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Kiss 2012 Abstract Bioblast

From Bioblast
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 โ€œin-houseโ€ 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

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

โ€ข O2k-Network Lab: HU Budapest Chinopoulos C


Labels: MiParea: Respiration, Genetic knockout;overexpression  Pathology: Aging; senescence"Aging; senescence" is not in the list (Aging;senescence, Alzheimer's, Autism, Cancer, Cardiovascular, COPD, Diabetes, Inherited, Infectious, Myopathy, ...) of allowed values for the "Diseases" property.  Stress:Hypoxia, Ischemia-Reperfusion; Preservation"Ischemia-Reperfusion; Preservation" is not in the list (Cell death, Cryopreservation, Ischemia-reperfusion, Permeability transition, Oxidative stress;RONS, Temperature, Hypoxia, Mitochondrial disease) of allowed values for the "Stress" property.  Organism: Mouse  Tissue;cell: Nervous system, Liver  Preparation: Intact cells, 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: Adenine Nucleotide Translocase"Adenine Nucleotide Translocase" 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., 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., TCA Cycle and Matrix Dehydrogenases"TCA Cycle and Matrix Dehydrogenases" 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: mt-Membrane potential, Substrate 


HRR: Oxygraph-2k, Fluorometry"Fluorometry" is not in the list (Oxygraph-2k, TIP2k, O2k-Fluorometer, pH, NO, TPP, Ca, O2k-Spectrophotometer, O2k-Manual, O2k-Protocol, ...) of allowed values for the "Instrument and method" property. 




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 ฮผM, 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.


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