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Sobti M, Ishmukhametov R, Bouwer JC, Ayer A, Suarna C, Smith NJ, Christie M, Stocker R, Duncan TM, Stewart AG. Cryo-EM reveals distinct conformations of E. coli ATP synthase on exposure to ATP. eLife 2019; 8:e43864. [PMID: 30912741 PMCID: PMC6449082 DOI: 10.7554/elife.43864] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 03/25/2019] [Indexed: 12/13/2022] Open
Abstract
ATP synthase produces the majority of cellular energy in most cells. We have previously reported cryo-EM maps of autoinhibited E. coli ATP synthase imaged without addition of nucleotide (Sobti et al. 2016), indicating that the subunit ε engages the α, β and γ subunits to lock the enzyme and prevent functional rotation. Here we present multiple cryo-EM reconstructions of the enzyme frozen after the addition of MgATP to identify the changes that occur when this ε inhibition is removed. The maps generated show that, after exposure to MgATP, E. coli ATP synthase adopts a different conformation with a catalytic subunit changing conformation substantially and the ε C-terminal domain transitioning via an intermediate 'half-up' state to a condensed 'down' state. This work provides direct evidence for unique conformational states that occur in E. coli ATP synthase when ATP binding prevents the ε C-terminal domain from entering the inhibitory 'up' state.
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Affiliation(s)
- Meghna Sobti
- Molecular, Structural and Computational Biology DivisionThe Victor Chang Cardiac Research InstituteDarlinghurstAustralia
- St Vincent’s Clinical School, Faculty of MedicineUNSW SydneySydneyAustralia
| | - Robert Ishmukhametov
- Department of Physics, Clarendon LaboratoryUniversity of OxfordOxfordUnited Kingdom
| | - James C Bouwer
- Molecular HorizonsThe University of WollongongWollongongAustralia
| | - Anita Ayer
- St Vincent’s Clinical School, Faculty of MedicineUNSW SydneySydneyAustralia
- Vascular Biology DivisionVictor Chang Cardiac Research InstituteDarlinghurstAustralia
| | - Cacang Suarna
- Vascular Biology DivisionVictor Chang Cardiac Research InstituteDarlinghurstAustralia
| | - Nicola J Smith
- St Vincent’s Clinical School, Faculty of MedicineUNSW SydneySydneyAustralia
- Molecular Cardiology and Biophysics DivisionVictor Chang Cardiac Research InstituteDarlinghurstAustralia
| | - Mary Christie
- Molecular, Structural and Computational Biology DivisionThe Victor Chang Cardiac Research InstituteDarlinghurstAustralia
- St Vincent’s Clinical School, Faculty of MedicineUNSW SydneySydneyAustralia
| | - Roland Stocker
- St Vincent’s Clinical School, Faculty of MedicineUNSW SydneySydneyAustralia
- Vascular Biology DivisionVictor Chang Cardiac Research InstituteDarlinghurstAustralia
| | - Thomas M Duncan
- Department of Biochemistry & Molecular BiologySUNY Upstate Medical UniversitySyracuse, NYUnited States
| | - Alastair G Stewart
- Molecular, Structural and Computational Biology DivisionThe Victor Chang Cardiac Research InstituteDarlinghurstAustralia
- St Vincent’s Clinical School, Faculty of MedicineUNSW SydneySydneyAustralia
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Abstract
F1Fo ATP synthases produce most of the ATP in the cell. F-type ATP synthases have been investigated for more than 50 years, but a full understanding of their molecular mechanisms has become possible only with the recent structures of complete, functionally competent complexes determined by electron cryo-microscopy (cryo-EM). High-resolution cryo-EM structures offer a wealth of unexpected new insights. The catalytic F1 head rotates with the central γ-subunit for the first part of each ATP-generating power stroke. Joint rotation is enabled by subunit δ/OSCP acting as a flexible hinge between F1 and the peripheral stalk. Subunit a conducts protons to and from the c-ring rotor through two conserved aqueous channels. The channels are separated by ∼6 Å in the hydrophobic core of Fo, resulting in a strong local field that generates torque to drive rotary catalysis in F1. The structure of the chloroplast F1Fo complex explains how ATPase activity is turned off at night by a redox switch. Structures of mitochondrial ATP synthase dimers indicate how they shape the inner membrane cristae. The new cryo-EM structures complete our picture of the ATP synthases and reveal the unique mechanism by which they transform an electrochemical membrane potential into biologically useful chemical energy.
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Affiliation(s)
- Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt, Germany;
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The structure of the catalytic domain of the ATP synthase from Mycobacterium smegmatis is a target for developing antitubercular drugs. Proc Natl Acad Sci U S A 2019; 116:4206-4211. [PMID: 30683723 DOI: 10.1073/pnas.1817615116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The crystal structure of the F1-catalytic domain of the adenosine triphosphate (ATP) synthase has been determined from Mycobacterium smegmatis which hydrolyzes ATP very poorly. The structure of the α3β3-component of the catalytic domain is similar to those in active F1-ATPases in Escherichia coli and Geobacillus stearothermophilus However, its ε-subunit differs from those in these two active bacterial F1-ATPases as an ATP molecule is not bound to the two α-helices forming its C-terminal domain, probably because they are shorter than those in active enzymes and they lack an amino acid that contributes to the ATP binding site in active enzymes. In E. coli and G. stearothermophilus, the α-helices adopt an "up" state where the α-helices enter the α3β3-domain and prevent the rotor from turning. The mycobacterial F1-ATPase is most similar to the F1-ATPase from Caldalkalibacillus thermarum, which also hydrolyzes ATP poorly. The βE-subunits in both enzymes are in the usual "open" conformation but appear to be occupied uniquely by the combination of an adenosine 5'-diphosphate molecule with no magnesium ion plus phosphate. This occupation is consistent with the finding that their rotors have been arrested at the same point in their rotary catalytic cycles. These bound hydrolytic products are probably the basis of the inhibition of ATP hydrolysis. It can be envisaged that specific as yet unidentified small molecules might bind to the F1 domain in Mycobacterium tuberculosis, prevent ATP synthesis, and inhibit the growth of the pathogen.
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Gahura O, Panicucci B, Váchová H, Walker JE, Zíková A. Inhibition of F 1 -ATPase from Trypanosoma brucei by its regulatory protein inhibitor TbIF 1. FEBS J 2018; 285:4413-4423. [PMID: 30288927 DOI: 10.1111/febs.14672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 09/19/2018] [Accepted: 10/01/2018] [Indexed: 12/30/2022]
Abstract
Hydrolysis of ATP by the mitochondrial F-ATPase is inhibited by a protein called IF1 . In the parasitic flagellate, Trypanosoma brucei, this protein, known as TbIF1 , is expressed exclusively in the procyclic stage, where the F-ATPase is synthesizing ATP. In the bloodstream stage, where TbIF1 is absent, the F-ATPase hydrolyzes ATP made by glycolysis and compensates for the absence of a proton pumping respiratory chain by translocating protons into the intermembrane space, thereby maintaining the essential mitochondrial membrane potential. We have defined regions and amino acid residues of TbIF1 that are required for its inhibitory activity by analyzing the binding of several modified recombinant inhibitors to F1 -ATPase isolated from the procyclic stage of T. brucei. Kinetic measurements revealed that the C-terminal portion of TbIF1 facilitates homodimerization, but it is not required for the inhibitory activity, similar to the bovine and yeast orthologs. However, in contrast to bovine IF1 , the inhibitory capacity of the C-terminally truncated TbIF1 diminishes with decreasing pH, similar to full length TbIF1 . This effect does not involve the dimerization of active dimers to form inactive tetramers. Over a wide pH range, the full length and C-terminally truncated TbIF1 form dimers and monomers, respectively. TbIF1 has no effect on bovine F1 -ATPase, and this difference in the mechanism of regulation of the F-ATPase between the host and the parasite could be exploited in the design of drugs to combat human and animal African trypanosomiases.
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Affiliation(s)
- Ondřej Gahura
- Institute of Parasitology, Biology Centre Czech Academy of Science, České Budějovice, Czech Republic
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, UK
| | - Brian Panicucci
- Institute of Parasitology, Biology Centre Czech Academy of Science, České Budějovice, Czech Republic
| | - Hana Váchová
- Institute of Parasitology, Biology Centre Czech Academy of Science, České Budějovice, Czech Republic
| | - John E Walker
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, UK
| | - Alena Zíková
- Institute of Parasitology, Biology Centre Czech Academy of Science, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
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55
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MYC Induces a Hybrid Energetics Program Early in Cell Reprogramming. Stem Cell Reports 2018; 11:1479-1492. [PMID: 30472011 PMCID: PMC6294174 DOI: 10.1016/j.stemcr.2018.10.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/25/2018] [Accepted: 10/25/2018] [Indexed: 01/07/2023] Open
Abstract
Cell reprogramming is thought to be associated with a full metabolic switch from an oxidative- to a glycolytic-based metabolism. However, neither the dynamics nor the factors controlling this metabolic switch are fully understood. By using cellular, biochemical, protein array, metabolomic, and respirometry analyses, we found that c-MYC establishes a robust bivalent energetics program early in cell reprogramming. Cells prone to undergo reprogramming exhibit high mitochondrial membrane potential and display a hybrid metabolism. We conclude that MYC proteins orchestrate a rewiring of somatic cell metabolism early in cell reprogramming, whereby somatic cells acquire the phenotypic plasticity necessary for their transition to pluripotency in response to either intrinsic or external cues. Endogenous MYC biological activity is necessary for cell reprogramming MYC drives mitochondrial fission early in cell reprogramming MYC establishes a bivalent energetics state necessary for cell reprogramming MYC polarizes mitochondria, poising cells for reprogramming
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Mendoza-Hoffmann F, Zarco-Zavala M, Ortega R, García-Trejo JJ. Control of rotation of the F1FO-ATP synthase nanomotor by an inhibitory α-helix from unfolded ε or intrinsically disordered ζ and IF1 proteins. J Bioenerg Biomembr 2018; 50:403-424. [DOI: 10.1007/s10863-018-9773-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/13/2018] [Indexed: 12/14/2022]
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Zorova LD, Popkov VA, Plotnikov EY, Silachev DN, Pevzner IB, Jankauskas SS, Babenko VA, Zorov SD, Balakireva AV, Juhaszova M, Sollott SJ, Zorov DB. Mitochondrial membrane potential. Anal Biochem 2018; 552:50-59. [PMID: 28711444 PMCID: PMC5792320 DOI: 10.1016/j.ab.2017.07.009] [Citation(s) in RCA: 1060] [Impact Index Per Article: 176.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 01/13/2023]
Abstract
The mitochondrial membrane potential (ΔΨm) generated by proton pumps (Complexes I, III and IV) is an essential component in the process of energy storage during oxidative phosphorylation. Together with the proton gradient (ΔpH), ΔΨm forms the transmembrane potential of hydrogen ions which is harnessed to make ATP. The levels of ΔΨm and ATP in the cell are kept relatively stable although there are limited fluctuations of both these factors that can occur reflecting normal physiological activity. However, sustained changes in both factors may be deleterious. A long-lasting drop or rise of ΔΨm vs normal levels may induce unwanted loss of cell viability and be a cause of various pathologies. Among other factors, ΔΨm plays a key role in mitochondrial homeostasis through selective elimination of dysfunctional mitochondria. It is also a driving force for transport of ions (other than H+) and proteins which are necessary for healthy mitochondrial functioning. We propose additional potential mechanisms for which ΔΨm is essential for maintenance of cellular health and viability and provide recommendations how to accurately measure ΔΨm in a cell and discuss potential sources of artifacts.
