Anmann 2005 FEBS J
| Anmann T, Eimre M, Kuznetsov AV, Andrienko T, Kaambre T, Sikk P, Seppet E, Tiivel T, Vendelin M, Seppet EK, Saks VA (2005) Calcium-induced contraction of sarcomeres changes the regulation of mitochondrial respiration in permeabilized cardiac cells. FEBS J 272:3145-61. |
Anmann T, Eimre M, Kuznetsov AV, Andrienko T, Kaambre T, Sikk P, Seppet E, Tiivel T, Vendelin M, Seppet EK, Saks VA (2005) FEBS J
Abstract: The relationships between cardiac cell structure and the regulation of mitochondrial respiration were studied by applying fluorescent confocal microscopy and analysing the kinetics of mitochondrial ADP-stimulated respiration, during calcium-induced contraction in permeabilized cardiomyocytes and myocardial fibers, and in their ‘ghost’ preparations (after selective myosin extraction). Up to 3 lm free calcium, in the presence of ATP, induced strong contraction of permeabilized cardiomyocytes with intact sarcomeres, accompanied by alterations in mitochondrial arrangement and a significant decrease in the apparent Km for exogenous ADP and ATP in the kinetics of mitochondrial respiration. The Vmax of respiration showed a moderate (50%) increase, with an optimum at 0.4 lm free calcium and a decrease at higher calcium concentrations. At high free-calcium concentrations, the direct flux of ADP from ATPases to mitochondria was diminished compared to that at low calcium levels. All of these effects were unrelated either to mitochondrial calcium overload or to mitochondrial permeability transition and were not observed in ‘ghost’ preparations after the selective extraction of myosin. Our results suggest that the structural changes transmitted from contractile apparatus to mitochondria modify localized restrictions of the diffusion of adenine nucleotides and thus may actively participate in the regulation of mitochondrial function, in addition to the metabolic signalling via the creatine kinase system. • Keywords: Adenine nucleotides, Calcium, Cardiomyocytes, Intracellular energetic units, Mitochondria
• O2k-Network Lab: EE Tartu Paju K, EE Tallinn Saks VA, FR Grenoble Saks VA, EE Tallinn Kaambre T
Labels:
Organism: Rat
Tissue;cell: Heart
Preparation: Permeabilized cells, Permeabilized tissue
Regulation: Ion;substrate transport Coupling state: OXPHOS, ET
HRR: Oxygraph-2k
