Mitochondrial membrane potential is dependent on the oligomeric state of F1F0-ATP synthase supracomplexes.
The F1F0-ATP synthase in mitochondria, in addition to its function in energy transduction, has a structural role in determining cristae morphology. This depends on its ability to form dimeric and higher oligomeric supracomplexes. Here we show that mutants of the dimer-specific subunits e and g, which destabilize dimeric and oligomeric F1F0-ATP synthase supracomplexes, have a decreased mitochondrial membrane potential delta psi. The degree of destabilization correlated with the reduction of the membrane potential. The enzymatic activities of F1F0-ATP synthase and cytochrome c oxidase, maximal respiration rate, coupling of oxidative phosphorylation, and tubular mitochondrial morphology were not affected or only to a minor extent. In mutants lacking one or two coiled-coil domains of subunit e, the reduction of the mitochondrial membrane potential was not due to loss of mitochondrial DNA, a reduced capacity of oxidative phosphorylation, or to altered cristae morphology. We propose a role for the supracomplexes of the F1F0-ATP synthase in organizing microdomains within the inner membrane, ensuring optimal bioenergetic competence of mitochondria.
Bornhövd
Carsten
C
Adolf-Butenandt-Institut für Physiologische Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5, 81377 München, Germany.
Vogel
Frank
F
Neupert
Walter
W
Reichert
Andreas S
AS
D003580:Cytochromes / Q000378:metabolism; D004247:DNA / Q000737:chemistry; D019281:Dimerization; D008564:Membrane Potentials; D008928:Mitochondria / Q000378:metabolism*; D051336:Mitochondrial Membranes / Q000378:metabolism*; D025261:Mitochondrial Proton-Translocating ATPases / Q000737:chemistry*; D010100:Oxygen / Q000378:metabolism; D010641:Phenotype; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry
D003580:Cytochromes; D029701:Saccharomyces cerevisiae Proteins; D004247:DNA; C474451:F1F0-ATP synthase; D025261:Mitochondrial Proton-Translocating ATPases; D010100:Oxygen