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Affiliation(s)
- Ljubava D Zorova
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; International Laser Center, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Vasily A Popkov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Egor Y Plotnikov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Denis N Silachev
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Irina B Pevzner
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Stanislovas S Jankauskas
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Valentina A Babenko
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Savva D Zorov
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russian Federation
| | - Anastasia V Balakireva
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russian Federation
| | - Magdalena Juhaszova
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Dmitry B Zorov
- A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russian Federation; Laboratory of Cardiovascular Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA.
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58
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Nesci S, Trombetti F, Ventrella V, Pagliarani A. From the Ca 2+-activated F 1F O-ATPase to the mitochondrial permeability transition pore: an overview. Biochimie 2018; 152:85-93. [PMID: 29964086 DOI: 10.1016/j.biochi.2018.06.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 06/26/2018] [Indexed: 01/02/2023]
Abstract
Based on recent advances on the Ca2+-activated F1FO-ATPase features, a novel multistep mechanism involving the mitochondrial F1FO complex in the formation and opening of the still enigmatic mitochondrial permeability transition pore (MPTP), is proposed. MPTP opening makes the inner mitochondrial membrane (IMM) permeable to ions and solutes and, through cascade events, addresses cell fate to death. Since MPTP forms when matrix Ca2+ concentration rises and ATP is hydrolyzed by the F1FO-ATPase, conformational changes, triggered by Ca2+ insertion in F1, may be transmitted to FO and locally modify the IMM curvature. These events would cause F1FO-ATPase dimer dissociation and MPTP opening.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Fabiana Trombetti
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Vittoria Ventrella
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy
| | - Alessandra Pagliarani
- Department of Veterinary Medical Sciences, University of Bologna, Via Tolara di Sopra 50, 40064, Ozzano Emilia, BO, Italy.
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59
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Hardonnière K, Lagadic-Gossmann D. ATPase inhibitory factor 1 (IF1): a novel player in pollutant-related diseases? CURRENT OPINION IN TOXICOLOGY 2018. [DOI: 10.1016/j.cotox.2017.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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60
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Esparza-Moltó PB, Cuezva JM. The Role of Mitochondrial H +-ATP Synthase in Cancer. Front Oncol 2018; 8:53. [PMID: 29564224 PMCID: PMC5845864 DOI: 10.3389/fonc.2018.00053] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 02/20/2018] [Indexed: 01/23/2023] Open
Abstract
Cancer cells reprogram energy metabolism by boosting aerobic glycolysis as a main pathway for the provision of metabolic energy and of precursors for anabolic purposes. Accordingly, the relative expression of the catalytic subunit of the mitochondrial H+-ATP synthase—the core hub of oxidative phosphorylation—is downregulated in human carcinomas when compared with its expression in normal tissues. Moreover, some prevalent carcinomas also upregulate the ATPase inhibitory factor 1 (IF1), which is the physiological inhibitor of the H+-ATP synthase. IF1 overexpression, both in cells in culture and in tissue-specific mouse models, is sufficient to reprogram energy metabolism to an enhanced glycolysis by limiting ATP production by the H+-ATP synthase. Furthermore, the IF1-mediated inhibition of the H+-ATP synthase promotes the production of mitochondrial ROS (mtROS). mtROS modulate signaling pathways favoring cellular proliferation and invasion, the activation of antioxidant defenses, resistance to cell death, and modulation of the tissue immune response, favoring the acquisition of several cancer traits. Consistently, IF1 expression is an independent marker of cancer prognosis. By contrast, inhibition of the H+-ATP synthase by α-ketoglutarate and the oncometabolite 2-hydroxyglutarate, reduces mTOR signaling, suppresses cancer cell growth, and contributes to lifespan extension in several model organisms. Hence, the H+-ATP synthase appears as a conserved hub in mitochondria-to-nucleus signaling controlling cell fate. Unraveling the molecular mechanisms responsible for IF1 upregulation in cancer and the signaling cascades that are modulated by the H+-ATP synthase are of utmost interest to decipher the metabolic and redox circuits contributing to cancer origin and progression.
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Affiliation(s)
- Pau B Esparza-Moltó
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre (i+12), Universidad Autónoma de Madrid, Madrid, Spain
| | - José M Cuezva
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre (i+12), Universidad Autónoma de Madrid, Madrid, Spain
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61
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Transitional correlation between inner-membrane potential and ATP levels of neuronal mitochondria. Sci Rep 2018; 8:2993. [PMID: 29445117 PMCID: PMC5813116 DOI: 10.1038/s41598-018-21109-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/30/2018] [Indexed: 12/11/2022] Open
Abstract
The importance of highly active mitochondria and their contribution to neuronal function has been of recent interest. In most cases, however, mitochondrial activity is estimated using measurements of mitochondrial inner membrane potential (IMPmito), and little is known about the dynamics of native mitochondrial ATP (ATPmito). This study conducted simultaneous imaging of IMPmito and ATPmito in neurons to explore their behaviour and their correlation during physiological mitochondrial/neuronal activity. We found that mitochondrial size, transport velocity and transport direction are not dependent on ATPmito or IMPmito. However, changes in ATPmito and IMPmito during mitochondrial fission/fusion were found; IMPmito depolarized via mitochondrial fission and hyperpolarized via fusion, and ATPmito levels increased after fusion. Because the density of mitochondria is higher in growth cones (GCs) than in axonal processes, integrated ATPmito signals (density × ATPmito) were higher in GCs. This integrated signal in GCs correlated with axonal elongation. However, while the averaged IMPmito was relatively hyperpolarized in GCs, there was no correlation between IMPmito in GCs and axonal elongation. A detailed time-course analysis performed to clarify the reason for these discrepancies showed that IMPmito and ATPmito levels did not always correlate accurately; rather, there were several correlation patterns that changed over time.
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62
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ATP synthase from Trypanosoma brucei has an elaborated canonical F 1-domain and conventional catalytic sites. Proc Natl Acad Sci U S A 2018; 115:2102-2107. [PMID: 29440423 DOI: 10.1073/pnas.1720940115] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The structures and functions of the components of ATP synthases, especially those subunits involved directly in the catalytic formation of ATP, are widely conserved in metazoans, fungi, eubacteria, and plant chloroplasts. On the basis of a map at 32.5-Å resolution determined in situ in the mitochondria of Trypanosoma brucei by electron cryotomography, it has been proposed that the ATP synthase in this species has a noncanonical structure and different catalytic sites in which the catalytically essential arginine finger is provided not by the α-subunit adjacent to the catalytic nucleotide-binding site as in all species investigated to date, but rather by a protein, p18, found only in the euglenozoa. A crystal structure at 3.2-Å resolution of the catalytic domain of the same enzyme demonstrates that this proposal is incorrect. In many respects, the structure is similar to the structures of F1-ATPases determined previously. The α3β3-spherical portion of the catalytic domain in which the three catalytic sites are found, plus the central stalk, are highly conserved, and the arginine finger is provided conventionally by the α-subunits adjacent to each of the three catalytic sites found in the β-subunits. Thus, the enzyme has a conventional catalytic mechanism. The structure differs from previous described structures by the presence of a p18 subunit, identified only in the euglenozoa, associated with the external surface of each of the three α-subunits, thereby elaborating the F1-domain. Subunit p18 is a pentatricopeptide repeat (PPR) protein with three PPRs and appears to have no function in the catalytic mechanism of the enzyme.
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63
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Structure and dynamics of rotary V 1 motor. Cell Mol Life Sci 2018; 75:1789-1802. [PMID: 29387903 PMCID: PMC5910484 DOI: 10.1007/s00018-018-2758-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/25/2017] [Accepted: 01/18/2018] [Indexed: 12/14/2022]
Abstract
Rotary ATPases are unique rotary molecular motors that function as energy conversion machines. Among all known rotary ATPases, F1-ATPase is the best characterized rotary molecular motor. There are many high-resolution crystal structures and the rotation dynamics have been investigated in detail by extensive single-molecule studies. In contrast, knowledge on the structure and rotation dynamics of V1-ATPase, another rotary ATPase, has been limited. However, recent high-resolution structural studies and single-molecule studies on V1-ATPase have provided new insights on how the catalytic sites in this molecular motor change its conformation during rotation driven by ATP hydrolysis. In this review, we summarize recent information on the structural features and rotary dynamics of V1-ATPase revealed from structural and single-molecule approaches and discuss the possible chemomechanical coupling scheme of V1-ATPase with a focus on differences between rotary molecular motors.
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64
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Varghese F, Blaza JN, Jones AJY, Jarman OD, Hirst J. Deleting the IF 1-like ζ subunit from Paracoccus denitrificans ATP synthase is not sufficient to activate ATP hydrolysis. Open Biol 2018; 8:170206. [PMID: 29367351 PMCID: PMC5795051 DOI: 10.1098/rsob.170206] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/26/2017] [Indexed: 11/12/2022] Open
Abstract
In oxidative phosphorylation, ATP synthases interconvert two forms of free energy: they are driven by the proton-motive force across an energy-transducing membrane to synthesize ATP and displace the ADP/ATP ratio from equilibrium. For thermodynamically efficient energy conversion they must be reversible catalysts. However, in many species ATP synthases are unidirectional catalysts (their rates of ATP hydrolysis are negligible), and in others mechanisms have evolved to regulate or minimize hydrolysis. Unidirectional catalysis by Paracoccus denitrificans ATP synthase has been attributed to its unique ζ subunit, which is structurally analogous to the mammalian inhibitor protein IF1 Here, we used homologous recombination to delete the ζ subunit from the P. denitrificans genome, and compared ATP synthesis and hydrolysis by the wild-type and knockout enzymes in inverted membrane vesicles and the F1-ATPase subcomplex. ATP synthesis was not affected by loss of the ζ subunit, and the rate of ATP hydrolysis increased by less than twofold, remaining negligible in comparison with the rates of the Escherichia coli and mammalian enzymes. Therefore, deleting the P. denitrificans ζ subunit is not sufficient to activate ATP hydrolysis. We close by considering our conclusions in the light of reversible catalysis and regulation in ATP synthase enzymes.
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Affiliation(s)
- Febin Varghese
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - James N Blaza
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Andrew J Y Jones
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Owen D Jarman
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
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65
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Formentini L, Ryan AJ, Gálvez-Santisteban M, Carter L, Taub P, Lapek JD, Gonzalez DJ, Villarreal F, Ciaraldi TP, Cuezva JM, Henry RR. Mitochondrial H +-ATP synthase in human skeletal muscle: contribution to dyslipidaemia and insulin resistance. Diabetologia 2017; 60:2052-2065. [PMID: 28770317 PMCID: PMC6572787 DOI: 10.1007/s00125-017-4379-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/25/2017] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS Mitochondria are important regulators of the metabolic phenotype in type 2 diabetes. A key factor in mitochondrial physiology is the H+-ATP synthase. The expression and activity of its physiological inhibitor, ATPase inhibitory factor 1 (IF1), controls tissue homeostasis, metabolic reprogramming and signalling. We aimed to characterise the putative role of IF1 in mediating skeletal muscle metabolism in obesity and diabetes. METHODS We examined the 'mitochondrial signature' of obesity and type 2 diabetes in a cohort of 100 metabolically characterised human skeletal muscle biopsy samples. The expression and activity of H+-ATP synthase, IF1 and key mitochondrial proteins were characterised, including their association with BMI, fasting plasma insulin, fasting plasma glucose and HOMA-IR. IF1 was also overexpressed in primary cultures of human myotubes derived from the same biopsies to unveil the possible role played by the pathological inhibition of the H+-ATP synthase in skeletal muscle. RESULTS The results indicate that type 2 diabetes and obesity act via different mechanisms to impair H+-ATP synthase activity in human skeletal muscle (76% reduction in its catalytic subunit vs 280% increase in IF1 expression, respectively) and unveil a new pathway by which IF1 influences lipid metabolism. Mechanistically, IF1 altered cellular levels of α-ketoglutarate and L-carnitine metabolism in the myotubes of obese (84% of control) and diabetic (76% of control) individuals, leading to limited β-oxidation of fatty acids (60% of control) and their cytosolic accumulation (164% of control). These events led to enhanced release of TNF-α (10 ± 2 pg/ml, 27 ± 5 pg/ml and 35 ± 4 pg/ml in control, obese and type 2 diabetic participants, respectively), which probably contributes to an insulin resistant phenotype. CONCLUSIONS/INTERPRETATION Overall, our data highlight IF1 as a novel regulator of lipid metabolism and metabolic disorders, and a possible target for therapeutic intervention.
