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Zítek J, King MS, Peña-Diaz P, Pyrihová E, King AC, Kunji ERS, Hampl V. The free-living flagellate Paratrimastix pyriformis uses a distinct mitochondrial carrier to balance adenine nucleotide pools. Arch Biochem Biophys 2023; 742:109638. [PMID: 37192692 PMCID: PMC10251735 DOI: 10.1016/j.abb.2023.109638] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 05/12/2023] [Accepted: 05/13/2023] [Indexed: 05/18/2023]
Abstract
Paratrimastix pyriformis is a free-living flagellate thriving in low-oxygen freshwater sediments. It belongs to the group Metamonada along with human parasites, such as Giardia and Trichomonas. Like other metamonads, P. pyriformis has a mitochondrion-related organelle (MRO) which in this protist is primarily involved in one-carbon folate metabolism. The MRO contains four members of the solute carrier family 25 (SLC25) responsible for the exchange of metabolites across the mitochondrial inner membrane. Here, we characterise the function of the adenine nucleotide carrier PpMC1 by thermostability shift and transport assays. We show that it transports ATP, ADP and, to a lesser extent, AMP, but not phosphate. The carrier is distinct in function and origin from both ADP/ATP carriers and ATP-Mg/phosphate carriers, and it most likely represents a distinct class of adenine nucleotide carriers.
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Affiliation(s)
- Justyna Zítek
- Charles University, Faculty of Science, Department of Parasitology, BIOCEV, Vestec, 252 50, Czech Republic
| | - Martin S King
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Priscila Peña-Diaz
- Charles University, Faculty of Science, Department of Parasitology, BIOCEV, Vestec, 252 50, Czech Republic
| | - Eva Pyrihová
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom; University of Stavanger, Department of Chemistry, Bioscience, And Environmental Engineering, Richard Johnsens Gate 4, N-4021, Stavanger, Norway
| | - Alannah C King
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom.
| | - Vladimír Hampl
- Charles University, Faculty of Science, Department of Parasitology, BIOCEV, Vestec, 252 50, Czech Republic.
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Cimadamore-Werthein C, Jaiquel Baron S, King MS, Springett R, Kunji ER. Human mitochondrial ADP/ATP carrier SLC25A4 operates with a ping-pong kinetic mechanism. EMBO Rep 2023:e57127. [PMID: 37278158 PMCID: PMC10398649 DOI: 10.15252/embr.202357127] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/17/2023] [Accepted: 05/17/2023] [Indexed: 06/07/2023] Open
Abstract
The mitochondrial ADP/ATP carrier (SLC25A4), also called the adenine nucleotide translocase, imports ADP into the mitochondrial matrix and exports ATP, which are key steps in oxidative phosphorylation. Historically, the carrier was thought to form a homodimer and to operate by a sequential kinetic mechanism, which involves the formation of a ternary complex with the two exchanged substrates bound simultaneously. However, recent structural and functional data have demonstrated that the mitochondrial ADP/ATP carrier works as a monomer and has a single substrate binding site, which cannot be reconciled with a sequential kinetic mechanism. Here, we study the kinetic properties of the human mitochondrial ADP/ATP carrier by using proteoliposomes and transport robotics. We show that the Km/Vmax ratio is constant for all of the measured internal concentrations. Thus, in contrast to earlier claims, we conclude that the carrier operates with a ping-pong kinetic mechanism in which substrate exchange across the membrane occurs consecutively rather than simultaneously. These data unite the kinetic and structural models, showing that the carrier operates with an alternating access mechanism.
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Affiliation(s)
- Camila Cimadamore-Werthein
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK
| | - Stephany Jaiquel Baron
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK
| | - Martin S King
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK
| | | | - Edmund Rs Kunji
- Medical Research Council Mitochondrial Biology Unit, The Keith Peters Building, Cambridge Biomedical Campus, Cambridge, UK
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Jones SA, Gogoi P, Ruprecht JJ, King MS, Lee Y, Zögg T, Pardon E, Chand D, Steimle S, Copeman DM, Cotrim CA, Steyaert J, Crichton PG, Moiseenkova-Bell V, Kunji ER. Structural basis of purine nucleotide inhibition of human uncoupling protein 1. Sci Adv 2023; 9:eadh4251. [PMID: 37256948 PMCID: PMC10413660 DOI: 10.1126/sciadv.adh4251] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 04/24/2023] [Indexed: 06/02/2023]
Abstract
Mitochondrial uncoupling protein 1 (UCP1) gives brown adipose tissue of mammals its specialized ability to burn calories as heat for thermoregulation. When activated by fatty acids, UCP1 catalyzes the leak of protons across the mitochondrial inner membrane, short-circuiting the mitochondrion to generate heat, bypassing ATP synthesis. In contrast, purine nucleotides bind and inhibit UCP1, regulating proton leak by a molecular mechanism that is unclear. We present the cryo-electron microscopy structure of the GTP-inhibited state of UCP1, which is consistent with its nonconducting state. The purine nucleotide cross-links the transmembrane helices of UCP1 with an extensive interaction network. Our results provide a structural basis for understanding the specificity and pH dependency of the regulatory mechanism. UCP1 has retained all of the key functional and structural features required for a mitochondrial carrier-like transport mechanism. The analysis shows that inhibitor binding prevents the conformational changes that UCP1 uses to facilitate proton leak.
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Affiliation(s)
- Scott A. Jones
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Cambridge CB2 0XY, UK
| | - Prerana Gogoi
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Perelman School of Medicine, 10-124 Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104-5158, USA
| | - Jonathan J. Ruprecht
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Cambridge CB2 0XY, UK
| | - Martin S. King
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Cambridge CB2 0XY, UK
| | - Yang Lee
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Cambridge CB2 0XY, UK
| | - Thomas Zögg
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, B-1050 Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Els Pardon
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, B-1050 Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Deepak Chand
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Cambridge CB2 0XY, UK
| | - Stefan Steimle
- Department of Biochemistry and Biophysics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Danielle M. Copeman
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, UK
| | - Camila A. Cotrim
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, UK
| | - Jan Steyaert
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, B-1050 Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Paul G. Crichton
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich NR4 7TJ, UK
| | - Vera Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Perelman School of Medicine, 10-124 Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104-5158, USA
| | - Edmund R. S. Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Cambridge CB2 0XY, UK
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Mavridou V, King MS, Tavoulari S, Ruprecht JJ, Palmer SM, Kunji ERS. Substrate binding in the mitochondrial ADP/ATP carrier is a step-wise process guiding the structural changes in the transport cycle. Nat Commun 2022; 13:3585. [PMID: 35739110 PMCID: PMC9226169 DOI: 10.1038/s41467-022-31366-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 06/14/2022] [Indexed: 02/02/2023] Open
Abstract
Mitochondrial ADP/ATP carriers import ADP into the mitochondrial matrix and export ATP to the cytosol to fuel cellular processes. Structures of the inhibited cytoplasmic- and matrix-open states have confirmed an alternating access transport mechanism, but the molecular details of substrate binding remain unresolved. Here, we evaluate the role of the solvent-exposed residues of the translocation pathway in the process of substrate binding. We identify the main binding site, comprising three positively charged and a set of aliphatic and aromatic residues, which bind ADP and ATP in both states. Additionally, there are two pairs of asparagine/arginine residues on opposite sides of this site that are involved in substrate binding in a state-dependent manner. Thus, the substrates are directed through a series of binding poses, inducing the conformational changes of the carrier that lead to their translocation. The properties of this site explain the electrogenic and reversible nature of adenine nucleotide transport.
