Black solid triangles represent Erev_ATPase; white solid triangles represent Erev_ANT. Values were computed for [ATP]out = 1.2 mM, [ADP]out = 10 μM, Pin = 0.01 M, n = 3.7 (2.7 plus 1 for the electrogenic ATP4-/ADP3- exchange of the ANT), pHi = 7.38, and pHo = 7.25. White open triangles represent Erev_ANT values computed for [ATP]out = 1.4 mM, and all other parameters as above. Traces have been computed by Erev estimator; the software and instructions on how to use it can be downloaded here.


Help