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Affiliation(s)
- Laura Formentini
- VA San Diego Healthcare System, San Diego, CA, USA.
- Departamento de Biología Molecular, CIBER Enfermedades Raras, Centro de Biología Molecular 'Severo Ochoa' (CBMSO), c/ Nicolás Cabrera 1, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
| | - Alexander J Ryan
- VA San Diego Healthcare System, San Diego, CA, USA
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | | | | | - Pam Taub
- VA San Diego Healthcare System, San Diego, CA, USA
- Department of Cardiology, University of California, San Diego, La Jolla, CA, USA
| | - John D Lapek
- Department of Pharmacology and Pharmacy, University of California, San Diego, La Jolla, CA, USA
| | - David J Gonzalez
- Department of Pharmacology and Pharmacy, University of California, San Diego, La Jolla, CA, USA
| | | | - Theodore P Ciaraldi
- VA San Diego Healthcare System, San Diego, CA, USA
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - José M Cuezva
- Departamento de Biología Molecular, CIBER Enfermedades Raras, Centro de Biología Molecular 'Severo Ochoa' (CBMSO), c/ Nicolás Cabrera 1, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Robert R Henry
- VA San Diego Healthcare System, San Diego, CA, USA
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA
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66
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Yang K, Long Q, Saja K, Huang F, Pogwizd SM, Zhou L, Yoshida M, Yang Q. Knockout of the ATPase inhibitory factor 1 protects the heart from pressure overload-induced cardiac hypertrophy. Sci Rep 2017; 7:10501. [PMID: 28874825 PMCID: PMC5585346 DOI: 10.1038/s41598-017-11251-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 08/15/2017] [Indexed: 12/15/2022] Open
Abstract
Mitochondrial ATP synthase catalyzes the coupling of oxidative phosphorylation. Under pathological conditions, ATP synthase hydrolyzes ATP to replenish protons from the matrix into the intermembrane space, sustaining mitochondrial membrane potential. ATPase inhibitory factor 1 (IF1) is a nuclear-encoded, ATP synthase-interacting protein that selectively inhibits the hydrolysis activity of ATP synthase, which may render the protective role of IF1 in ischemic hearts. However, the in vivo cardiac function of IF1 and the potential therapeutic application targeting IF1 remain obscure. In the present study, we uncovered that IF1 is upregulated in mouse hearts with pressure overload-induced hypertrophy and in human hearts with dilated cardiomyopathy. IF1 knockout (KO) mice were protected against cardiac dysfunction and pathological development induced by transverse aortic constriction (TAC) or isoproterenol infusion. The reduced ATP hydrolysis activated AMPK activity in IF1 KO hearts, which together facilitated autophagy. These results suggest that IF1 upregulation in the failing heart may be a maladaptive response. Inhibiting IF1 in the hypertrophied heart not only prevents cell death from excessive mitochondrial depolarization but also activates AMPK signaling and increases autophagy. Therefore, IF1 inhibition may serve as a potential therapeutic target in treating pathological cardiac hypertrophy and heart failure.
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Affiliation(s)
- Kevin Yang
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Qinqiang Long
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
- Departments of Internal Medicine and Institute of Hypertension, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China
| | - Kamalamma Saja
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
- Department of Biochemistry, University of Kerala, Thiruvananthapuram, Kerala, 695 581, India
| | - Fengyuan Huang
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Steven M Pogwizd
- Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Lufang Zhou
- Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA
| | - Masasuke Yoshida
- Department of Molecular Bioscience, Kyoto Sangyo University, Kamigamo-Motoyama, Kyoto, 603-8555, Japan
| | - Qinglin Yang
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, Alabama, 35294, USA.
- Departments of Internal Medicine and Institute of Hypertension, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P. R. China.
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67
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He J, Carroll J, Ding S, Fearnley IM, Walker JE. Permeability transition in human mitochondria persists in the absence of peripheral stalk subunits of ATP synthase. Proc Natl Acad Sci U S A 2017; 114:9086-9091. [PMID: 28784775 PMCID: PMC5576841 DOI: 10.1073/pnas.1711201114] [Citation(s) in RCA: 145] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The opening of a nonspecific channel, known as the permeability transition pore (PTP), in the inner membranes of mitochondria can be triggered by calcium ions, leading to swelling of the organelle, disruption of the inner membrane and ATP synthesis, and cell death. Pore opening can be inhibited by cyclosporin A mediated via cyclophilin D. It has been proposed that the pore is associated with the dimeric ATP synthase and the oligomycin sensitivity conferral protein (OSCP), a component of the enzyme's peripheral stalk, provides the site at which cyclophilin D interacts. Subunit b contributes a central α-helical structure to the peripheral stalk, extending from near the top of the enzyme's catalytic domain and crossing the membrane domain of the enzyme via two α-helices. We investigated the possible involvement of the subunit b and the OSCP in the PTP by generating clonal cells, HAP1-Δb and HAP1-ΔOSCP, lacking the membrane domain of subunit b or the OSCP, respectively, in which the corresponding genes, ATP5F1 and ATP5O, had been disrupted. Both cell lines preserve the characteristic properties of the PTP; therefore, the membrane domain of subunit b does not contribute to the PTP, and the OSCP does not provide the site of interaction with cyclophilin D. The membrane subunits ATP6, ATP8, and subunit c have been eliminated previously from possible participation in the PTP; thus, the only subunits of ATP synthase that could participate in pore formation are e, f, g, diabetes-associated protein in insulin-sensitive tissues (DAPIT), and the 6.8-kDa proteolipid.
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Affiliation(s)
- Jiuya He
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Joe Carroll
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Shujing Ding
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Ian M Fearnley
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - John E Walker
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, United Kingdom
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68
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Nesci S, Trombetti F, Ventrella V, Pagliarani A. Post-translational modifications of the mitochondrial F 1F O-ATPase. Biochim Biophys Acta Gen Subj 2017; 1861:2902-2912. [PMID: 28782624 DOI: 10.1016/j.bbagen.2017.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 07/27/2017] [Accepted: 08/03/2017] [Indexed: 12/16/2022]
Abstract
BACKGROUND The mitochondrial F1FO-ATPase has the main role in synthesizing most of ATP, thus providing energy to living cells, but it also works in reverse and hydrolyzes ATP, depending on the transmembrane electrochemical gradient. Within the same complex the vital role of the enzyme of life coexists with that of molecular switch to trigger programmed cell death. The two-faced vital/lethal role makes the enzyme complex an intriguing biochemical target to fight pathogens resistant to traditional therapies and diseases linked to mitochondrial dysfunctions. A variety of post-translational modifications (PTMs) of selected F1FO-ATPase aminoacids have been reported to affect the enzyme function. SCOPE OF REVIEW By reviewing the known PTMs of aminoacid side chains of both F1 and FO sectors according to the most recent advances, the main aim is to highlight how local chemical changes may constitute the molecular key leading to pathological or physiological events. MAJOR CONCLUSIONS PTMs represent the chemical tool to modulate the F1FO-ATPase activity in response to different stimuli. Some PTMs are required to ensure the enzyme catalysis or, conversely, to inactivate the enzyme function. Each covalent modification of the F1FO-ATPase, which occur in response to local changes, is the result of a selective molecular mechanism which, by translating a chemical modification into a biochemical effect, guarantees the enzyme tuning under changing conditions. GENERAL SIGNIFICANCE Once highlighted how the molecular mechanism works, some PTMs may be exploited to modulate the effect of drugs targeting the enzyme complex or constitute promising tools for F1FO-ATPase-targeted therapeutic strategies.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, via Tolara di Sopra 50, 40064 Ozzano dell'Emilia, BO, Italy
| | - Fabiana Trombetti
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, via Tolara di Sopra 50, 40064 Ozzano dell'Emilia, BO, Italy
| | - Vittoria Ventrella
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, via Tolara di Sopra 50, 40064 Ozzano dell'Emilia, BO, Italy
| | - Alessandra Pagliarani
- Department of Veterinary Medical Sciences (DIMEVET), University of Bologna, via Tolara di Sopra 50, 40064 Ozzano dell'Emilia, BO, Italy.
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69
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Wang Y, Hou Q, Xiao G, Yang S, Di C, Si J, Zhou R, Ye Y, Zhang Y, Zhang H. Selective ATP hydrolysis inhibition in F1Fo ATP synthase enhances radiosensitivity in non-small-cell lung cancer cells (A549). Oncotarget 2017; 8:53602-53612. [PMID: 28881834 PMCID: PMC5581133 DOI: 10.18632/oncotarget.18657] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/23/2017] [Indexed: 12/26/2022] Open
Abstract
Background F1Fo-ATP synthase (F1Fo-ATPase) is a reversibly rotary molecular machine whose dual functions of synthesizing or hydrolyzing ATP switch upon the condition of cell physiology. The robust ATP-hydrolyzing activity occurs in ischemia for maintaining the transmembrane proton motive force of mitochondria inner membrane, but the effect of F1Fo-ATPase on X-ray response of non-small-cell lung cancer (NSCLC) cells is unknown. Methods and Findings We studied whether ATP hydrolysis affected X-ray radiation induced cell death. NSCLC cells (A549) were pretreated with BTB06584 (BTB), an elective ATP hydrolysis inhibitor, followed by X-ray radiation. Cell viability and clonogenic survival were markedly decreased, clear indications of enhanced radiosensitivity through BTB incubation. Additionally, ATP5α1 was upregulated in parallel with elevated ATP hydrolytic activity after X-ray radiation, showing an increased mitochondrial membrane potential (ΔΨm). ATP hydrolysis inhibition led to collapse of ΔΨm suggesting ATP hydrolytic activity could enhance ΔΨm after X-ray radiation. Furthermore, we also demonstrated that apoptosis was pronounced with the prolonged collapse of ΔΨm due to hydrolysis inhibition by BTB incubation. Conclusion Overall, these findings supported that ATP hydrolysis inhibition could enhance the radiosensitivity in NSCLC cells (A549) after X-ray radiation, which was due to the collapse of ΔΨm.