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Affiliation(s)
- Vasiliki Mavridou
- grid.5335.00000000121885934Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Hills Road, Cambridge, CB2 0XY UK
| | - Martin S. King
- grid.5335.00000000121885934Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Hills Road, Cambridge, CB2 0XY UK
| | - Sotiria Tavoulari
- grid.5335.00000000121885934Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Hills Road, Cambridge, CB2 0XY UK
| | - Jonathan J. Ruprecht
- grid.5335.00000000121885934Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Hills Road, Cambridge, CB2 0XY UK
| | - Shane M. Palmer
- grid.5335.00000000121885934Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Hills Road, Cambridge, CB2 0XY UK
| | - Edmund R. S. Kunji
- grid.5335.00000000121885934Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Keith Peters Building, Hills Road, Cambridge, CB2 0XY UK
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Tavoulari S, Schirris TJJ, Mavridou V, Thangaratnarajah C, King MS, Jones DTD, Ding S, Fearnley IM, Kunji ERS. Key features of inhibitor binding to the human mitochondrial pyruvate carrier hetero-dimer. Mol Metab 2022; 60:101469. [PMID: 35278701 PMCID: PMC8968063 DOI: 10.1016/j.molmet.2022.101469] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 02/28/2022] [Accepted: 03/01/2022] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The mitochondrial pyruvate carrier (MPC) has emerged as a promising drug target for metabolic disorders, including non-alcoholic steatohepatitis and diabetes, metabolically dependent cancers and neurodegenerative diseases. A range of structurally diverse small molecule inhibitors have been proposed, but the nature of their interaction with MPC is not understood, and the composition of the functional human MPC is still debated. The goal of this study was to characterise the human MPC protein in vitro, to understand the chemical features that determine binding of structurally diverse inhibitors and to develop novel higher affinity ones. METHODS We recombinantly expressed and purified human MPC hetero-complexes and studied their composition, transport and inhibitor binding properties by establishing in vitro transport assays, high throughput thermostability shift assays and pharmacophore modeling. RESULTS We determined that the functional unit of human MPC is a hetero-dimer. We compared all different classes of MPC inhibitors to find that three closely arranged hydrogen bond acceptors followed by an aromatic ring are shared characteristics of all inhibitors and represent the minimal requirement for high potency. We also demonstrated that high affinity binding is not attributed to covalent bond formation with MPC cysteines, as previously proposed. Following the basic pharmacophore properties, we identified 14 new inhibitors of MPC, one outperforming compound UK5099 by tenfold. Two are the commonly prescribed drugs entacapone and nitrofurantoin, suggesting an off-target mechanism associated with their adverse effects. CONCLUSIONS This work defines the composition of human MPC and the essential MPC inhibitor characteristics. In combination with the functional assays we describe, this new understanding will accelerate the development of clinically relevant MPC modulators.
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Affiliation(s)
- Sotiria Tavoulari
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom.
| | - Tom J J Schirris
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Vasiliki Mavridou
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Chancievan Thangaratnarajah
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Daniel T D Jones
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Shujing Ding
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Ian M Fearnley
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, United Kingdom.
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6
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Kunji ERS, King MS, Ruprecht JJ, Thangaratnarajah C. The SLC25 Carrier Family: Important Transport Proteins in Mitochondrial Physiology and Pathology. Physiology (Bethesda) 2021; 35:302-327. [PMID: 32783608 PMCID: PMC7611780 DOI: 10.1152/physiol.00009.2020] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Members of the mitochondrial carrier family (SLC25) transport a variety of compounds across the inner membrane of mitochondria. These transport steps provide building blocks for the cell and link the pathways of the mitochondrial matrix and cytosol. An increasing number of diseases and pathologies has been associated with their dysfunction. In this review, the molecular basis of these diseases is explained based on our current understanding of their transport mechanism.
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Affiliation(s)
- Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Jonathan J Ruprecht
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, United Kingdom
| | - Chancievan Thangaratnarajah
- Groningen Biomolecular Sciences and Biotechnology Institute, Membrane Enzymology, University of Groningen, Groningen, The Netherlands
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7
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Jaiquel Baron S, King MS, Kunji ER, Schirris TJ. Characterization of drug-induced human mitochondrial ADP/ATP carrier inhibition. Am J Cancer Res 2021; 11:5077-5091. [PMID: 33859735 PMCID: PMC8039944 DOI: 10.7150/thno.54936] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Accepted: 01/18/2021] [Indexed: 01/10/2023] Open
Abstract
An increasing number of commonly prescribed drugs are known to interfere with mitochondrial function, causing cellular toxicity, but the underlying mechanisms are largely unknown. Although often not considered, mitochondrial transport proteins form a significant class of potential mitochondrial off-targets. So far, most drug interactions have been reported for the mitochondrial ADP/ATP carrier (AAC), which exchanges cytosolic ADP for mitochondrial ATP. Here, we show inhibition of cellular respiratory capacity by only a subset of the 18 published AAC inhibitors, which questions whether all compound do indeed inhibit such a central metabolic process. This could be explained by the lack of a simple, direct model system to evaluate and compare drug-induced AAC inhibition. Methods: For its development, we have expressed and purified human AAC1 (hAAC1) and applied two approaches. In the first, thermostability shift assays were carried out to investigate the binding of these compounds to human AAC1. In the second, the effect of these compounds on transport was assessed in proteoliposomes with reconstituted human AAC1, enabling characterization of their inhibition kinetics. Results: Of the proposed inhibitors, chebulinic acid, CD-437 and suramin are the most potent with IC50-values in the low micromolar range, whereas another six are effective at a concentration of 100 μM. Remarkably, half of all previously published AAC inhibitors do not show significant inhibition in our assays, indicating that they are false positives. Finally, we show that inhibitor strength correlates with a negatively charged surface area of the inhibitor, matching the positively charged surface of the substrate binding site. Conclusion: Consequently, we have provided a straightforward model system to investigate AAC inhibition and have gained new insights into the chemical compound features important for inhibition. Better evaluation methods of drug-induced inhibition of mitochondrial transport proteins will contribute to the development of drugs with an enhanced safety profile.
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Diederichs KA, Ni X, Rollauer SE, Botos I, Tan X, King MS, Kunji E, Jiang J, Mindell JA, Buchanan SK. Towards Mechanistic Understanding of Mitochondrial β-Barrel Biogenesis: Structural Studies of the Sorting and Assembly Machinery. Biophys J 2021. [DOI: 10.1016/j.bpj.2020.11.763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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9
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Diederichs KA, Ni X, Rollauer SE, Botos I, Tan X, King MS, Kunji ERS, Jiang J, Buchanan SK. Structural insight into mitochondrial β-barrel outer membrane protein biogenesis. Nat Commun 2020; 11:3290. [PMID: 32620929 PMCID: PMC7335169 DOI: 10.1038/s41467-020-17144-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/13/2020] [Indexed: 11/09/2022] Open
Abstract
In mitochondria, β-barrel outer membrane proteins mediate protein import, metabolite transport, lipid transport, and biogenesis. The Sorting and Assembly Machinery (SAM) complex consists of three proteins that assemble as a 1:1:1 complex to fold β-barrel proteins and insert them into the mitochondrial outer membrane. We report cryoEM structures of the SAM complex from Myceliophthora thermophila, which show that Sam50 forms a 16-stranded transmembrane β-barrel with a single polypeptide-transport-associated (POTRA) domain extending into the intermembrane space. Sam35 and Sam37 are located on the cytosolic side of the outer membrane, with Sam35 capping Sam50, and Sam37 interacting extensively with Sam35. Sam35 and Sam37 each adopt a GST-like fold, with no functional, structural, or sequence similarity to their bacterial counterparts. Structural analysis shows how the Sam50 β-barrel opens a lateral gate to accommodate its substrates.
