ATP synthase oligomerization: From the enzyme models to the mitochondrial morphology

2013 ◽  
Vol 45 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Johan Habersetzer ◽  
Widade Ziani ◽  
Isabelle Larrieu ◽  
Claire Stines-Chaumeil ◽  
Marie-France Giraud ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Morphology ◽  
Enzyme Models

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 Functional Analysis of Subunit e of the F1Fo-ATP Synthase of the Yeast Saccharomyces cerevisiae: Importance of the N-Terminal Membrane Anchor Region

2005 ◽  
Vol 4 (2) ◽  
pp. 346-355 ◽  
Author(s):  
Valerie Everard-Gigot ◽  
Cory D. Dunn ◽  
Brigid M. Dolan ◽  
Susanne Brunner ◽  
Robert E. Jensen ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Atp Synthase ◽  
Mitochondrial Membrane ◽  
Critical Role ◽  
Coiled Coil ◽  
Mitochondrial Morphology ◽  
Hydrophobic Region ◽  
Inner Membrane ◽  
E Protein ◽  
Subunit E

ABSTRACT Mitochondrial F1Fo-ATP synthase complexes do not exist as physically independent entities but rather form dimeric and possibly oligomeric complexes in the inner mitochondrial membrane. Stable dimerization of two F1Fo-monomeric complexes involves the physical association of two membrane-embedded Fo-sectors. Previously, formation of the ATP synthase dimeric-oligomeric network was demonstrated to play a critical role in modulating the morphology of the mitochondrial inner membrane. In Saccharomyces cerevisiae, subunit e (Su e) of the Fo-sector plays a central role in supporting ATP synthase dimerization. The Su e protein is anchored to the inner membrane via a hydrophobic region located at its N-terminal end. The hydrophilic C-terminal region of Su e resides in the intermembrane space and contains a conserved coiled-coil motif. In the present study, we focused on characterizing the importance of these regions for the function of Su e. We created a number of C-terminal-truncated derivatives of the Su e protein and expressed them in the Su e null yeast mutant. Mitochondria were isolated from the resulting transformant strains, and a number of functions of Su e were analyzed. Our results indicate that the N-terminal hydrophobic region plays important roles in the Su e-dependent processes of mitochondrial DNA maintenance, modulation of mitochondrial morphology, and stabilization of the dimer-specific Fo subunits, subunits g and k. Furthermore, we show that the C-terminal coiled-coil region of Su e functions to stabilize the dimeric form of detergent-solubilized ATP synthase complexes. Finally, we propose a model to explain how Su e supports the assembly of the ATP synthase dimers-oligomers in the mitochondrial membrane.

scholarly journals The f subunit of human ATP synthase is essential for normal mitochondrial morphology and permeability transition

Cell Reports ◽  
2021 ◽  
Vol 35 (6) ◽  
pp. 109111
Author(s):  
Chiara Galber ◽  
Giovanni Minervini ◽  
Giuseppe Cannino ◽  
Francesco Boldrin ◽  
Valeria Petronilli ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Permeability Transition ◽  
Mitochondrial Morphology

scholarly journals Identification of cryptic subunits from an apicomplexan ATP synthase

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Diego Huet ◽  
Esther Rajendran ◽  
Giel G van Dooren ◽  
Sebastian Lourido
Keyword(s):  
Oxygen Consumption ◽  
Toxoplasma Gondii ◽  
Atp Synthase ◽  
Proton Gradient ◽  
Mitochondrial Morphology ◽  
Apicomplexan Parasites ◽  
Essential Component ◽  
Mitochondrial Atp Synthase ◽  
Form Part ◽  
Genes Encoding

The mitochondrial ATP synthase is a macromolecular motor that uses the proton gradient to generate ATP. Proper ATP synthase function requires a stator linking the catalytic and rotary portions of the complex. However, sequence-based searches fail to identify genes encoding stator subunits in apicomplexan parasites like Toxoplasma gondii or the related organisms that cause malaria. Here, we identify 11 previously unknown subunits from the Toxoplasma ATP synthase, which lack homologs outside the phylum. Modeling suggests that two of them, ICAP2 and ICAP18, are distantly related to mammalian stator subunits. Our analysis shows that both proteins form part of the ATP synthase complex. Depletion of ICAP2 leads to aberrant mitochondrial morphology, decreased oxygen consumption, and disassembly of the complex, consistent with its role as an essential component of the Toxoplasma ATP synthase. Our findings highlight divergent features of the central metabolic machinery in apicomplexans, which may reveal new therapeutic opportunities.

scholarly journals Superresolution microscopy reveals spatial separation of UCP4 and F0F1-ATP synthase in neuronal mitochondria

2014 ◽  
Vol 112 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Enrico Klotzsch ◽  
Alina Smorodchenko ◽  
Lukas Löfler ◽  
Rudolf Moldzio ◽  
Elena Parkinson ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Chemical Potential ◽  
Uncoupling Protein ◽  
Spatial Separation ◽  
Proton Gradient ◽  
Mitochondrial Morphology ◽  
Proton Pumps ◽  
Inner Mitochondrial Membrane ◽  
Voltage Dependent Anion Channel ◽  
Primary Mouse