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Affiliation(s)
- Yupei Wang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China.,CAS Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Lanzhou 730000, Gansu, China.,Key Laboratory of Heavy Ion Radiation Medicine of Gansu Province, Institute of Modern Physics, Lanzhou 730000, Gansu, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qinzheng Hou
- College of Life Science, Northwest Normal University, Lanzhou 730070, Gansu, China
| | - Guoqing Xiao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China
| | - Shifeng Yang
- School of Pharmacy, Lanzhou University, Lanzhou 730000, Gansu, China
| | - Cuixia Di
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China.,CAS Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Lanzhou 730000, Gansu, China.,Key Laboratory of Heavy Ion Radiation Medicine of Gansu Province, Institute of Modern Physics, Lanzhou 730000, Gansu, China
| | - Jing Si
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China.,CAS Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Lanzhou 730000, Gansu, China.,Key Laboratory of Heavy Ion Radiation Medicine of Gansu Province, Institute of Modern Physics, Lanzhou 730000, Gansu, China
| | - Rong Zhou
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China.,CAS Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Lanzhou 730000, Gansu, China.,Key Laboratory of Heavy Ion Radiation Medicine of Gansu Province, Institute of Modern Physics, Lanzhou 730000, Gansu, China
| | - Yancheng Ye
- Gansu Wuwei Tumor Hospital, Department of Science and Technology, Wuwei 733000, Gansu, China
| | - Yanshan Zhang
- Gansu Wuwei Tumor Hospital, Department of Science and Technology, Wuwei 733000, Gansu, China
| | - Hong Zhang
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, Gansu, China.,CAS Key Laboratory of Heavy Ion Radiation Biology and Medicine, Institute of Modern Physics, Lanzhou 730000, Gansu, China.,Gansu Wuwei Tumor Hospital, Department of Science and Technology, Wuwei 733000, Gansu, China.,Key Laboratory of Heavy Ion Radiation Medicine of Gansu Province, Institute of Modern Physics, Lanzhou 730000, Gansu, China
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70
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Esparza-Moltó PB, Nuevo-Tapioles C, Cuezva JM. Regulation of the H +-ATP synthase by IF1: a role in mitohormesis. Cell Mol Life Sci 2017; 74:2151-2166. [PMID: 28168445 PMCID: PMC5425498 DOI: 10.1007/s00018-017-2462-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 01/09/2017] [Accepted: 01/10/2017] [Indexed: 01/18/2023]
Abstract
The mitochondrial H+-ATP synthase is a primary hub of cellular homeostasis by providing the energy required to sustain cellular activity and regulating the production of signaling molecules that reprogram nuclear activity needed for adaption to changing cues. Herein, we summarize findings regarding the regulation of the activity of the H+-ATP synthase by its physiological inhibitor, the ATPase inhibitory factor 1 (IF1) and their functional role in cellular homeostasis. First, we outline the structure and the main molecular mechanisms that regulate the activity of the enzyme. Next, we describe the molecular biology of IF1 and summarize the regulation of IF1 expression and activity as an inhibitor of the H+-ATP synthase emphasizing the role of IF1 as a main driver of energy rewiring and cellular signaling in cancer. Findings in transgenic mice in vivo indicate that the overexpression of IF1 is sufficient to reprogram energy metabolism to an enhanced glycolysis and activate reactive oxygen species (ROS)-dependent signaling pathways that promote cell survival. These findings are placed in the context of mitohormesis, a program in which a mild mitochondrial stress triggers adaptive cytoprotective mechanisms that improve lifespan. In this regard, we emphasize the role played by the H+-ATP synthase in modulating signaling pathways that activate the mitohormetic response, namely ATP, ROS and target of rapamycin (TOR). Overall, we aim to highlight the relevant role of the H+-ATP synthase and of IF1 in cellular physiology and the need of additional studies to decipher their contributions to aging and age-related diseases.
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Affiliation(s)
- Pau B Esparza-Moltó
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Cristina Nuevo-Tapioles
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - José M Cuezva
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
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71
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Formentini L, Santacatterina F, Núñez de Arenas C, Stamatakis K, López-Martínez D, Logan A, Fresno M, Smits R, Murphy MP, Cuezva JM. Mitochondrial ROS Production Protects the Intestine from Inflammation through Functional M2 Macrophage Polarization. Cell Rep 2017; 19:1202-1213. [DOI: 10.1016/j.celrep.2017.04.036] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 03/03/2017] [Accepted: 04/12/2017] [Indexed: 01/06/2023] Open
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72
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Trypanosoma brucei TbIF1 inhibits the essential F1-ATPase in the infectious form of the parasite. PLoS Negl Trop Dis 2017; 11:e0005552. [PMID: 28414727 PMCID: PMC5407850 DOI: 10.1371/journal.pntd.0005552] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 04/27/2017] [Accepted: 04/04/2017] [Indexed: 12/01/2022] Open
Abstract
The mitochondrial (mt) FoF1-ATP synthase of the digenetic parasite, Trypanosoma brucei, generates ATP during the insect procyclic form (PF), but becomes a perpetual consumer of ATP in the mammalian bloodstream form (BF), which lacks a canonical respiratory chain. This unconventional dependence on FoF1-ATPase is required to maintain the essential mt membrane potential (Δψm). Normally, ATP hydrolysis by this rotary molecular motor is restricted to when eukaryotic cells experience sporadic hypoxic conditions, during which this compulsory function quickly depletes the cellular ATP pool. To protect against this cellular treason, the highly conserved inhibitory factor 1 (IF1) binds the enzyme in a manner that solely inhibits the hydrolytic activity. Intriguingly, we were able to identify the IF1 homolog in T. brucei (TbIF1), but determined that its expression in the mitochondrion is tightly regulated throughout the life cycle as it is only detected in PF cells. TbIF1 appears to primarily function as an emergency brake in PF cells, where it prevented the restoration of the Δψm by FoF1-ATPase when respiration was chemically inhibited. In vitro, TbIF1 overexpression specifically inhibits the hydrolytic activity but not the synthetic capability of the FoF1-ATP synthase in PF mitochondria. Furthermore, low μM amounts of recombinant TbIF1 achieve the same inhibition of total mt ATPase activity as the FoF1-ATPase specific inhibitors, azide and oligomycin. Therefore, even minimal ectopic expression of TbIF1 in BF cells proved lethal as the indispensable Δψm collapsed due to inhibited FoF1-ATPase. In summary, we provide evidence that T. brucei harbors a natural and potent unidirectional inhibitor of the vital FoF1-ATPase activity that can be exploited for future structure-based drug design. Enzymes are catalysts that drive both a forward and reverse chemical reaction depending on the thermodynamic properties. FoF1-ATP synthase is a multiprotein enzyme that under normal physiological conditions generates ATP. However, when respiration is impeded, this rotary molecular machine reverses and hydrolyzes ATP to pump protons and maintain the essential mitochondrial membrane potential. While this activity is exceptional in most eukaryotic cells, the unique composition of the Trypanosoma brucei mitochondrion dictates that the infectious stage of this human parasite is utterly dependent on the hydrolytic activity of FoF1-ATPase. While searching for better chemotherapeutics against Human African Trypanosomiasis, several trypanocidal compounds were determined to interact with this enzyme, but they indiscriminately inhibit both the ATP hydrolytic and synthetic activities. A more promising approach involves the conserved eukaryotic protein IF1, a unidirectional inhibitor that prevents just ATP hydrolysis. Auspiciously, we identified this protein homolog in T. brucei (TbIF1) and its expression is tightly regulated between life stages of the parasite. Importantly, the introduction of exogenous TbIF1 protein specifically inhibits FoF1-ATPase and is lethal for the infectious stage of T. brucei. Therefore, we have identified a natural inhibitor of an essential and druggable enzyme that can be exploited for future structure-based drug design.
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73
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García-Ledo L, Nuevo-Tapioles C, Cuevas-Martín C, Martínez-Reyes I, Soldevilla B, González-Llorente L, Cuezva JM. Overexpression of the ATPase Inhibitory Factor 1 Favors a Non-metastatic Phenotype in Breast Cancer. Front Oncol 2017; 7:69. [PMID: 28443245 PMCID: PMC5385467 DOI: 10.3389/fonc.2017.00069] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/27/2017] [Indexed: 01/03/2023] Open
Abstract
Partial suppression of mitochondrial oxidative phosphorylation and the concurrent activation of aerobic glycolysis is a hallmark of proliferating cancer cells. Overexpression of the ATPase inhibitory factor 1 (IF1), an in vivo inhibitor of the mitochondrial ATP synthase, is observed in most prevalent human carcinomas favoring metabolic rewiring to an enhanced glycolysis and cancer progression. Consistently, a high expression of IF1 in hepatocarcinomas and in carcinomas of the lung, bladder, and stomach and in gliomas is a biomarker of bad patient prognosis. In contrast to these findings, we have previously reported that a high expression level of IF1 in breast carcinomas is indicative of less chance to develop metastatic disease. This finding is especially relevant in the bad prognosis group of patients bearing triple-negative breast carcinomas. To investigate the molecular mechanisms that underlie the differential behavior of IF1 in breast cancer progression, we have developed the triple-negative BT549 breast cancer cell line that overexpresses IF1 stably. When compared to controls, IF1-cells partially shut down respiration and enhance aerobic glycolysis. Transcriptomic analysis suggested that migration and invasion were specifically inhibited in IF1-overexpressing breast cancer cells. Analysis of gene expression by qPCR and western blotting indicate that IF1 overexpression supports the maintenance of components of the extracellular matrix (ECM) and E-cadherin concurrently with the downregulation of components and signaling pathways involved in epithelial to mesenchymal transition. The overexpression of IF1 in breast cancer cells has no effect in the rates of cellular proliferation and in the cell death response to staurosporine and hydrogen peroxide. However, the overexpression of IF1 significantly diminishes the ability of the cells to grow in soft agar and to migrate and invade when compared to control cells. Overall, the results indicate that IF1 overexpression despite favoring a metabolic phenotype prone to cancer progression in the specific case of breast cancer cells also promotes the maintenance of the ECM impeding metastatic disease. These findings hence provide a mechanistic explanation to the better prognosis of breast cancer patients bearing tumors with high expression level of IF1.
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Affiliation(s)
- Lucía García-Ledo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, Madrid, Spain
| | - Cristina Nuevo-Tapioles
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, Madrid, Spain
| | - Carmen Cuevas-Martín
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, Madrid, Spain
| | - Inmaculada Martínez-Reyes
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, Madrid, Spain
| | - Beatriz Soldevilla
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lucía González-Llorente
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, Madrid, Spain
| | - José M Cuezva
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, Madrid, Spain
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74
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Persistence of the mitochondrial permeability transition in the absence of subunit c of human ATP synthase. Proc Natl Acad Sci U S A 2017; 114:3409-3414. [PMID: 28289229 DOI: 10.1073/pnas.1702357114] [Citation(s) in RCA: 190] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The permeability transition in human mitochondria refers to the opening of a nonspecific channel, known as the permeability transition pore (PTP), in the inner membrane. Opening can be triggered by calcium ions, leading to swelling of the organelle, disruption of the inner membrane, and ATP synthesis, followed by cell death. Recent proposals suggest that the pore is associated with the ATP synthase complex and specifically with the ring of c-subunits that constitute the membrane domain of the enzyme's rotor. The c-subunit is produced from three nuclear genes, ATP5G1, ATP5G2, and ATP5G3, encoding identical copies of the mature protein with different mitochondrial-targeting sequences that are removed during their import into the organelle. To investigate the involvement of the c-subunit in the PTP, we generated a clonal cell, HAP1-A12, from near-haploid human cells, in which ATP5G1, ATP5G2, and ATP5G3 were disrupted. The HAP1-A12 cells are incapable of producing the c-subunit, but they preserve the characteristic properties of the PTP. Therefore, the c-subunit does not provide the PTP. The mitochondria in HAP1-A12 cells assemble a vestigial ATP synthase, with intact F1-catalytic and peripheral stalk domains and the supernumerary subunits e, f, and g, but lacking membrane subunits ATP6 and ATP8. The same vestigial complex plus associated c-subunits was characterized from human 143B ρ0 cells, which cannot make the subunits ATP6 and ATP8, but retain the PTP. Therefore, none of the membrane subunits of the ATP synthase that are involved directly in transmembrane proton translocation is involved in forming the PTP.