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Affiliation(s)
- Kathryn A Diederichs
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Xiaodan Ni
- Laboratory of Membrane Proteins and Structural Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Sarah E Rollauer
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
- Vertex Pharmaceuticals, 50 Northern Avenue, Boston, MA, 02210, USA
| | - Istvan Botos
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Xiaofeng Tan
- Laboratory of Membrane Proteins and Structural Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Martin S King
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
| | - Edmund R S Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0XY, UK
| | - Jiansen Jiang
- Laboratory of Membrane Proteins and Structural Biology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Susan K Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA.
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Abstract
Saccharomyces cerevisiae is one of the most popular expression systems for eukaryotic membrane proteins. Here, we describe protocols for the expression and purification of mitochondrial membrane proteins developed in our laboratory during the last 15 years. To optimize their expression in a functional form, different promoter systems as well as codon-optimization and complementation strategies were established. Purification approaches were developed which remove the membrane protein from the affinity column by specific proteolytic cleavage rather than by elution. This strategy has several important advantages, most notably improving the purity of the sample, as contaminants stay bound to the column, thus eliminating the need for a secondary purification step, such as size exclusion chromatography. This strategy also avoids dilution of the sample, which would occur as a consequence of elution, precluding the need for concentration steps, and thus preventing detergent concentration.
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Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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Boczonadi V, King MS, Smith AC, Olahova M, Bansagi B, Roos A, Eyassu F, Borchers C, Ramesh V, Lochmüller H, Polvikoski T, Whittaker RG, Pyle A, Griffin H, Taylor RW, Chinnery PF, Robinson AJ, Kunji ERS, Horvath R. Correction: Mitochondrial oxodicarboxylate carrier deficiency is associated with mitochondrial DNA depletion and spinal muscular atrophy-like disease. Genet Med 2019; 21:2163-2164. [PMID: 31028354 PMCID: PMC8075975 DOI: 10.1038/s41436-019-0506-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
This Article was originally published under Nature Research's License to Publish, but has now been made available under a [CC BY 4.0] license. The PDF and HTML versions of the Article have been modified accordingly.
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Affiliation(s)
- V Boczonadi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - M S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - A C Smith
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - M Olahova
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - B Bansagi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - A Roos
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
- Leibniz Institute of Analytic Sciences (ISAS), Dortmund, Germany
| | - F Eyassu
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - C Borchers
- UVic-Genome BC Proteomics Centre, Vancouver, BC, Canada
| | - V Ramesh
- Department of Paediatric Neurology, Royal Victoria Infirmary, Newcastle upon Tyne Foundation Hospitals NHS Trust, Newcastle upon Tyne, UK
| | - H Lochmüller
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - T Polvikoski
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - R G Whittaker
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - A Pyle
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - H Griffin
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - R W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - P F Chinnery
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - A J Robinson
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - E R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
| | - R Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
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12
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Ruprecht JJ, King MS, Zögg T, Aleksandrova AA, Pardon E, Crichton PG, Steyaert J, Kunji ERS. The Molecular Mechanism of Transport by the Mitochondrial ADP/ATP Carrier. Cell 2019; 176:435-447.e15. [PMID: 30611538 PMCID: PMC6349463 DOI: 10.1016/j.cell.2018.11.025] [Citation(s) in RCA: 176] [Impact Index Per Article: 35.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 09/25/2018] [Accepted: 11/16/2018] [Indexed: 11/30/2022]
Abstract
Mitochondrial ADP/ATP carriers transport ADP into the mitochondrial matrix for ATP synthesis, and ATP out to fuel the cell, by cycling between cytoplasmic-open and matrix-open states. The structure of the cytoplasmic-open state is known, but it has proved difficult to understand the transport mechanism in the absence of a structure in the matrix-open state. Here, we describe the structure of the matrix-open state locked by bongkrekic acid bound in the ADP/ATP-binding site at the bottom of the central cavity. The cytoplasmic side of the carrier is closed by conserved hydrophobic residues, and a salt bridge network, braced by tyrosines. Glycine and small amino acid residues allow close-packing of helices on the matrix side. Uniquely, the carrier switches between states by rotation of its three domains about a fulcrum provided by the substrate-binding site. Because these features are highly conserved, this mechanism is likely to apply to the whole mitochondrial carrier family. Video Abstract
Structure of the matrix-open state of the mitochondrial ADP/ATP carrier solved The inhibitor bongkrekic acid locks the state by occupying the substrate-binding site Conformational changes during transport are highly dynamic, using six mobile elements Roles of all conserved sequence features in mitochondrial carriers are now explained
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Affiliation(s)
- Jonathan J Ruprecht
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
| | - Martin S King
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Thomas Zögg
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Antoniya A Aleksandrova
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Els Pardon
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Paul G Crichton
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK
| | - Jan Steyaert
- VIB-VUB Center for Structural Biology, VIB, Pleinlaan 2, 1050 Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
| | - Edmund R S Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge CB2 0XY, UK.
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13
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King MS, Crichton PG, Ruprecht JJ, Kunji ERS. Publisher Correction: Concerns with yeast mitochondrial ADP/ATP carrier's integrity in DPC. Nat Struct Mol Biol 2018; 25:988. [PMID: 30218104 DOI: 10.1038/s41594-018-0138-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In the version of this article originally published, references 6 and 7 were interchanged in the reference list. The error has been corrected in the HTML and PDF versions of the article.
