The composition of plant mitochondrial supercomplexes changes with oxygen availability.
Respiratory supercomplexes are large protein structures formed by various enzyme complexes of the mitochondrial electron transport chain. Using native gel electrophoresis and activity staining, differential regulation of complex activity within the supercomplexes was investigated. During prolonged hypoxia, complex I activity within supercomplexes diminished, whereas the activity of the individual complex I-monomer increased. Concomitantly, an increased activity was observed during hypoxia for complex IV in the smaller supercomplexes that do not contain complex I. These changes in complex activity within supercomplexes reverted again during recovery from the hypoxic treatment. Acidification of the mitochondrial matrix induced similar changes in complex activity within the supercomplexes. It is suggested that the increased activity of the small supercomplex III(2)+IV can be explained by the dissociation of complex I from the large supercomplexes. This is discussed to be part of a mechanism regulating the involvement of the alternative NADH dehydrogenases, known to be activated by low pH, and complex I, which is inhibited by low pH. It is concluded that the activity of complexes within supercomplexes can be regulated depending on the oxygen status and the pH of the mitochondrial matrix.
Max Planck Institute of Molecular Plant Physiology, Energy Metabolism Research Group, Am Mühlenberg 1, D-14476, Potsdam, Germany.
Santiago J
SJ
Ramírez-Aguilar
Mandy
M
Keuthe
Marcio
M
Rocha
Vadim V
VV
Fedyaev
Katharina
K
Kramp
Kapuganti J
KJ
Gupta
Allan G
AG
Rasmusson
Waltraud X
WX
Schulze
Joost T
JT
van Dongen
D015687:Cell Hypoxia / Q000502:physiology; D042967:Electron Transport Complex I / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D010944:Plants / Q000201:enzymology* / Q000378:metabolism*; D011198:Solanum tuberosum / Q000378:metabolism; D053719:Tandem Mass Spectrometry
D009097:Multienzyme Complexes; D010940:Plant Proteins; D003576:Electron Transport Complex IV; D042967:Electron Transport Complex I