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75
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Suzuki K, Mizutani K, Maruyama S, Shimono K, Imai FL, Muneyuki E, Kakinuma Y, Ishizuka-Katsura Y, Shirouzu M, Yokoyama S, Yamato I, Murata T. Crystal structures of the ATP-binding and ADP-release dwells of the V 1 rotary motor. Nat Commun 2016; 7:13235. [PMID: 27807367 PMCID: PMC5095293 DOI: 10.1038/ncomms13235] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 09/14/2016] [Indexed: 12/21/2022] Open
Abstract
V1-ATPases are highly conserved ATP-driven rotary molecular motors found in various membrane systems. We recently reported the crystal structures for the Enterococcus hirae A3B3DF (V1) complex, corresponding to the catalytic dwell state waiting for ATP hydrolysis. Here we present the crystal structures for two other dwell states obtained by soaking nucleotide-free V1 crystals in ADP. In the presence of 20 μM ADP, two ADP molecules bind to two of three binding sites and cooperatively induce conformational changes of the third site to an ATP-binding mode, corresponding to the ATP-binding dwell. In the presence of 2 mM ADP, all nucleotide-binding sites are occupied by ADP to induce conformational changes corresponding to the ADP-release dwell. Based on these and previous findings, we propose a V1-ATPase rotational mechanism model.
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Affiliation(s)
- Kano Suzuki
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
| | - Kenji Mizutani
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
- Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
- Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan
| | - Shintaro Maruyama
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
| | - Kazumi Shimono
- Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi 274-8510, Japan
| | - Fabiana L. Imai
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
| | - Eiro Muneyuki
- Department of Physics, Faculty of Science and Engineering, Chuo University, 1-13-27 Kasuga, Tokyo 112-8551, Japan
| | - Yoshimi Kakinuma
- Laboratory of Molecular Physiology and Genetics, Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan
| | - Yoshiko Ishizuka-Katsura
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Mikako Shirouzu
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Shigeyuki Yokoyama
- RIKEN Structural Biology Laboratory, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
| | - Ichiro Yamato
- Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba 278-8510, Japan
| | - Takeshi Murata
- Department of Chemistry, Graduate School of Science, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
- Molecular Chirality Research Center, Chiba University, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
- Division of Structural and Synthetic Biology, RIKEN Center for Life Science Technologies, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan
- JST, PRESTO, 1-33 Yayoi-cho, Inage, Chiba 263-8522, Japan
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Structure of the mitochondrial ATP synthase from Pichia angusta determined by electron cryo-microscopy. Proc Natl Acad Sci U S A 2016; 113:12709-12714. [PMID: 27791192 DOI: 10.1073/pnas.1615902113] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The structure of the intact monomeric ATP synthase from the fungus, Pichia angusta, has been solved by electron cryo-microscopy. The structure provides insights into the mechanical coupling of the transmembrane proton motive force across mitochondrial membranes in the synthesis of ATP. This mechanism requires a strong and integral stator, consisting of the catalytic α3β3-domain, peripheral stalk, and, in the membrane domain, subunit a and associated supernumerary subunits, kept in contact with the rotor turning at speeds up to 350 Hz. The stator's integrity is ensured by robust attachment of both the oligomycin sensitivity conferral protein (OSCP) to the catalytic domain and the membrane domain of subunit b to subunit a. The ATP8 subunit provides an additional brace between the peripheral stalk and subunit a. At the junction between the OSCP and the apparently stiff, elongated α-helical b-subunit and associated d- and h-subunits, an elbow or joint allows the stator to bend to accommodate lateral movements during the activity of the catalytic domain. The stator may also apply lateral force to help keep the static a-subunit and rotating c10-ring together. The interface between the c10-ring and the a-subunit contains the transmembrane pathway for protons, and their passage across the membrane generates the turning of the rotor. The pathway has two half-channels containing conserved polar residues provided by a bundle of four α-helices inclined at ∼30° to the plane of the membrane, similar to those described in other species. The structure provides more insights into the workings of this amazing machine.
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77
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Regulation of the thermoalkaliphilic F1-ATPase from Caldalkalibacillus thermarum. Proc Natl Acad Sci U S A 2016; 113:10860-5. [PMID: 27621435 DOI: 10.1073/pnas.1612035113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The crystal structure has been determined of the F1-catalytic domain of the F-ATPase from Caldalkalibacillus thermarum, which hydrolyzes adenosine triphosphate (ATP) poorly. It is very similar to those of active mitochondrial and bacterial F1-ATPases. In the F-ATPase from Geobacillus stearothermophilus, conformational changes in the ε-subunit are influenced by intracellular ATP concentration and membrane potential. When ATP is plentiful, the ε-subunit assumes a "down" state, with an ATP molecule bound to its two C-terminal α-helices; when ATP is scarce, the α-helices are proposed to inhibit ATP hydrolysis by assuming an "up" state, where the α-helices, devoid of ATP, enter the α3β3-catalytic region. However, in the Escherichia coli enzyme, there is no evidence that such ATP binding to the ε-subunit is mechanistically important for modulating the enzyme's hydrolytic activity. In the structure of the F1-ATPase from C. thermarum, ATP and a magnesium ion are bound to the α-helices in the down state. In a form with a mutated ε-subunit unable to bind ATP, the enzyme remains inactive and the ε-subunit is down. Therefore, neither the γ-subunit nor the regulatory ATP bound to the ε-subunit is involved in the inhibitory mechanism of this particular enzyme. The structure of the α3β3-catalytic domain is likewise closely similar to those of active F1-ATPases. However, although the βE-catalytic site is in the usual "open" conformation, it is occupied by the unique combination of an ADP molecule with no magnesium ion and a phosphate ion. These bound hydrolytic products are likely to be the basis of inhibition of ATP hydrolysis.
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78
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Cardiolipin binds selectively but transiently to conserved lysine residues in the rotor of metazoan ATP synthases. Proc Natl Acad Sci U S A 2016; 113:8687-92. [PMID: 27382158 PMCID: PMC4978264 DOI: 10.1073/pnas.1608396113] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The anionic lipid cardiolipin is an essential component of active ATP synthases. In metazoans, their rotors contain a ring of eight c-subunits consisting of inner and outer circles of N- and C-terminal α-helices, respectively. The beginning of the C-terminal α-helix contains a strictly conserved and fully trimethylated lysine residue in the lipid head-group region of the membrane. Larger rings of known structure, from c9-c15 in eubacteria and chloroplasts, conserve either a lysine or an arginine residue in the equivalent position. In computer simulations of hydrated membranes containing trimethylated or unmethylated bovine c8-rings and bacterial c10- or c11-rings, the head-groups of cardiolipin molecules became associated selectively with these modified and unmodified lysine residues and with adjacent polar amino acids and with a second conserved lysine on the opposite side of the membrane, whereas phosphatidyl lipids were attracted little to these sites. However, the residence times of cardiolipin molecules with the ring were brief and sufficient for the rotor to turn only a fraction of a degree in the active enzyme. With the demethylated c8-ring and with c10- and c11-rings, the density of bound cardiolipin molecules at this site increased, but residence times were not changed greatly. These highly specific but brief interactions with the rotating c-ring are consistent with functional roles for cardiolipin in stabilizing and lubricating the rotor, and, by interacting with the enzyme at the inlet and exit of the transmembrane proton channel, in participation in proton translocation through the membrane domain of the enzyme.
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79
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García-Bermúdez J, Cuezva JM. The ATPase Inhibitory Factor 1 (IF1): A master regulator of energy metabolism and of cell survival. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1857:1167-1182. [PMID: 26876430 DOI: 10.1016/j.bbabio.2016.02.004] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 01/28/2016] [Accepted: 02/07/2016] [Indexed: 12/19/2022]
Abstract
In this contribution we summarize most of the findings reported for the molecular and cellular biology of the physiological inhibitor of the mitochondrial H(+)-ATP synthase, the engine of oxidative phosphorylation (OXPHOS) and gate of cell death. We first describe the structure and major mechanisms and molecules that regulate the activity of the ATP synthase placing the ATPase Inhibitory Factor 1 (IF1) as a major determinant in the regulation of the activity of the ATP synthase and hence of OXPHOS. Next, we summarize the post-transcriptional mechanisms that regulate the expression of IF1 and emphasize, in addition to the regulation afforded by the protonation state of histidine residues, that the activity of IF1 as an inhibitor of the ATP synthase is also regulated by phosphorylation of a serine residue. Phosphorylation of S39 in IF1 by the action of a mitochondrial cAMP-dependent protein kinase A hampers its interaction with the ATP synthase, i.e., only dephosphorylated IF1 interacts with the enzyme. Upon IF1 interaction with the ATP synthase both the synthetic and hydrolytic activities of the engine of OXPHOS are inhibited. These findings are further placed into the physiological context to stress the emerging roles played by IF1 in metabolic reprogramming in cancer, in hypoxia and in cellular differentiation. We review also the implication of IF1 in other cellular situations that involve the malfunctioning of mitochondria. Special emphasis is given to the role of IF1 as driver of the generation of a reactive oxygen species signal that, emanating from mitochondria, is able to reprogram the nucleus of the cell to confer by various signaling pathways a cell-death resistant phenotype against oxidative stress. Overall, our intention is to highlight the urgent need of further investigations in the molecular and cellular biology of IF1 and of its target, the ATP synthase, to unveil new therapeutic strategies in human pathology. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Javier García-Bermúdez
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - José M Cuezva
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
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80
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Hahn A, Parey K, Bublitz M, Mills DJ, Zickermann V, Vonck J, Kühlbrandt W, Meier T. Structure of a Complete ATP Synthase Dimer Reveals the Molecular Basis of Inner Mitochondrial Membrane Morphology. Mol Cell 2016; 63:445-56. [PMID: 27373333 PMCID: PMC4980432 DOI: 10.1016/j.molcel.2016.05.037] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 04/21/2016] [Accepted: 05/26/2016] [Indexed: 11/28/2022]
Abstract
We determined the structure of a complete, dimeric F1Fo-ATP synthase from yeast Yarrowia lipolytica mitochondria by a combination of cryo-EM and X-ray crystallography. The final structure resolves 58 of the 60 dimer subunits. Horizontal helices of subunit a in Fo wrap around the c-ring rotor, and a total of six vertical helices assigned to subunits a, b, f, i, and 8 span the membrane. Subunit 8 (A6L in human) is an evolutionary derivative of the bacterial b subunit. On the lumenal membrane surface, subunit f establishes direct contact between the two monomers. Comparison with a cryo-EM map of the F1Fo monomer identifies subunits e and g at the lateral dimer interface. They do not form dimer contacts but enable dimer formation by inducing a strong membrane curvature of ∼100°. Our structure explains the structural basis of cristae formation in mitochondria, a landmark signature of eukaryotic cell morphology. Cryo-EM structure of a yeast F1Fo-ATP synthase dimer Inhibitor-free X-ray structure of the F1 head and rotor complex Mechanism of ATP generation by rotary catalysis Structural basis of cristae formation in the inner mitochondrial membrane
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Affiliation(s)
- Alexander Hahn
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Kristian Parey
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Maike Bublitz
- Institute of Biochemistry, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Deryck J Mills
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Volker Zickermann
- Institute of Biochemistry II, Medical School, Goethe University Frankfurt, Max-von-Laue-Str. 9, 60438 Frankfurt am Main, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany.
| | - Thomas Meier
- Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Str. 3, 60438 Frankfurt am Main, Germany.
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81
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Podrabsky JE, Hand SC. Physiological strategies during animal diapause: lessons from brine shrimp and annual killifish. ACTA ACUST UNITED AC 2016; 218:1897-906. [PMID: 26085666 DOI: 10.1242/jeb.116194] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Diapause is a programmed state of developmental arrest that typically occurs as part of the natural developmental progression of organisms that inhabit seasonal environments. The brine shrimp Artemia franciscana and annual killifish Austrofundulus limnaeus share strikingly similar life histories that include embryonic diapause as a means to synchronize the growth and reproduction phases of their life history to favorable environmental conditions. In both species, respiration rate is severely depressed during diapause and thus alterations in mitochondrial physiology are a key component of the suite of characters associated with cessation of development. Here, we use these two species to illustrate the basic principles of metabolic depression at the physiological and biochemical levels. It is clear that these two species use divergent molecular mechanisms to achieve the same physiological and ecological outcomes. This pattern of convergent physiological strategies supports the importance of biochemical and physiological adaptations to cope with extreme environmental stress and suggests that inferring mechanism from transcriptomics or proteomics or metabolomics alone, without rigorous follow-up at the biochemical and physiological levels, could lead to erroneous conclusions.