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Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Paul G Crichton
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Jonathan J Ruprecht
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
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14
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Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Paul G Crichton
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Jonathan J Ruprecht
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
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15
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King MS, Thompson K, Hopton S, He L, Kunji ERS, Taylor RW, Ortiz-Gonzalez XR. Expanding the phenotype of de novo SLC25A4-linked mitochondrial disease to include mild myopathy. Neurol Genet 2018; 4:e256. [PMID: 30046662 PMCID: PMC6055355 DOI: 10.1212/nxg.0000000000000256] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 05/15/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine the disease relevance of a novel de novo dominant variant in the SLC25A4 gene, encoding the muscle mitochondrial adenosine diphosphate (ADP)/adenosine triphosphate (ATP) carrier, identified in a child presenting with a previously unreported phenotype of mild childhood-onset myopathy. METHODS Immunohistochemical and western blot analysis of the patient's muscle tissue were used to assay for the evidence of mitochondrial myopathy and for complex I-V protein levels. To determine the effect of a putative pathogenic p.Lys33Gln variant on ADP/ATP transport, the mutant protein was expressed in Lactococcus lactis and its transport activity was assessed with fused membrane vesicles. RESULTS Our data demonstrate that the heterozygous c.97A>T (p.Lys33Gln) SLC25A4 variant is associated with classic muscle biopsy findings of mitochondrial myopathy (cytochrome c oxidase [COX]-deficient and ragged blue fibers), significantly impaired ADP/ATP transport in Lactococcus lactis and decreased complex I, III, and IV protein levels in patient's skeletal muscle. Nonetheless, the expression levels of the total ADP/ATP carrier (AAC) content in the muscle biopsy was largely unaffected. CONCLUSIONS This report further expands the clinical phenotype of de novo dominant SLC25A4 mutations to a childhood-onset, mild skeletal myopathy, without evidence of previously reported clinical features associated with SLC25A4-associated disease, such as cardiomyopathy, encephalopathy or ophthalmoplegia. The most likely reason for the milder disease phenotype is that the overall AAC expression levels were not affected, meaning that expression of the wild-type allele and other isoforms may in part have compensated for the impaired mutant variant.
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Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Kyle Thompson
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Sila Hopton
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Langping He
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Robert W Taylor
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
| | - Xilma R Ortiz-Gonzalez
- Medical Research Council Mitochondrial Biology Unit (M.S.K., E.R.S.K.), University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, UK; Wellcome Centre for Mitochondrial Research (K.T., S.H., L.H., R.W.D.), Institute of Neuroscience, Newcastle University, UK; and Department of Neurology (X.R.O.), Perelman School of Medicine, Division of Neurology and Center for Mitochondrial and Epigenomic Medicine, The Children's Hospital of Philadelphia, University of Pennsylvania
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16
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Mills EL, Ryan DG, Prag HA, Dikovskaya D, Menon D, Zaslona Z, Jedrychowski MP, Costa ASH, Higgins M, Hams E, Szpyt J, Runtsch MC, King MS, McGouran JF, Fischer R, Kessler BM, McGettrick AF, Hughes MM, Carroll RG, Booty LM, Knatko EV, Meakin PJ, Ashford MLJ, Modis LK, Brunori G, Sévin DC, Fallon PG, Caldwell ST, Kunji ERS, Chouchani ET, Frezza C, Dinkova-Kostova AT, Hartley RC, Murphy MP, O'Neill LA. Itaconate is an anti-inflammatory metabolite that activates Nrf2 via alkylation of KEAP1. Nature 2018; 556:113-117. [PMID: 29590092 PMCID: PMC6047741 DOI: 10.1038/nature25986] [Citation(s) in RCA: 978] [Impact Index Per Article: 163.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 02/09/2018] [Indexed: 02/02/2023]
Abstract
The endogenous metabolite itaconate has recently emerged as a regulator of macrophage function, but its precise mechanism of action remains poorly understood. Here we show that itaconate is required for the activation of the anti-inflammatory transcription factor Nrf2 (also known as NFE2L2) by lipopolysaccharide in mouse and human macrophages. We find that itaconate directly modifies proteins via alkylation of cysteine residues. Itaconate alkylates cysteine residues 151, 257, 288, 273 and 297 on the protein KEAP1, enabling Nrf2 to increase the expression of downstream genes with anti-oxidant and anti-inflammatory capacities. The activation of Nrf2 is required for the anti-inflammatory action of itaconate. We describe the use of a new cell-permeable itaconate derivative, 4-octyl itaconate, which is protective against lipopolysaccharide-induced lethality in vivo and decreases cytokine production. We show that type I interferons boost the expression of Irg1 (also known as Acod1) and itaconate production. Furthermore, we find that itaconate production limits the type I interferon response, indicating a negative feedback loop that involves interferons and itaconate. Our findings demonstrate that itaconate is a crucial anti-inflammatory metabolite that acts via Nrf2 to limit inflammation and modulate type I interferons.
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Affiliation(s)
- Evanna L Mills
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
- GlaxoSmithKline, Gunnelswood Road, Stevenage, Hertfordshire, UK
| | - Dylan G Ryan
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Hiran A Prag
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Dina Dikovskaya
- Jacqui Wood Cancer Centre, Division of Cancer Research, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Deepthi Menon
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Zbigniew Zaslona
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Mark P Jedrychowski
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Ana S H Costa
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Box 197, Cambridge Biomedical Campus, Cambridge CB2 0XZ, UK
| | - Maureen Higgins
- Jacqui Wood Cancer Centre, Division of Cancer Research, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Emily Hams
- School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - John Szpyt
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Marah C Runtsch
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Martin S King
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Joanna F McGouran
- School of Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Roman Fischer
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Benedikt M Kessler
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Anne F McGettrick
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Mark M Hughes
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Richard G Carroll
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
- GlaxoSmithKline, Gunnelswood Road, Stevenage, Hertfordshire, UK
| | - Lee M Booty
- GlaxoSmithKline, Gunnelswood Road, Stevenage, Hertfordshire, UK
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Elena V Knatko
- Jacqui Wood Cancer Centre, Division of Cancer Research, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Paul J Meakin
- Division of Molecular and Clinical Medicine, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Michael L J Ashford
- Division of Molecular and Clinical Medicine, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
| | - Louise K Modis
- GlaxoSmithKline, Gunnelswood Road, Stevenage, Hertfordshire, UK
| | - Gino Brunori
- GlaxoSmithKline, Park Road, Ware, Hertfordshire, UK
| | | | - Padraic G Fallon
- School of Medicine, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
| | - Stuart T Caldwell
- WestCHEM School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| | - Edmund R S Kunji
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Edward T Chouchani
- Department of Cancer Biology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Christian Frezza
- MRC Cancer Unit, University of Cambridge, Hutchison/MRC Research Centre, Box 197, Cambridge Biomedical Campus, Cambridge CB2 0XZ, UK
| | - Albena T Dinkova-Kostova
- Jacqui Wood Cancer Centre, Division of Cancer Research, School of Medicine, University of Dundee, Dundee DD1 9SY, UK
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Richard C Hartley
- WestCHEM School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge CB2 0XY, UK
| | - Luke A O'Neill
- School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin, Ireland
- GlaxoSmithKline, Gunnelswood Road, Stevenage, Hertfordshire, UK
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17
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Boczonadi V, King MS, Smith AC, Olahova M, Bansagi B, Roos A, Eyassu F, Borchers C, Ramesh V, Lochmüller H, Polvikoski T, Whittaker RG, Pyle A, Griffin H, Taylor RW, Chinnery PF, Robinson AJ, Kunji ERS, Horvath R. Mitochondrial oxodicarboxylate carrier deficiency is associated with mitochondrial DNA depletion and spinal muscular atrophy-like disease. Genet Med 2018. [PMID: 29517768 PMCID: PMC6004311 DOI: 10.1038/gim.2017.251] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Purpose Members of the mitochondrial carrier family (SLC25) transport metabolites, nucleotides, co-factors and inorganic ions across the mitochondrial inner membrane. Methods We identified a pathogenic variant in a novel mitochondrial carrier gene in a patient by whole exome sequencing. The pathogenicity of the mutation was studied by transport assays, computer modelling followed by targeted metabolic testing and in vitro studies in human fibroblasts and neurons. Results The patient carries a homozygous pathogenic variant c.695A>G; p.(Lys232Arg) in the SLC25A21 gene, encoding the mitochondrial oxodicarboxylate carrier, and developed spinal muscular atrophy and mitochondrial myopathy. Transport assays show that the mutation renders SLC25A21 dysfunctional and 2-oxoadipate cannot be imported into the mitochondrial matrix. Computer models of central metabolism predicted that impaired transport of oxodicarboxylate disrupts the pathways of lysine and tryptophan degradation, and causes accumulation of 2-oxoadipate, pipecolic acid and quinolinic acid, which was confirmed in the patient’s urine by targeted metabolomics. Exposure to 2-oxoadipate and quinolinic acid decreased the level of mitochondrial complexes in neuronal cells (SH-SY5Y) and induced apoptosis. Conclusion Mitochondrial oxodicarboxylate carrier deficiency leads to mitochondrial dysfunction and the accumulation of oxoadipate and quinolinic acid, which in turn cause toxicity in spinal motor neurons leading to spinal muscular atrophy-like disease.