Because different proteins compete for the proton gradient across the inner mitochondrial membrane, an efficient mechanism is required for allocation of associated chemical potential to the distinct demands, such as ATP production, thermogenesis, regulation of reactive oxygen species (ROS), etc. Here, we used the superresolution technique dSTORM (direct stochastic optical reconstruction microscopy) to visualize several mitochondrial proteins in primary mouse neurons and test the hypothesis that uncoupling protein 4 (UCP4) and F0F1-ATP synthase are spatially separated to eliminate competition for the proton motive force. We found that UCP4, F0F1-ATP synthase, and the mitochondrial marker voltage-dependent anion channel (VDAC) have various expression levels in different mitochondria, supporting the hypothesis of mitochondrial heterogeneity. Our experimental results further revealed that UCP4 is preferentially localized in close vicinity to VDAC, presumably at the inner boundary membrane, whereas F0F1-ATP synthase is more centrally located at the cristae membrane. The data suggest that UCP4 cannot compete for protons because of its spatial separation from both the proton pumps and the ATP synthase. Thus, mitochondrial morphology precludes UCP4 from acting as an uncoupler of oxidative phosphorylation but is consistent with the view that UCP4 may dissipate the excessive proton gradient, which is usually associated with ROS production.

scholarly journals Threshold of heteroplasmic truncating MT-ATP6 mutation in reprogramming, Notch hyperactivation and motor neuron metabolism

2021 ◽  
Author(s):  
Sebastian Kenvin ◽  
Ruben Torregrosa-Muñumer ◽  
Marco Reidelbach ◽  
Jana Pennonen ◽  
Jeremi J Turkia ◽  
...  
Keyword(s):  
Cell Fate ◽  
Atp Synthase ◽  
Motor Neurons ◽  
Mitochondrial Diseases ◽  
Leigh Syndrome ◽  
Cellular Reprogramming ◽  
Patient Specific ◽  
Mitochondrial Morphology ◽  
Cell Fate Decisions ◽  
Truncating Mutation

Abstract Mutations in mitochondrial DNA encoded subunit of ATP synthase, MT-ATP6, are frequent causes of neurological mitochondrial diseases with a range of phenotypes from Leigh syndrome and NARP to ataxias and neuropathies. Here we investigated the functional consequences of an unusual heteroplasmic truncating mutation m.9154C>T in MT-ATP6, which caused peripheral neuropathy, ataxia and IgA nephropathy. ATP synthase not only generates cellular ATP, but its dimerization is required for mitochondrial cristae formation. Accordingly, the MT-ATP6 truncating mutation impaired the assembly of ATP synthase and disrupted cristae morphology, supporting our molecular dynamics simulations that predicted destabilized a/c subunit subcomplex. Next, we modeled the effects of the truncating mutation using patient-specific induced pluripotent stem cells. Unexpectedly, depending on mutation heteroplasmy level, the truncation showed multiple threshold effects in cellular reprogramming, neurogenesis and in metabolism of mature motor neurons (MN). Interestingly, MN differentiation beyond progenitor stage was impaired by Notch hyperactivation in the MT-ATP6 mutant, but not by rotenone-induced inhibition of mitochondrial respiration, suggesting that altered mitochondrial morphology contributed to Notch hyperactivation. Finally, we also identified a lower mutation threshold for a metabolic shift in mature MN, affecting lactate utilization, which may be relevant for understanding the mechanisms of mitochondrial involvement in peripheral motor neuropathies. These results establish a critical and disease-relevant role for ATP synthase in human cell fate decisions and neuronal metabolism.

scholarly journals Yeast Cells Lacking the Mitochondrial Gene Encoding the ATP Synthase Subunit 6 Exhibit a Selective Loss of Complex IV and Unusual Mitochondrial Morphology

2007 ◽  
Vol 282 (15) ◽  
pp. 10853-10864 ◽  
Author(s):  
Malgorzata Rak ◽  
Emmanuel Tetaud ◽  
François Godard ◽  
Isabelle Sagot ◽  
Bénédicte Salin ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Gene ◽  
Yeast Cells ◽  
Mitochondrial Morphology ◽  
Gene Encoding ◽  
Complex Iv ◽  
Selective Loss

scholarly journals Identification of cryptic stator subunits from an apicomplexan ATP synthase

2018 ◽  
Author(s):  
Diego Huet ◽  
Esther Rajendran ◽  
Giel G. Van Dooren ◽  
Sebastian Lourido
Keyword(s):  
Oxygen Consumption ◽  
Atp Synthase ◽  
Hidden Markov ◽  
Mitochondrial Morphology ◽  
Markov Modeling ◽  
Apicomplexan Parasites ◽  
Hidden Markov Modeling ◽  
Mitochondrial Atp Synthase ◽  
Form Part ◽  
Genes Encoding

ABSTRACTThe mitochondrial ATP synthase is a macromolecular motor that uses the proton gradient to generate ATP. Proper ATP synthase function requires a stator linking the catalytic and rotary portions of the complex. However, sequence-based searches fail to identify genes encoding stator subunits in apicomplexan parasites like Toxoplasma gondii or the related organisms that cause malaria. Here, we identify 11 previously unknown subunits from the Toxoplasma ATP synthase, which lack homologs outside the phylum. Hidden Markov modeling suggests that two of them—ICAP2 and ICAP18—share distant homology with mammalian stator subunits. Our analysis shows that both proteins form part of the ATP synthase complex. Depletion of ICAP2 leads to aberrant mitochondrial morphology, decreased oxygen consumption, and disassembly of the complex, consistent with its role as an essential component of the Toxoplasma ATP synthase. Our findings highlight divergent features of the central metabolic machinery in apicomplexans, which may reveal new therapeutic opportunities.

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