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Affiliation(s)
- Jason E Podrabsky
- Department of Biology, Portland State University, P.O. Box 751, Portland, OR 97207-0751, USA
| | - Steven C Hand
- Department of Biological Sciences, Division of Cellular, Integrative and Comparative Biology, Louisiana State University, Baton Rouge, LA 70803, USA
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82
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Santamaría-Gómez J, Ochoa de Alda JAG, Olmedo-Verd E, Bru-Martínez R, Luque I. Sub-Cellular Localization and Complex Formation by Aminoacyl-tRNA Synthetases in Cyanobacteria: Evidence for Interaction of Membrane-Anchored ValRS with ATP Synthase. Front Microbiol 2016; 7:857. [PMID: 27375579 PMCID: PMC4893482 DOI: 10.3389/fmicb.2016.00857] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 05/23/2016] [Indexed: 01/09/2023] Open
Abstract
tRNAs are charged with cognate amino acids by aminoacyl-tRNA synthetases (aaRSs) and subsequently delivered to the ribosome to be used as substrates for gene translation. Whether aminoacyl-tRNAs are channeled to the ribosome by transit within translational complexes that avoid their diffusion in the cytoplasm is a matter of intense investigation in organisms of the three domains of life. In the cyanobacterium Anabaena sp. PCC 7120, the valyl-tRNA synthetase (ValRS) is anchored to thylakoid membranes by means of the CAAD domain. We have investigated whether in this organism ValRS could act as a hub for the nucleation of a translational complex by attracting other aaRSs to the membranes. Out of the 20 aaRSs, only ValRS was found to localize in thylakoid membranes whereas the other enzymes occupied the soluble portion of the cytoplasm. To investigate the basis for this asymmetric distribution of aaRSs, a global search for proteins interacting with the 20 aaRSs was conducted. The interaction between ValRS and the FoF1 ATP synthase complex here reported is of utmost interest and suggests a functional link between elements of the gene translation and energy production machineries.
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Affiliation(s)
- Javier Santamaría-Gómez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
| | | | - Elvira Olmedo-Verd
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
| | - Roque Bru-Martínez
- Department of Agrochemistry and Biochemistry, Faculty of Science, University of AlicanteAlicante, Spain
| | - Ignacio Luque
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de SevillaSeville, Spain
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83
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Hand SC, Denlinger DL, Podrabsky JE, Roy R. Mechanisms of animal diapause: recent developments from nematodes, crustaceans, insects, and fish. Am J Physiol Regul Integr Comp Physiol 2016; 310:R1193-211. [PMID: 27053646 PMCID: PMC4935499 DOI: 10.1152/ajpregu.00250.2015] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 03/11/2016] [Indexed: 01/22/2023]
Abstract
Life cycle delays are beneficial for opportunistic species encountering suboptimal environments. Many animals display a programmed arrest of development (diapause) at some stage(s) of their development, and the diapause state may or may not be associated with some degree of metabolic depression. In this review, we will evaluate current advancements in our understanding of the mechanisms responsible for the remarkable phenotype, as well as environmental cues that signal entry and termination of the state. The developmental stage at which diapause occurs dictates and constrains the mechanisms governing diapause. Considerable progress has been made in clarifying proximal mechanisms of metabolic arrest and the signaling pathways like insulin/Foxo that control gene expression patterns. Overlapping themes are also seen in mechanisms that control cell cycle arrest. Evidence is emerging for epigenetic contributions to diapause regulation via small RNAs in nematodes, crustaceans, insects, and fish. Knockdown of circadian clock genes in selected insect species supports the importance of clock genes in the photoperiodic response that cues diapause. A large suite of chaperone-like proteins, expressed during diapause, protects biological structures during long periods of energy-limited stasis. More information is needed to paint a complete picture of how environmental cues are coupled to the signal transduction that initiates the complex diapause phenotype, as well as molecular explanations for how the state is terminated. Excellent examples of molecular memory in post-dauer animals have been documented in Caenorhabditis elegans It is clear that a single suite of mechanisms does not regulate diapause across all species and developmental stages.
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Affiliation(s)
- Steven C Hand
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana;
| | - David L Denlinger
- Departments of Entomology and Evolution, Ecology and Organismal Biology, Ohio State University, Columbus, Ohio
| | - Jason E Podrabsky
- Department of Biology, Portland State University, Portland, Oregon; and
| | - Richard Roy
- Department of Biology, McGill University, Montréal, Québec, Canada
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84
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The Dual Function of Reactive Oxygen/Nitrogen Species in Bioenergetics and Cell Death: The Role of ATP Synthase. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2016; 2016:3869610. [PMID: 27034734 PMCID: PMC4806282 DOI: 10.1155/2016/3869610] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 02/15/2016] [Indexed: 01/11/2023]
Abstract
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) targeting mitochondria are major causative factors in disease pathogenesis. The mitochondrial permeability transition pore (PTP) is a mega-channel modulated by calcium and ROS/RNS modifications and it has been described to play a crucial role in many pathophysiological events since prolonged channel opening causes cell death. The recent identification that dimers of ATP synthase form the PTP and the fact that posttranslational modifications caused by ROS/RNS also affect cellular bioenergetics through the modulation of ATP synthase catalysis reveal a dual function of these modifications in the cells. Here, we describe mitochondria as a major site of production and as a target of ROS/RNS and discuss the pathophysiological conditions in which oxidative and nitrosative modifications modulate the catalytic and pore-forming activities of ATP synthase.
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85
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Nakanishi-Matsui M, Sekiya M, Futai M. ATP synthase from Escherichia coli : Mechanism of rotational catalysis, and inhibition with the ε subunit and phytopolyphenols. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:129-140. [DOI: 10.1016/j.bbabio.2015.11.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/19/2015] [Accepted: 11/13/2015] [Indexed: 10/22/2022]
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86
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García-Trejo JJ, Zarco-Zavala M, Mendoza-Hoffmann F, Hernández-Luna E, Ortega R, Mendoza-Hernández G. The Inhibitory Mechanism of the ζ Subunit of the F1FO-ATPase Nanomotor of Paracoccus denitrificans and Related α-Proteobacteria. J Biol Chem 2016; 291:538-46. [PMID: 26546676 PMCID: PMC4705375 DOI: 10.1074/jbc.m115.688143] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 11/02/2015] [Indexed: 01/08/2023] Open
Abstract
The ζ subunit is a novel inhibitor of the F1FO-ATPase of Paracoccus denitrificans and related α-proteobacteria. It is different from the bacterial (ϵ) and mitochondrial (IF1) inhibitors. The N terminus of ζ blocks rotation of the γ subunit of the F1-ATPase of P. denitrificans (Zarco-Zavala, M., Morales-Ríos, E., Mendoza-Hernández, G., Ramírez-Silva, L., Pérez-Hernández, G., and García-Trejo, J. J. (2014) FASEB J. 24, 599-608) by a hitherto unknown quaternary structure that was first modeled here by structural homology and protein docking. The F1-ATPase and F1-ζ models of P. denitrificans were supported by cross-linking, limited proteolysis, mass spectrometry, and functional data. The final models show that ζ enters into F1-ATPase at the open catalytic αE/βE interface, and two partial γ rotations lock the N terminus of ζ in an "inhibition-general core region," blocking further γ rotation, while the ζ globular domain anchors it to the closed αDP/βDP interface. Heterologous inhibition of the F1-ATPase of P. denitrificans by the mitochondrial IF1 supported both the modeled ζ binding site at the αDP/βDP/γ interface and the endosymbiotic α-proteobacterial origin of mitochondria. In summary, the ζ subunit blocks the intrinsic rotation of the nanomotor by inserting its N-terminal inhibitory domain at the same rotor/stator interface where the mitochondrial IF1 or the bacterial ϵ binds. The proposed pawl mechanism is coupled to the rotation of the central γ subunit working as a ratchet but with structural differences that make it a unique control mechanism of the nanomotor to favor the ATP synthase activity over the ATPase turnover in the α-proteobacteria.
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Affiliation(s)
| | | | | | | | - Raquel Ortega
- From the Departamento de Biología, Facultad de Química, and
| | - Guillermo Mendoza-Hernández
- the Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, D.F., CP 04510, México
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87
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Structure of ATP synthase from Paracoccus denitrificans determined by X-ray crystallography at 4.0 Å resolution. Proc Natl Acad Sci U S A 2015; 112:13231-6. [PMID: 26460036 PMCID: PMC4629361 DOI: 10.1073/pnas.1517542112] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The structure of the intact ATP synthase from the α-proteobacterium Paracoccus denitrificans, inhibited by its natural regulatory ζ-protein, has been solved by X-ray crystallography at 4.0 Å resolution. The ζ-protein is bound via its N-terminal α-helix in a catalytic interface in the F1 domain. The bacterial F1 domain is attached to the membrane domain by peripheral and central stalks. The δ-subunit component of the peripheral stalk binds to the N-terminal regions of two α-subunits. The stalk extends via two parallel long α-helices, one in each of the related b and b' subunits, down a noncatalytic interface of the F1 domain and interacts in an unspecified way with the a-subunit in the membrane domain. The a-subunit lies close to a ring of 12 c-subunits attached to the central stalk in the F1 domain, and, together, the central stalk and c-ring form the enzyme's rotor. Rotation is driven by the transmembrane proton-motive force, by a mechanism where protons pass through the interface between the a-subunit and c-ring via two half-channels in the a-subunit. These half-channels are probably located in a bundle of four α-helices in the a-subunit that are tilted at ∼30° to the plane of the membrane. Conserved polar residues in the two α-helices closest to the c-ring probably line the proton inlet path to an essential carboxyl group in the c-subunit in the proton uptake site and a proton exit path from the proton release site. The structure has provided deep insights into the workings of this extraordinary molecular machine.
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88
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Linking structural features from mitochondrial and bacterial F-type ATP synthases to their distinct mechanisms of ATPase inhibition. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 119:94-102. [DOI: 10.1016/j.pbiomolbio.2015.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 06/25/2015] [Accepted: 06/26/2015] [Indexed: 01/11/2023]
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89
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Chimeo C, Fernandez-Gimenez AV, Campanella M, Mendez-Romero O, Muhlia-Almazan A. The shrimp mitochondrial FoF1-ATPase inhibitory factor 1 (IF1). J Bioenerg Biomembr 2015; 47:383-93. [PMID: 26302886 DOI: 10.1007/s10863-015-9621-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 08/12/2015] [Indexed: 12/16/2022]
Abstract
The whiteleg shrimp species Litopenaeus vannamei is exposed to cyclic changes of the dissolved oxygen concentration of seawater and must neutralize the adverse effects of hypoxia by using ATP as energy source. In crustaceans, the mitochondrial FOF1-ATP synthase is pivotal to the homeostasis of ATP and function prevalently as a FOF1-ATPase. Hitherto, it is unknown whether these marine invertebrates are equipped with molecules able to control the FOF1-ATPase inhibiting the ATP consumption. In this study, we report two variants of the mitochondrial FOF1-ATPase Inhibitory Factor 1 (IF1) ubiquitously expressed across tissues of the Litopenaeus vannamei transcriptome: the IF1_Lv1 and the IF1_Lv2. The IF1_Lv1, with a full-length sequence of 550 bp, encodes a 104 aa long protein and its mRNA amounts are significantly affected by hypoxia and re-oxygenation. The IF1_Lv2, with a sequence of 654 bp, encodes instead for a protein of 85 aa. Both proteins share a 69 % homology and contain a conserved minimal inhibitory sequence (IATP domain) along with a G-rich region on their N-terminus typical of the invertebrate. In light of this characterization IF1 is here discussed as an adaptive mechanism evolved by this marine species to inhibit the FOF1-ATPase activity and avoid ATP dissipation to thrive in spite of the changes in oxygen tension.