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Affiliation(s)
- Veronika Boczonadi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Anthony C Smith
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Monika Olahova
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Boglarka Bansagi
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Andreas Roos
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Leibniz Institute of Analytic Sciences (ISAS), Dortmund, Germany
| | - Filmon Eyassu
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | | | - Venkateswaran Ramesh
- Department of Paediatric Neurology, Royal Victoria Infirmary, Newcastle upon Tyne Foundation Hospitals NHS Trust, Newcastle upon Tyne, UK
| | - Hanns Lochmüller
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Tuomo Polvikoski
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Roger G Whittaker
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Angela Pyle
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Helen Griffin
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Patrick F Chinnery
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.,Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Alan J Robinson
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK.
| | - Rita Horvath
- Wellcome Centre for Mitochondrial Research, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.
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18
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Kurauskas V, Hessel A, Ma P, Lunetti P, Weinhäupl K, Imbert L, Brutscher B, King MS, Sounier R, Dolce V, Kunji ERS, Capobianco L, Chipot C, Dehez F, Bersch B, Schanda P. How Detergent Impacts Membrane Proteins: Atomic-Level Views of Mitochondrial Carriers in Dodecylphosphocholine. J Phys Chem Lett 2018; 9:933-938. [PMID: 29397729 PMCID: PMC5834942 DOI: 10.1021/acs.jpclett.8b00269] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 02/02/2018] [Indexed: 05/30/2023]
Abstract
Characterizing the structure of membrane proteins (MPs) generally requires extraction from their native environment, most commonly with detergents. Yet, the physicochemical properties of detergent micelles and lipid bilayers differ markedly and could alter the structural organization of MPs, albeit without general rules. Dodecylphosphocholine (DPC) is the most widely used detergent for MP structure determination by NMR, but the physiological relevance of several prominent structures has been questioned, though indirectly, by other biophysical techniques, e.g., functional/thermostability assay (TSA) and molecular dynamics (MD) simulations. Here, we resolve unambiguously this controversy by probing the functional relevance of three different mitochondrial carriers (MCs) in DPC at the atomic level, using an exhaustive set of solution-NMR experiments, complemented by functional/TSA and MD data. Our results provide atomic-level insight into the structure, substrate interaction and dynamics of the detergent-membrane protein complexes and demonstrates cogently that, while high-resolution NMR signals can be obtained for MCs in DPC, they systematically correspond to nonfunctional states.
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Affiliation(s)
- Vilius Kurauskas
- Université
Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Audrey Hessel
- Université
Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Peixiang Ma
- Université
Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Paola Lunetti
- Department
of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | | | - Lionel Imbert
- Université
Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | | | - Martin S. King
- MRC-MBU, University of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Rémy Sounier
- CNRS,
INSERM, Université de Montpellier, 34094 Montpellier, France
| | - Vincenza Dolce
- Dept
of Pharmacy, University of Calabria, 87036 Arcavacata
di Rende, Italy
| | | | - Loredana Capobianco
- Department
of Biological and Environmental Sciences and Technologies, University of Salento, 73100 Lecce, Italy
| | - Christophe Chipot
- LPCT, UMR
7019 Université de Lorraine, CNRS and Laboratoire International
Associé & University of Illinois at Urbana−Champaign, F-54500 Vandoeuvre-lès-Nancy, France
| | - François Dehez
- LPCT, UMR
7019 Université de Lorraine, CNRS and Laboratoire International
Associé & University of Illinois at Urbana−Champaign, F-54500 Vandoeuvre-lès-Nancy, France
| | - Beate Bersch
- Université
Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
| | - Paul Schanda
- Université
Grenoble Alpes, CNRS, CEA, IBS, 38000 Grenoble, France
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19
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Majd H, King MS, Palmer SM, Smith AC, Elbourne LDH, Paulsen IT, Sharples D, Henderson PJF, Kunji ERS. Screening of candidate substrates and coupling ions of transporters by thermostability shift assays. eLife 2018; 7:38821. [PMID: 30320551 PMCID: PMC6211832 DOI: 10.7554/elife.38821] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/11/2018] [Indexed: 02/02/2023] Open
Abstract
Substrates of most transport proteins have not been identified, limiting our understanding of their role in physiology and disease. Traditional identification methods use transport assays with radioactive compounds, but they are technically challenging and many compounds are unavailable in radioactive form or are prohibitively expensive, precluding large-scale trials. Here, we present a high-throughput screening method that can identify candidate substrates from libraries of unlabeled compounds. The assay is based on the principle that transport proteins recognize substrates through specific interactions, which lead to enhanced stabilization of the transporter population in thermostability shift assays. Representatives of three different transporter (super)families were tested, which differ in structure as well as transport and ion coupling mechanisms. In each case, the substrates were identified correctly from a large set of chemically related compounds, including stereo-isoforms. In some cases, stabilization by substrate binding was enhanced further by ions, providing testable hypotheses on energy coupling mechanisms.
