title: High efficiency of energy flux controls within mitochondrial interactosome in cardiac intracellular energetic units.
abstract: The aim of our study was to analyze a distribution of metabolic flux controls of all mitochondrial complexes of ATP-Synthasome and mitochondrial creatine kinase (MtCK) in situ in permeabilized cardiac cells. For this we used their specific inhibitors to measure flux control coefficients (C(vi)(JATP)) in two different systems: A) direct stimulation of respiration by ADP and B) activation of respiration by coupled MtCK reaction in the presence of MgATP and creatine. In isolated mitochondria the C(vi)(JATP) were for system A: Complex I - 0.19, Complex III - 0.06, Complex IV 0.18, adenine nucleotide translocase (ANT) - 0.11, ATP synthase - 0.01, Pi carrier - 0.20, and the sum of C(vi)(JATP) was 0.75. In the presence of 10mM creatine (system B) the C(vi)(JATP) were 0.38 for ANT and 0.80 for MtCK. In the permeabilized cardiomyocytes inhibitors had to be added in much higher final concentration, and the following values of C(vi)(JATP) were determined for condition A and B, respectively: Complex I - 0.20 and 0.64, Complex III - 0.41 and 0.40, Complex IV - 0.40 and 0.49, ANT - 0.20 and 0.92, ATP synthase - 0.065 and 0.38, Pi carrier - 0.06 and 0.06, MtCK 0.95. The sum of C(vi)(JATP) was 1.33 and 3.84, respectively. Thus, C(vi)(JATP) were specifically increased under conditions B only for steps involved in ADP turnover and for Complex I in permeabilized cardiomyocytes within Mitochondrial Interactosome, a supercomplex consisting of MtCK, ATP-Synthasome, voltage dependent anion channel associated with tubulin βII which restricts permeability of the mitochondrial outer membrane.
authors.affiliation: Laboratory of Bioenergetics, National Institute of Chemical Physics and Biophysics, Tallinn, Estonia.
authors.forename: Kersti
authors.initials: K
authors.lastname: Tepp
authors.forename: Igor
authors.initials: I
authors.lastname: Shevchuk
authors.forename: Vladimir
authors.initials: V
authors.lastname: Chekulayev
authors.forename: Natalja
authors.initials: N
authors.lastname: Timohhina
authors.forename: Andrey V
authors.initials: AV
authors.lastname: Kuznetsov
authors.forename: Rita
authors.initials: R
authors.lastname: Guzun
authors.forename: Valdur
authors.initials: V
authors.lastname: Saks
authors.forename: Tuuli
authors.initials: T
authors.lastname: Kaambre
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis / Q000378:metabolism; D000818:Animals; D000968:Antimycin A / Q000031:analogs & derivatives / Q000378:metabolism; D001278:Atractyloside / Q000031:analogs & derivatives / Q000378:metabolism; D019069:Cell Respiration / Q000502:physiology*; D052281:Creatine Kinase, Mitochondrial Form / Q000378:metabolism; D004139:Dinitrofluorobenzene / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000378:metabolism; D008297:Male; D008634:Mersalyl / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D000226:Mitochondrial ADP, ATP Translocases / Q000378:metabolism; D025261:Mitochondrial Proton-Translocating ATPases / Q000378:metabolism; D008962:Models, Theoretical; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D010101:Oxygen Consumption; D051381:Rats; D017208:Rats, Wistar; D012402:Rotenone / Q000378:metabolism; D012966:Sodium Cyanide / Q000378:metabolism; D014475:Uncoupling Agents / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D014475:Uncoupling Agents; D012402:Rotenone; C032456:antimycin; D001278:Atractyloside; D008634:Mersalyl; D000968:Antimycin A; D000255:Adenosine Triphosphate; D000226:Mitochondrial ADP, ATP Translocases; D004139:Dinitrofluorobenzene; D052281:Creatine Kinase, Mitochondrial Form; D025261:Mitochondrial Proton-Translocating ATPases; D012966:Sodium Cyanide; C003853:carboxyatractyloside