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Affiliation(s)
- Cindy Chimeo
- Bioenergetics and Molecular Genetics Lab, Centro de Investigacion en Alimentacion y Desarrollo (CIAD) A. C., Carretera a Ejido La Victoria Km 0.6, PO Box 1735, 83000, Hermosillo, Sonora, Mexico
| | - Analia Veronica Fernandez-Gimenez
- Laboratorio Fisiologia de Organismos Acuaticos. Instituto de Investigaciones Marinas y Costeras, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Buenos Aires, Argentina
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, London, UK
- University College London Consortium for Mitochondrial Research, Royal College Street NW1 0TU, London, UK
| | - Ofelia Mendez-Romero
- Bioenergetics and Molecular Genetics Lab, Centro de Investigacion en Alimentacion y Desarrollo (CIAD) A. C., Carretera a Ejido La Victoria Km 0.6, PO Box 1735, 83000, Hermosillo, Sonora, Mexico
| | - Adriana Muhlia-Almazan
- Bioenergetics and Molecular Genetics Lab, Centro de Investigacion en Alimentacion y Desarrollo (CIAD) A. C., Carretera a Ejido La Victoria Km 0.6, PO Box 1735, 83000, Hermosillo, Sonora, Mexico.
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90
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Sun L, Nakamae N, Ichikawa N. The region from phenylalanine-28 to lysine-50 of a yeast mitochondrial ATPase inhibitor (IF1) forms an α-helix in solution. J Bioenerg Biomembr 2015; 47:457-65. [PMID: 26420258 DOI: 10.1007/s10863-015-9627-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 09/16/2015] [Indexed: 10/23/2022]
Abstract
A mitochondrial ATPase inhibitor, IF1, is a 63 amino acid residue protein that regulates the activity of ATP synthase (F(1)F(o)-ATPase). In the present study, we constructed mutant IF1 proteins with proline residues inserted into a wide range of their primary structures to determine the location and function of α-helix in the protein. A total of 11 yeast IF1 protein mutants were expressed and purified. Proline insertions in the region 28-50 reduced α-helical contents, indicating that the region formed a helix in solution. Oligomer formation of proline mutants at the C-terminal 38-60 region was markedly reduced, indicating that the region is required for oligomerization of the protein. Proline mutants at the N-terminal 18-39 region did not inhibit F(1)F(o)-ATPase, indicating that the region is required for ATPase inhibitory activity. Inhibition of a proline insertion mutant between residues 44 and 45 that lost a large portion of the α-helix was slower, although the maximal inhibition level of the mutant protein was comparable to that of wild-type IF1. The results suggest that the helix of yeast IF1 facilitates binding to F(1) by promoting initial interaction of the proteins.
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Affiliation(s)
- Li Sun
- Department of Food and Human Health Sciences, Graduate School of Human Life Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan
| | - Naomi Nakamae
- Department of Food and Human Health Sciences, Graduate School of Human Life Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan
| | - Naoki Ichikawa
- Department of Food and Human Health Sciences, Graduate School of Human Life Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka, 558-8585, Japan.
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91
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On the Mg2+ binding site of the ε subunit from bacterial F-type ATP synthases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:1101-12. [DOI: 10.1016/j.bbabio.2015.05.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Revised: 05/20/2015] [Accepted: 05/22/2015] [Indexed: 11/19/2022]
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92
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García-Bermúdez J, Sánchez-Aragó M, Soldevilla B, Del Arco A, Nuevo-Tapioles C, Cuezva JM. PKA Phosphorylates the ATPase Inhibitory Factor 1 and Inactivates Its Capacity to Bind and Inhibit the Mitochondrial H(+)-ATP Synthase. Cell Rep 2015; 12:2143-55. [PMID: 26387949 DOI: 10.1016/j.celrep.2015.08.052] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Revised: 07/28/2015] [Accepted: 08/17/2015] [Indexed: 12/16/2022] Open
Abstract
The mitochondrial H(+)-ATP synthase synthesizes most of cellular ATP requirements by oxidative phosphorylation (OXPHOS). The ATPase Inhibitory Factor 1 (IF1) is known to inhibit the hydrolase activity of the H(+)-ATP synthase in situations that compromise OXPHOS. Herein, we demonstrate that phosphorylation of S39 in IF1 by mitochondrial protein kinase A abolishes its capacity to bind the H(+)-ATP synthase. Only dephosphorylated IF1 binds and inhibits both the hydrolase and synthase activities of the enzyme. The phosphorylation status of IF1 regulates the flux of aerobic glycolysis and ATP production through OXPHOS in hypoxia and during the cell cycle. Dephosphorylated IF1 is present in human carcinomas. Remarkably, mouse heart contains a large fraction of dephosphorylated IF1 that becomes phosphorylated and inactivated upon in vivo β-adrenergic stimulation. Overall, we demonstrate the essential function of the phosphorylation of IF1 in regulating energy metabolism and speculate that dephosho-IF1 might play a role in signaling mitohormesis.
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Affiliation(s)
- Javier García-Bermúdez
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - María Sánchez-Aragó
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Beatriz Soldevilla
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Araceli Del Arco
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049 Madrid, Spain; Área de Bioquímica, Universidad de Castilla la Mancha, 45071 Toledo, Spain
| | - Cristina Nuevo-Tapioles
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - José M Cuezva
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Centro de Investigación Biomédica en Red de Enfermedades Raras CIBERER-ISCIII, Instituto de Investigación Hospital 12 de Octubre, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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93
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Shirakihara Y, Shiratori A, Tanikawa H, Nakasako M, Yoshida M, Suzuki T. Structure of a thermophilic F1-ATPase inhibited by an ε-subunit: deeper insight into the ε-inhibition mechanism. FEBS J 2015; 282:2895-913. [PMID: 26032434 DOI: 10.1111/febs.13329] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 05/19/2015] [Accepted: 05/26/2015] [Indexed: 11/28/2022]
Abstract
F1-ATPase (F1) is the catalytic sector in F(o)F1-ATP synthase that is responsible for ATP production in living cells. In catalysis, its three catalytic β-subunits undergo nucleotide occupancy-dependent and concerted open-close conformational changes that are accompanied by rotation of the γ-subunit. Bacterial and chloroplast F1 are inhibited by their own ε-subunit. In the ε-inhibited Escherichia coli F1 structure, the ε-subunit stabilizes the overall conformation (half-closed, closed, open) of the β-subunits by inserting its C-terminal helix into the α3β3 cavity. The structure of ε-inhibited thermophilic F1 is similar to that of E. coli F1, showing a similar conformation of the ε-subunit, but the thermophilic ε-subunit stabilizes another unique overall conformation (open, closed, open) of the β-subunits. The ε-C-terminal helix 2 and hook are conserved between the two structures in interactions with target residues and in their positions. Rest of the ε-C-terminal domains are in quite different conformations and positions, and have different modes of interaction with targets. This region is thought to serve ε-inhibition differently. For inhibition, the ε-subunit contacts the second catches of some of the β- and α-subunits, the N- and C-terminal helices, and some of the Rossmann fold segments. Those contacts, as a whole, lead to positioning of those β- and α- second catches in ε-inhibition-specific positions, and prevent rotation of the γ-subunit. Some of the structural features are observed even in IF1 inhibition in mitochondrial F1.
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Affiliation(s)
| | | | | | - Masayoshi Nakasako
- The Institute of Molecular and Cellular Biosciences, The University of Tokyo, Japan
| | - Masasuke Yoshida
- The Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, Japan.,ERATO, Japan Science and Technology Corporation (JST), Yokohama, Japan
| | - Toshiharu Suzuki
- The Chemical Resources Laboratory, Tokyo Institute of Technology, Yokohama, Japan.,ERATO, Japan Science and Technology Corporation (JST), Yokohama, Japan
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94
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Kurbasic E, Sjöström M, Krogh M, Folkesson E, Grabau D, Hansson K, Rydén L, Waldemarson S, James P, Niméus E. Changes in glycoprotein expression between primary breast tumour and synchronous lymph node metastases or asynchronous distant metastases. Clin Proteomics 2015; 12:13. [PMID: 25991917 PMCID: PMC4436114 DOI: 10.1186/s12014-015-9084-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 04/13/2015] [Indexed: 12/27/2022] Open
Abstract
Background Breast cancer is a very heterogeneous disease and some patients are cured by the surgical removal of the primary tumour whilst other patients suffer from metastasis and spreading of the disease, despite adjuvant therapy. A number of prognostic and treatment predictive factors have been identified such as tumour size, oestrogen (ER) and progesterone (PgR) receptor status, human epidermal growth factor receptor type 2 (HER2) status, histological grade, Ki67 and age. Lymph node involvement is also assessed during surgery to determine if the tumour has spread which requires dissection of the axilla and adjuvant treatment. The prognostic and treatment predictive factors assessing the nature of the tumour are all routinely based on the status of the primary tumour. Results We have analysed a unique tumour set of fourteen primary breast cancer tumours with matched synchronous axillary lymph node metastases and a set of nine primary tumours with, later developed, matched distant metastases from different sites in the body. We used a pairwise tumour analysis (from the same individual) since the difference between the same tumour-type in different patients was greater. Glycopeptide capture was used in this study to selectively isolate and quantify N-linked glycopeptides from tumours mixtures and the captured glycopeptides were subjected to label-free quantitative tandem mass spectrometry analysis. Differentially expressed proteins between primary tumours and matched lymph node metastasis and distant metastasis were identified. Two of the top hits, ATPIF1 and tubulin β-chain were validated by immunohistochemistry to be differentially regulated. Conclusions We show that the expression of a large number of glycosylated proteins change between primary tumours and matched lymph node metastases and distant metastases, confirming that cancer cells undergo a molecular transformation during the spread to a secondary site. The proteins are part of important pathways such as cell adhesion, migration pathways and immune response giving insight into molecular changes needed for the tumour to spread. The large difference between primary tumours and lymph node and distant metastases also suggest that treatment should be based on the phenotype of the lymph node and distant metastases. Electronic supplementary material The online version of this article (doi:10.1186/s12014-015-9084-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Emila Kurbasic
- Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden
| | - Martin Sjöström
- Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden
| | - Morten Krogh
- Amber Biosciences AB, Skrivarevägen 9, SE-22657 Lund, Sweden
| | - Elin Folkesson
- Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden
| | - Dorthe Grabau
- Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden ; Department of Pathology, Skåne University Hospital, SE-22185 Lund, Sweden
| | - Karin Hansson
- Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden
| | - Lisa Rydén
- Department of Surgery, Clinical sciences, Lund University, SE-22185 Lund, Sweden ; Department of Surgery, Skåne University Hospital, SE-22185 Lund, Sweden
| | - Sofia Waldemarson
- Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden
| | - Peter James
- Department of Immunotechnology, House 406, Medicon Village, SE-223 81 Lund, Sweden
| | - Emma Niméus
- Division of Oncology and Pathology, Department of Clinical Sciences Lund, Lund University, Medicon Village, SE-223 81 Lund, Sweden ; Department of Surgery, Skåne University Hospital, SE-22185 Lund, Sweden
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95
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How release of phosphate from mammalian F1-ATPase generates a rotary substep. Proc Natl Acad Sci U S A 2015; 112:6009-14. [PMID: 25918412 PMCID: PMC4434703 DOI: 10.1073/pnas.1506465112] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
ATP, the fuel of life, is produced in the mitochondria of living cells by a molecular machine consisting of two motors linked by a rotor. One motor generates rotation by consuming energy derived from sugars and fats in foodstuffs; the other uses energy transmitted by the rotor to synthesize ATP molecules from their building blocks, ADP and phosphate. The synthetic motor can be uncoupled from the machine, and its rotary action can be studied by driving the motor backward with energy from ATP, releasing ADP and phosphate in the process. Each cycle has three 120° steps, each made of substeps of 65°, 25°, and 30° in humans. We have explained how release of phosphate from the machine generates the 25° rotary substep. The rotation of the central stalk of F1-ATPase is driven by energy derived from the sequential binding of an ATP molecule to its three catalytic sites and the release of the products of hydrolysis. In human F1-ATPase, each 360° rotation consists of three 120° steps composed of substeps of about 65°, 25°, and 30°, with intervening ATP binding, phosphate release, and catalytic dwells, respectively. The F1-ATPase inhibitor protein, IF1, halts the rotary cycle at the catalytic dwell. The human and bovine enzymes are essentially identical, and the structure of bovine F1-ATPase inhibited by IF1 represents the catalytic dwell state. Another structure, described here, of bovine F1-ATPase inhibited by an ATP analog and the phosphate analog, thiophosphate, represents the phosphate binding dwell. Thiophosphate is bound to a site in the αEβE-catalytic interface, whereas in F1-ATPase inhibited with IF1, the equivalent site is changed subtly and the enzyme is incapable of binding thiophosphate. These two structures provide a molecular mechanism of how phosphate release generates a rotary substep as follows. In the active enzyme, phosphate release from the βE-subunit is accompanied by a rearrangement of the structure of its binding site that prevents released phosphate from rebinding. The associated extrusion of a loop in the βE-subunit disrupts interactions in the αEβE-catalytic interface and opens it to its fullest extent. Other rearrangements disrupt interactions between the γ-subunit and the C-terminal domain of the αE-subunit. To restore most of these interactions, and to make compensatory new ones, the γ-subunit rotates through 25°–30°.