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Affiliation(s)
- Homa Majd
- Medical Research Council Mitochondrial Biology UnitUniversity of CambridgeCambridgeUnited Kingdom
| | - Martin S King
- Medical Research Council Mitochondrial Biology UnitUniversity of CambridgeCambridgeUnited Kingdom
| | - Shane M Palmer
- Medical Research Council Mitochondrial Biology UnitUniversity of CambridgeCambridgeUnited Kingdom
| | - Anthony C Smith
- Medical Research Council Mitochondrial Biology UnitUniversity of CambridgeCambridgeUnited Kingdom
| | - Liam DH Elbourne
- Department of Molecular SciencesMacquarie UniversitySydneyAustralia
| | - Ian T Paulsen
- Department of Molecular SciencesMacquarie UniversitySydneyAustralia
| | - David Sharples
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsUnited Kingdom,School of Biomedical SciencesUniversity of LeedsLeedsUnited Kingdom
| | - Peter JF Henderson
- Astbury Centre for Structural Molecular BiologyUniversity of LeedsLeedsUnited Kingdom,School of Biomedical SciencesUniversity of LeedsLeedsUnited Kingdom
| | - Edmund RS Kunji
- Medical Research Council Mitochondrial Biology UnitUniversity of CambridgeCambridgeUnited Kingdom
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20
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Majd H, King MS, Smith AC, Kunji ERS. Pathogenic mutations of the human mitochondrial citrate carrier SLC25A1 lead to impaired citrate export required for lipid, dolichol, ubiquinone and sterol synthesis. Biochim Biophys Acta Bioenerg 2018; 1859:1-7. [PMID: 29031613 DOI: 10.1016/j.bbabio.2017.10.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/03/2017] [Accepted: 10/09/2017] [Indexed: 11/22/2022]
Abstract
Missense mutations of the human mitochondrial citrate carrier, encoded by the SLC25A1 gene, lead to an autosomal recessive neurometabolic disorder characterised by neonatal-onset encephalopathy with severe muscular weakness, intractable seizures, respiratory distress, and lack of psychomotor development, often resulting in early death. Here, we have measured the effect of all twelve known pathogenic mutations on the transport activity. The results show that nine mutations abolish transport of citrate completely, whereas the other three reduce the transport rate by >70%, indicating that impaired citrate transport is the most likely primary cause of the disease. Some mutations may be detrimental to the structure of the carrier, whereas others may impair key functional elements, such as the substrate binding site and the salt bridge network on the matrix side of the carrier. To understand the consequences of impaired citrate transport on metabolism, the substrate specificity was also determined, showing that the human citrate carrier predominantly transports citrate, isocitrate, cis-aconitate, phosphoenolpyruvate and malate. Although D-2- and L-2 hydroxyglutaric aciduria is a metabolic hallmark of the disease, it is unlikely that the citrate carrier plays a significant role in the removal of hydroxyglutarate from the cytosol for oxidation to oxoglutarate in the mitochondrial matrix. In contrast, computer simulations of central metabolism predict that the export of citrate from the mitochondrion cannot be fully compensated by other pathways, restricting the cytosolic production of acetyl-CoA that is required for the synthesis of lipids, sterols, dolichols and ubiquinone, which in turn explains the severe disease phenotypes.
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Affiliation(s)
- Homa Majd
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Martin S King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Anthony C Smith
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK.
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Dehez F, Schanda P, King MS, Kunji ERS, Chipot C. Mitochondrial ADP/ATP Carrier in Dodecylphosphocholine Binds Cardiolipins with Non-native Affinity. Biophys J 2017; 113:2311-2315. [PMID: 29056231 PMCID: PMC5722206 DOI: 10.1016/j.bpj.2017.09.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/12/2017] [Accepted: 09/21/2017] [Indexed: 12/11/2022] Open
Abstract
Biophysical investigation of membrane proteins generally requires their extraction from native sources using detergents, a step that can lead, possibly irreversibly, to protein denaturation. The propensity of dodecylphosphocholine (DPC), a detergent widely utilized in NMR studies of membrane proteins, to distort their structure has been the subject of much controversy. It has been recently proposed that the binding specificity of the yeast mitochondrial ADP/ATP carrier (yAAC3) toward cardiolipins is preserved in DPC, thereby suggesting that DPC is a suitable environment in which to study membrane proteins. In this communication, we used all-atom molecular dynamics simulations to investigate the specific binding of cardiolipins to yAAC3. Our data demonstrate that the interaction interface observed in a native-like environment differs markedly from that inferred from an NMR investigation in DPC, implying that in this detergent, the protein structure is distorted. We further investigated yAAC3 solubilized in DPC and in the milder dodecylmaltoside with thermal-shift assays. The loss of thermal transition observed in DPC confirms that the protein is no longer properly folded in this environment.
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Affiliation(s)
- François Dehez
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche no. 7565, Université de Lorraine, Vandœuvre-lès-Nancy, France
| | - Paul Schanda
- Université Grenoble Alpes, CEA, CNRS, Institut de Biologie Structurale, Grenoble, France.
| | - Martin S King
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Edmund R S Kunji
- Medical Research Council, Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, United Kingdom
| | - Christophe Chipot
- Laboratoire International Associé Centre National de la Recherche Scientifique et University of Illinois at Urbana-Champaign, Unité Mixte de Recherche no. 7565, Université de Lorraine, Vandœuvre-lès-Nancy, France; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois.
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Harborne SPD, King MS, Crichton PG, Kunji ERS. Calcium regulation of the human mitochondrial ATP-Mg/Pi carrier SLC25A24 uses a locking pin mechanism. Sci Rep 2017; 7:45383. [PMID: 28350015 PMCID: PMC5369052 DOI: 10.1038/srep45383] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/22/2017] [Indexed: 12/18/2022] Open
Abstract
Mitochondrial ATP-Mg/Pi carriers import adenine nucleotides into the mitochondrial matrix and export phosphate to the cytosol. They are calcium-regulated to control the size of the matrix adenine nucleotide pool in response to cellular energetic demands. They consist of three domains: an N-terminal regulatory domain containing four calcium-binding EF-hands, a linker loop domain with an amphipathic α-helix and a C-terminal mitochondrial carrier domain for the transport of substrates. Here, we use thermostability assays to demonstrate that the carrier is regulated by calcium via a locking pin mechanism involving the amphipathic α-helix. When calcium levels in the intermembrane space are high, the N-terminus of the amphipathic α-helix is bound to a cleft in the regulatory domain, leading to substrate transport by the carrier domain. When calcium levels drop, the cleft closes, and the amphipathic α-helix is released to bind to the carrier domain via its C-terminus, locking the carrier in an inhibited state.
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Affiliation(s)
- Steven P. D. Harborne
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
- School of Biomedical Sciences and Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, LS2 9JT, UK
| | - Martin S. King
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Paul G. Crichton
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK
| | - Edmund R. S. Kunji
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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23
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King MS, Kerr M, Crichton PG, Springett R, Kunji ERS. Corrigendum to "Formation of a cytoplasmic salt bridge network in the matrix state is a fundamental step in the transport mechanism of the mitochondrial ADP/ATP carrier" [Biochim. Biophys. Acta 1857 (2016) 14-22]. Biochim Biophys Acta 2016; 1857:1949. [PMID: 27705820 PMCID: PMC5084680 DOI: 10.1016/j.bbabio.2016.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Matthew Kerr
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Paul G Crichton
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Roger Springett
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK.
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Kunji ERS, Aleksandrova A, King MS, Majd H, Ashton VL, Cerson E, Springett R, Kibalchenko M, Tavoulari S, Crichton PG, Ruprecht JJ. Corrigendum to "The transport mechanism of the mitochondrial ADP/ATP carrier" [Biochim. Biophys. Acta 1863/10 (2016) 2379-2393]. Biochim Biophys Acta 2016; 1863:3169. [PMID: 27713079 DOI: 10.1016/j.bbamcr.2016.09.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Edmund R S Kunji
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK.
