scholarly journals Evidence of a subunit 4 (subunit b) dimer in favor of the proximity of ATP synthase complexes in yeast inner mitochondrial membrane

1998 ◽  
Vol 1414 (1-2) ◽  
pp. 260-264 ◽  
Author(s):  
Christelle Spannagel ◽  
Jacques Vaillier ◽  
Geneviéve Arselin ◽  
Pierre-Vincent Graves ◽  
Xavier Grandier-Vazeille ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Inner Mitochondrial Membrane ◽  
A Subunit ◽  
Subunit B

scholarly journals High-Conductance Channel Formation in Yeast Mitochondria is Mediated by F-ATP Synthase e and g Subunits

2018 ◽  
Vol 50 (5) ◽  
pp. 1840-1855 ◽  
Author(s):  
Michela Carraro ◽  
Vanessa Checchetto ◽  
Geppo Sartori ◽  
Roza Kucharczyk ◽  
Jean-Paul di Rago ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Atp Synthase ◽  
Permeability Transition ◽  
Mitochondrial Morphology ◽  
In Vitro Mutagenesis ◽  
Inner Mitochondrial Membrane ◽  
Subunit B ◽  
Null Mutants ◽  
High Conductance

Background/Aims: The permeability transition pore (PTP) is an unselective, Ca2+-dependent high conductance channel of the inner mitochondrial membrane whose molecular identity has long remained a mystery. The most recent hypothesis is that pore formation involves the F-ATP synthase, which consistently generates Ca2+-activated channels. Available structures do not display obvious features that can accommodate a channel; thus, how the pore can form and whether its activity can be entirely assigned to F-ATP synthase is the matter of debate. In this study, we investigated the role of F-ATP synthase subunits e, g and b in PTP formation. Methods: Yeast null mutants for e, g and the first transmembrane (TM) α-helix of subunit b were generated and evaluated for mitochondrial morphology (electron microscopy), membrane potential (Rhodamine123 fluorescence) and respiration (Clark electrode). Homoplasmic C23S mutant of subunit a was generated by in vitro mutagenesis followed by biolistic transformation. F-ATP synthase assembly was evaluated by BN-PAGE analysis. Cu2+ treatment was used to induce the formation of F-ATP synthase dimers in the absence of e and g subunits. The electrophysiological properties of F-ATP synthase were assessed in planar lipid bilayers. Results: Null mutants for the subunits e and g display dimer formation upon Cu2+ treatment and show PTP-dependent mitochondrial Ca2+ release but not swelling. Cu2+ treatment causes formation of disulfide bridges between Cys23 of subunits a that stabilize dimers in absence of e and g subunits and favors the open state of wild-type F-ATP synthase channels. Absence of e and g subunits decreases conductance of the F-ATP synthase channel about tenfold. Ablation of the first TM of subunit b, which creates a distinct lateral domain with e and g, further affected channel activity. Conclusion: F-ATP synthase e, g and b subunits create a domain within the membrane that is critical for the generation of the high-conductance channel, thus is a prime candidate for PTP formation. Subunits e and g are only present in eukaryotes and may have evolved to confer this novel function to F-ATP synthase.

scholarly journals Dimer ribbons of ATP synthase shape the inner mitochondrial membrane

2008 ◽  
Vol 27 (7) ◽  
pp. 1154-1160 ◽  
Author(s):  
Mike Strauss ◽  
Götz Hofhaus ◽  
Rasmus R Schröder ◽  
Werner Kühlbrandt
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Inner Mitochondrial Membrane

Relationship of Subunit 8 of Yeast ATP Synthase and the Inner Mitochondrial Membrane

2008 ◽  
Vol 227 (3) ◽  
pp. 745-752
Author(s):  
Theo Papakonstantinou ◽  
Ruby H. P. Law ◽  
Stephen Manon ◽  
Rodney J. Devenish ◽  
Phillip Nagley
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Inner Mitochondrial Membrane ◽  
Relationship Of

scholarly journals Stepwise Assembly of Dimeric F1Fo-ATP Synthase in Mitochondria Involves the Small Fo-Subunits k and i

2010 ◽  
Vol 21 (9) ◽  
pp. 1494-1504 ◽  
Author(s):  
Karina Wagner ◽  
Inge Perschil ◽  
Christiane D. Fichter ◽  
Martin van der Laan
Keyword(s):  
Oxidative Phosphorylation ◽  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Intermediate Form ◽  
Membrane Domains ◽  
Inner Mitochondrial Membrane ◽  
F1fo Atp Synthase ◽  
Key Enzyme ◽  
Stepwise Assembly ◽  
Oligomeric Forms

F1Fo-ATP synthase is a key enzyme of oxidative phosphorylation that is localized in the inner membrane of mitochondria. It uses the energy stored in the proton gradient across the inner mitochondrial membrane to catalyze the synthesis of ATP from ADP and phosphate. Dimeric and higher oligomeric forms of ATP synthase have been observed in mitochondria from various organisms. Oligomerization of ATP synthase is critical for the morphology of the inner mitochondrial membrane because it supports the generation of tubular cristae membrane domains. Association of individual F1Fo-ATP synthase complexes is mediated by the membrane-embedded Fo-part. Several subunits were mapped to monomer-monomer-interfaces of yeast ATP synthase complexes, but only Su e (Atp21) and Su g (Atp20) have so far been identified as crucial for the formation of stable dimers. We show that two other small Fo-components, Su k (Atp19) and Su i (Atp18) are involved in the stepwise assembly of F1Fo-ATP synthase dimers and oligomers. We have identified an intermediate form of the ATP synthase dimer, which accumulates in the absence of Su i. Moreover, our data indicate that Su i facilitates the incorporation of newly synthesized subunits into ATP synthase complexes.

scholarly journals Evidence of the Proximity of ATP Synthase Subunits 6 (a) in the Inner Mitochondrial Membrane and in the Supramolecular Forms of Saccharomyces cerevisiae ATP Synthase

2011 ◽  
Vol 286 (41) ◽  
pp. 35477-35484 ◽  
Author(s):  
Jean Velours ◽  
Claire Stines-Chaumeil ◽  
Johan Habersetzer ◽  
Stéphane Chaignepain ◽  
Alain Dautant ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Transmembrane Helix ◽  
Disulfide Bridge ◽  
Cross Linking ◽  
Null Mutant ◽  
Terminal Part ◽  
Inner Mitochondrial Membrane ◽  
Membrane Spanning

The involvement of subunit 6 (a) in the interface between yeast ATP synthase monomers has been highlighted. Based on the formation of a disulfide bond and using the unique cysteine 23 as target, we show that two subunits 6 are close in the inner mitochondrial membrane and in the solubilized supramolecular forms of the yeast ATP synthase. In a null mutant devoid of supernumerary subunits e and g that are involved in the stabilization of ATP synthase dimers, ATP synthase monomers are close enough in the inner mitochondrial membrane to make a disulfide bridge between their subunits 6, and this proximity is maintained in detergent extract containing this enzyme. The cross-linking of cysteine 23 located in the N-terminal part of the first transmembrane helix of subunit 6 suggests that this membrane-spanning segment is in contact with its counterpart belonging to the ATP synthase monomer that faces it and participates in the monomer-monomer interface.

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