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96
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Bonora M, Wieckowski MR, Chinopoulos C, Kepp O, Kroemer G, Galluzzi L, Pinton P. Molecular mechanisms of cell death: central implication of ATP synthase in mitochondrial permeability transition. Oncogene 2015; 34:1475-86. [PMID: 24727893 DOI: 10.1038/onc.2014.96] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/20/2014] [Accepted: 02/27/2014] [Indexed: 12/14/2022]
Abstract
The term mitochondrial permeability transition (MPT) is commonly used to indicate an abrupt increase in the permeability of the inner mitochondrial membrane to low molecular weight solutes. Widespread MPT has catastrophic consequences for the cell, de facto marking the boundary between cellular life and death. MPT results indeed in the structural and functional collapse of mitochondria, an event that commits cells to suicide via regulated necrosis or apoptosis. MPT has a central role in the etiology of both acute and chronic diseases characterized by the loss of post-mitotic cells. Moreover, cancer cells are often relatively insensitive to the induction of MPT, underlying their increased resistance to potentially lethal cues. Thus, intense efforts have been dedicated not only at the understanding of MPT in mechanistic terms, but also at the development of pharmacological MPT modulators. In this setting, multiple mitochondrial and extramitochondrial proteins have been suspected to critically regulate the MPT. So far, however, only peptidylprolyl isomerase F (best known as cyclophilin D) appears to constitute a key component of the so-called permeability transition pore complex (PTPC), the supramolecular entity that is believed to mediate MPT. Here, after reviewing the structural and functional features of the PTPC, we summarize recent findings suggesting that another of its core components is represented by the c subunit of mitochondrial ATP synthase.
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Affiliation(s)
- M Bonora
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
| | - M R Wieckowski
- Department of Biochemistry, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - C Chinopoulos
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
| | - O Kepp
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - G Kroemer
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Metabolomics and Cell Biology platforms, Gustave Roussy Comprehensive Cancer Center, Villejuif, France [4] Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France
| | - L Galluzzi
- 1] Equipe 11 labelisée par la Ligue Nationale contre le cancer, INSERM U1138, Centre de Recherche des Cordeliers, Paris, France [2] Université Paris Descartes/Paris 5, Sorbonne Paris Cité, Paris, France [3] Gustave Roussy Comprehensive Cancer Center, Villejuif, France
| | - P Pinton
- Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Morphology, Surgery and Experimental Medicine, Interdisciplinary Centre for the Study of Inflammation (ICSI), University of Ferrara, Ferrara, Italy
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97
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Nesci S, Trombetti F, Ventrella V, Pagliarani A. Opposite rotation directions in the synthesis and hydrolysis of ATP by the ATP synthase: hints from a subunit asymmetry. J Membr Biol 2015; 248:163-9. [PMID: 25655107 DOI: 10.1007/s00232-014-9760-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 11/18/2014] [Indexed: 11/25/2022]
Abstract
The ATP synthase can be imagined as a reversible H(+)-translocating channel embedded in the membrane, FO portion, coupled to a protruding catalytic portion, F1. Under physiological conditions the F1FO complex synthesizes ATP by exploiting the transmembrane electrochemical gradient of protons and their downhill movement. Alternatively, under other patho-physiological conditions it exploits ATP hydrolysis to energize the membrane by uphill pumping protons. The reversibility of the mechanism is guaranteed by the structural coupling between the hydrophilic F1 and the hydrophobic FO. Which of the two opposite processes wins in the energy-transducing membrane complex depends on the thermodynamic balance between the protonmotive force (Δp) and the phosphorylation potential of ATP (ΔG P). Accordingly, while Δp prevalence drives ATP synthesis by translocating protons from the membrane P-side to the N-side and generating anticlockwise torque rotation (viewed from the matrix), ΔG P drives ATP hydrolysis by chemomechanical coupling of FO to F1 with clockwise torque. The direction of rotation is the same in all the ATP synthases, due to the conserved steric arrangement of the chiral a subunit of FO. The ability of this coupled bi-functional complex to produce opposite rotations in ATP synthesis and hydrolysis is explained on the basis of the a subunit asymmetry.
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Affiliation(s)
- Salvatore Nesci
- Department of Veterinary Medical Sciences, University of Bologna, Bologna, Italy
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98
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Zhou A, Rohou A, Schep DG, Bason JV, Montgomery MG, Walker JE, Grigorieff N, Rubinstein JL. Structure and conformational states of the bovine mitochondrial ATP synthase by cryo-EM. eLife 2015; 4:e10180. [PMID: 26439008 PMCID: PMC4718723 DOI: 10.7554/elife.10180] [Citation(s) in RCA: 225] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/05/2015] [Indexed: 02/02/2023] Open
Abstract
Adenosine triphosphate (ATP), the chemical energy currency of biology, is synthesized in eukaryotic cells primarily by the mitochondrial ATP synthase. ATP synthases operate by a rotary catalytic mechanism where proton translocation through the membrane-inserted FO region is coupled to ATP synthesis in the catalytic F1 region via rotation of a central rotor subcomplex. We report here single particle electron cryomicroscopy (cryo-EM) analysis of the bovine mitochondrial ATP synthase. Combining cryo-EM data with bioinformatic analysis allowed us to determine the fold of the a subunit, suggesting a proton translocation path through the FO region that involves both the a and b subunits. 3D classification of images revealed seven distinct states of the enzyme that show different modes of bending and twisting in the intact ATP synthase. Rotational fluctuations of the c8-ring within the FO region support a Brownian ratchet mechanism for proton-translocation-driven rotation in ATP synthases.
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Affiliation(s)
- Anna Zhou
- The Hospital for Sick Children Research Institute, Toronto, Canada,Department of Medical Biophysics, The University of Toronto, Ontario, Canada
| | - Alexis Rohou
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Daniel G Schep
- The Hospital for Sick Children Research Institute, Toronto, Canada,Department of Medical Biophysics, The University of Toronto, Ontario, Canada
| | - John V Bason
- MRC Mitochondrial Biology Unit, Cambridge, United Kingdom
| | | | - John E Walker
- MRC Mitochondrial Biology Unit, Cambridge, United Kingdom, (JEW)
| | - Nikolaus Grigorieff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States, (NG)
| | - John L Rubinstein
- The Hospital for Sick Children Research Institute, Toronto, Canada,Department of Medical Biophysics, The University of Toronto, Ontario, Canada,Department of Biochemistry, The University of Toronto, Ontario, Canada, (JLR)
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99
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Gutiérrez-Estrada A, Ramírez-Santos J, Gómez-Eichelmann MDC. Role of chaperones and ATP synthase in DNA gyrase reactivation in Escherichia coli stationary-phase cells after nutrient addition. SPRINGERPLUS 2014; 3:656. [PMID: 25485196 PMCID: PMC4230433 DOI: 10.1186/2193-1801-3-656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 10/29/2014] [Indexed: 12/03/2022]
Abstract
Escherichia coli stationary-phase (SP) cells contain relaxed DNA molecules and recover DNA supercoiling once nutrients become available. In these cells, the reactivation of DNA gyrase, which is a DNA topoisomerase type IIA enzyme, is responsible for the recovery of DNA supercoiling. The results presented in this study show that DNA gyrase reactivation does not require cellular chaperones or polyphosphate. Glucose addition to SP cells induced a slow recovery of DNA supercoiling, whereas resveratrol, which is an inhibitor of ATP synthase, inhibited the enzyme reactivation. These results suggest that DNA gyrase, which is an ATP-dependent enzyme, remains soluble in SP cells, and that its reactivation occurs primarily due to a rapid increase in the cellular ATP concentration.
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Affiliation(s)
- Alejandra Gutiérrez-Estrada
- Department of Molecular Biology and Biotechnology, Institute of Biomedical Research, National Autonomous University of México, P.O. Box 70228, México City, 04510 México
| | - Jesús Ramírez-Santos
- Department of Molecular Biology and Biotechnology, Institute of Biomedical Research, National Autonomous University of México, P.O. Box 70228, México City, 04510 México
| | - María Del Carmen Gómez-Eichelmann
- Department of Molecular Biology and Biotechnology, Institute of Biomedical Research, National Autonomous University of México, P.O. Box 70228, México City, 04510 México
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100
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Abstract
The biguanide metformin is widely prescribed for Type II diabetes and has anti-neoplastic activity in laboratory models. Despite evidence that inhibition of mitochondrial respiratory complex I by metformin is the primary cause of its cell-lineage-specific actions and therapeutic effects, the molecular interaction(s) between metformin and complex I remain uncharacterized. In the present paper, we describe the effects of five pharmacologically relevant biguanides on oxidative phosphorylation in mammalian mitochondria. We report that biguanides inhibit complex I by inhibiting ubiquinone reduction (but not competitively) and, independently, stimulate reactive oxygen species production by the complex I flavin. Biguanides also inhibit mitochondrial ATP synthase, and two of them inhibit only ATP hydrolysis, not synthesis. Thus we identify biguanides as a new class of complex I and ATP synthase inhibitor. By comparing biguanide effects on isolated complex I and cultured cells, we distinguish three anti-diabetic and potentially anti-neoplastic biguanides (metformin, buformin and phenformin) from two anti-malarial biguanides (cycloguanil and proguanil): the former are accumulated into mammalian mitochondria and affect oxidative phosphorylation, whereas the latter are excluded so act only on the parasite. Our mechanistic and pharmacokinetic insights are relevant to understanding and developing the role of biguanides in new and existing therapeutic applications, including cancer, diabetes and malaria.
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