| | - Antoniya Aleksandrova
- TCM Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Martin S King
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Homa Majd
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Valerie L Ashton
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Elizabeth Cerson
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Roger Springett
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Mikhail Kibalchenko
- TCM Group, Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, United Kingdom
| | - Sotiria Tavoulari
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Paul G Crichton
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Jonathan J Ruprecht
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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Thompson K, Majd H, Dallabona C, Reinson K, King MS, Alston CL, He L, Lodi T, Jones SA, Fattal-Valevski A, Fraenkel ND, Saada A, Haham A, Isohanni P, Vara R, Barbosa IA, Simpson MA, Deshpande C, Puusepp S, Bonnen PE, Rodenburg RJ, Suomalainen A, Õunap K, Elpeleg O, Ferrero I, McFarland R, Kunji ERS, Taylor RW. Recurrent De Novo Dominant Mutations in SLC25A4 Cause Severe Early-Onset Mitochondrial Disease and Loss of Mitochondrial DNA Copy Number. Am J Hum Genet 2016; 99:860-876. [PMID: 27693233 PMCID: PMC5065686 DOI: 10.1016/j.ajhg.2016.08.014] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/18/2016] [Indexed: 11/26/2022] Open
Abstract
Mutations in SLC25A4 encoding the mitochondrial ADP/ATP carrier AAC1 are well-recognized causes of mitochondrial disease. Several heterozygous SLC25A4 mutations cause adult-onset autosomal-dominant progressive external ophthalmoplegia associated with multiple mitochondrial DNA deletions, whereas recessive SLC25A4 mutations cause childhood-onset mitochondrial myopathy and cardiomyopathy. Here, we describe the identification by whole-exome sequencing of seven probands harboring dominant, de novo SLC25A4 mutations. All affected individuals presented at birth, were ventilator dependent and, where tested, revealed severe combined mitochondrial respiratory chain deficiencies associated with a marked loss of mitochondrial DNA copy number in skeletal muscle. Strikingly, an identical c.239G>A (p.Arg80His) mutation was present in four of the seven subjects, and the other three case subjects harbored the same c.703C>G (p.Arg235Gly) mutation. Analysis of skeletal muscle revealed a marked decrease of AAC1 protein levels and loss of respiratory chain complexes containing mitochondrial DNA-encoded subunits. We show that both recombinant AAC1 mutant proteins are severely impaired in ADP/ATP transport, affecting most likely the substrate binding and mechanics of the carrier, respectively. This highly reduced capacity for transport probably affects mitochondrial DNA maintenance and in turn respiration, causing a severe energy crisis. The confirmation of the pathogenicity of these de novo SLC25A4 mutations highlights a third distinct clinical phenotype associated with mutation of this gene and demonstrates that early-onset mitochondrial disease can be caused by recurrent de novo mutations, which has significant implications for the application and analysis of whole-exome sequencing data in mitochondrial disease.
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Affiliation(s)
- Kyle Thompson
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Homa Majd
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Cristina Dallabona
- Department of Life Sciences, University of Parma, Parco Area delle Scienze 11A, Parma 43124, Italy
| | - Karit Reinson
- Department of Pediatrics, Institute of Clinical Medicine, University of Tartu, 51014 Tartu, Estonia; Department of Genetics, United Laboratories, Tartu University Hospital, 51014 Tartu, Estonia
| | - Martin S King
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Charlotte L Alston
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Langping He
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Tiziana Lodi
- Department of Life Sciences, University of Parma, Parco Area delle Scienze 11A, Parma 43124, Italy
| | - Simon A Jones
- Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, St Marys Hospital, Oxford Road, Manchester M13 9WL, UK
| | - Aviva Fattal-Valevski
- Paediatric Neurology Unit, "Dana" Children Hospital, Tel Aviv Sourasky Medical Centre, Sackler Faculty of Medicine, Tel Aviv University, 64239 Tel Aviv, Israel
| | - Nitay D Fraenkel
- Department of Respiratory Rehabilitation, Alyn Hospital, Jerusalem 91090, Israel
| | - Ann Saada
- Metabolic Laboratory Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Alon Haham
- Neonatal Intensive Care Unit, "Lis" Maternity Hospital, Tel Aviv Sourasky Medical Centre, 64239 Tel Aviv, Israel
| | - Pirjo Isohanni
- Research Programs Unit, Molecular Neurology, Biomedicum-Helsinki, University of Helsinki, 00290 Helsinki, Finland; Department of Pediatric Neurology, Children's Hospital, Helsinki University Hospital and University of Helsinki, 00290 Helsinki, Finland
| | - Roshni Vara
- Department of Paediatric Inherited Metabolic Diseases, Evelina Children's Hospital, London SE1 7EH, UK
| | - Inês A Barbosa
- Division of Genetics and Molecular Medicine, King's College London School of Medicine, London SE1 9RY, UK
| | - Michael A Simpson
- Division of Genetics and Molecular Medicine, King's College London School of Medicine, London SE1 9RY, UK
| | - Charu Deshpande
- Clinical Genetics Unit, Guys and St Thomas' NHS Foundation Trust, London SE1 9RT, UK
| | - Sanna Puusepp
- Department of Pediatrics, Institute of Clinical Medicine, University of Tartu, 51014 Tartu, Estonia; Department of Genetics, United Laboratories, Tartu University Hospital, 51014 Tartu, Estonia
| | - Penelope E Bonnen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Richard J Rodenburg
- Radboud Center for Mitochondrial Medicine, Department of Paediatrics, Translational Metabolic Laboratory, Radboud University Medical Centre, 6525 GA Nijmegen, the Netherlands
| | - Anu Suomalainen
- Research Programs Unit, Molecular Neurology, Biomedicum-Helsinki, University of Helsinki, 00290 Helsinki, Finland; Department of Neurosciences, Helsinki University Hospital and University of Helsinki, 00290 Helsinki, Finland
| | - Katrin Õunap
- Department of Pediatrics, Institute of Clinical Medicine, University of Tartu, 51014 Tartu, Estonia; Department of Genetics, United Laboratories, Tartu University Hospital, 51014 Tartu, Estonia
| | - Orly Elpeleg
- The Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
| | - Ileana Ferrero
- Department of Life Sciences, University of Parma, Parco Area delle Scienze 11A, Parma 43124, Italy
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
| | - Edmund R S Kunji
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
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Seigneurin-Berny D, King MS, Sautron E, Moyet L, Catty P, André F, Rolland N, Kunji ERS, Frelet-Barrand A. Membrane Protein Production in Lactococcus lactis for Functional Studies. Methods Mol Biol 2016; 1432:79-101. [PMID: 27485331 DOI: 10.1007/978-1-4939-3637-3_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Due to their unique properties, expression and study of membrane proteins in heterologous systems remains difficult. Among the bacterial systems available, the Gram-positive lactic bacterium, Lactococcus lactis, traditionally used in food fermentations, is nowadays widely used for large-scale production and functional characterization of bacterial and eukaryotic membrane proteins. The aim of this chapter is to describe the different possibilities for the functional characterization of peripheral or intrinsic membrane proteins expressed in Lactococcus lactis.
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Affiliation(s)
- Daphne Seigneurin-Berny
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS (UMR-5168)/CEA/INRA (UMR1417)/Université Grenoble Alpes, BIG, CEA, Grenoble, France
| | - Martin S King
- Medical Research Council, Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 2XY, UK
| | - Emiline Sautron
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS (UMR-5168)/CEA/INRA (UMR1417)/Université Grenoble Alpes, BIG, CEA, Grenoble, France
| | - Lucas Moyet
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS (UMR-5168)/CEA/INRA (UMR1417)/Université Grenoble Alpes, BIG, CEA, Grenoble, France
| | - Patrice Catty
- Laboratoire de Chimie et Biologie des Métaux, CNRS (UMR-5249)/CEA/Université Grenoble Alpes, BIG, CEA, Grenoble, France
| | - François André
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris Saclay, Gif-sur-Yvette, France
| | - Norbert Rolland
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS (UMR-5168)/CEA/INRA (UMR1417)/Université Grenoble Alpes, BIG, CEA, Grenoble, France
| | - Edmund R S Kunji
- Medical Research Council, Mitochondrial Biology Unit, Hills Road, Cambridge, CB2 2XY, UK
| | - Annie Frelet-Barrand
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris-Sud, Université Paris Saclay, Gif-sur-Yvette, France. .,FEMTO-ST Institute, UMR CNRS 6174, University of Bourgogne Franche-Comte, Besançon, France.
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King MS, Kerr M, Crichton PG, Springett R, Kunji ERS. Formation of a cytoplasmic salt bridge network in the matrix state is a fundamental step in the transport mechanism of the mitochondrial ADP/ATP carrier. Biochim Biophys Acta 2015; 1857:14-22. [PMID: 26453935 PMCID: PMC4674015 DOI: 10.1016/j.bbabio.2015.09.013] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 09/15/2015] [Accepted: 09/30/2015] [Indexed: 02/02/2023]
Abstract
Mitochondrial ADP/ATP carriers catalyze the equimolar exchange of ADP and ATP across the mitochondrial inner membrane. Structurally, they consist of three homologous domains with a single substrate binding site. They alternate between a cytoplasmic and matrix state in which the binding site is accessible to these compartments for binding of ADP or ATP. It has been proposed that cycling between states occurs by disruption and formation of a matrix and cytoplasmic salt bridge network in an alternating way, but formation of the latter has not been shown experimentally. Here, we show that state-dependent formation of the cytoplasmic salt bridge network can be demonstrated by measuring the effect of mutations on the thermal stability of detergent-solubilized carriers locked in a specific state. For this purpose, mutations were made to increase or decrease the overall interaction energy of the cytoplasmic network. When locked in the cytoplasmic state by the inhibitor carboxyatractyloside, the thermostabilities of the mutant and wild-type carriers were similar, but when locked in the matrix state by the inhibitor bongkrekic acid, they correlated with the predicted interaction energy of the cytoplasmic network, demonstrating its formation. Changing the interaction energy of the cytoplasmic network also had a profound effect on the kinetics of transport, indicating that formation of the network is a key step in the transport cycle. These results are consistent with a unique alternating access mechanism that involves the simultaneous rotation of the three domains around a central translocation pathway. Mitochondrial ADP/ATP carriers alternate between the matrix and cytoplasmic state. Matrix and cytoplasmic salt bridge networks regulate access to central binding site. Thermostability assays are used to probe state-dependent interactions in carriers. Cytoplasmic salt bridge network mutations only affect matrix state thermostability. Formation of the cytoplasmic network is a fundamental step in the transport cycle.
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Affiliation(s)
- Martin S King
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Matthew Kerr
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Paul G Crichton
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Roger Springett
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK.
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Abstract
The Gram-positive bacterium Lactococcus lactis has many properties that are ideal for the overproduction of membrane proteins in a functional form. Growth of lactococci is rapid, proceeds to high cell densities, and does not require aeration, which facilitates large-scale fermentation. The available promoter systems are strong and tightly regulated, allowing expression of toxic gene products in a controlled manner. Expressed membrane proteins are targeted exclusively to the cytoplasmic membrane, allowing the use of ionophores, ligands, and inhibitors to study activity of the membrane protein in whole cells. Constructed plasmids are stable and expression levels are highly reproducible. The relatively small genome size of the organism causes little redundancy, which facilitates complementation studies and allows for easier purification. The produced membrane proteins are often stable, as the organism has limited proteolytic capability, and they are readily solubilized from the membrane with mild detergents. Lactococci are multiple amino acid auxotrophs, allowing the incorporation of labels, such as selenomethionine. Among the few disadvantages are the low transformation frequency, AT-rich codon usage, and resistance to lysis by mechanical means, but these problems can be overcome fairly easily. We will describe in detail the protocols used to express membrane proteins in L. lactis, from cloning of the target gene to the isolation of membrane vesicles for the determination of expression levels.
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Affiliation(s)
- Martin S King
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Christoph Boes
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Edmund R S Kunji
- The Medical Research Council, Mitochondrial Biology Unit, Cambridge, United Kingdom.
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29
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Crichton PG, Lee Y, Ruprecht JJ, Cerson E, Thangaratnarajah C, King MS, Kunji ERS. Trends in thermostability provide information on the nature of substrate, inhibitor, and lipid interactions with mitochondrial carriers. J Biol Chem 2015; 290:8206-17. [PMID: 25653283 PMCID: PMC4375477 DOI: 10.1074/jbc.m114.616607] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial carriers, including uncoupling proteins, are unstable in detergents, which hampers structural and mechanistic studies. To investigate carrier stability, we have purified ligand-free carriers and assessed their stability with a fluorescence-based thermostability assay that monitors protein unfolding with a thiol-reactive dye. We find that mitochondrial carriers from both mesophilic and thermophilic organisms exhibit poor stability in mild detergents, indicating that instability is inherent to the protein family. Trends in the thermostability of yeast ADP/ATP carrier AAC2 and ovine uncoupling protein UCP1 allow optimal conditions for stability in detergents to be established but also provide mechanistic insights into the interactions of lipids, substrates, and inhibitors with these proteins. Both proteins exhibit similar stability profiles across various detergents, where stability increases with the size of the associated detergent micelle. Detailed analysis shows that lipids stabilize carriers indirectly by increasing the associated detergent micelle size, but cardiolipin stabilizes by direct interactions as well. Cardiolipin reverses destabilizing effects of ADP and bongkrekic acid on AAC2 and enhances large stabilizing effects of carboxyatractyloside, revealing that this lipid interacts in the m-state and possibly other states of the transport cycle, despite being in a dynamic interface. Fatty acid activators destabilize UCP1 in a similar way, which can also be prevented by cardiolipin, indicating that they interact like transport substrates. Our controls show that carriers can be soluble but unfolded in some commonly used detergents, such as the zwitterionic Fos-choline-12, which emphasizes the need for simple validation assays like the one used here.
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Affiliation(s)
- Paul G Crichton
- From the Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Yang Lee
- From the Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Jonathan J Ruprecht
- From the Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Elizabeth Cerson
- From the Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Chancievan Thangaratnarajah
- From the Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Martin S King
- From the Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge CB2 0XY, United Kingdom
| | - Edmund R S Kunji
- From the Mitochondrial Biology Unit, Medical Research Council, Hills Road, Cambridge CB2 0XY, United Kingdom
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Booty LM, King MS, Thangaratnarajah C, Majd H, James AM, Kunji ERS, Murphy MP. The mitochondrial dicarboxylate and 2-oxoglutarate carriers do not transport glutathione. FEBS Lett 2015; 589:621-8. [PMID: 25637873 PMCID: PMC4332691 DOI: 10.1016/j.febslet.2015.01.027] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 01/19/2015] [Accepted: 01/20/2015] [Indexed: 01/23/2023]
Abstract
Glutathione carries out vital protective roles within mitochondria, but is synthesised in the cytosol. Previous studies have suggested that the mitochondrial dicarboxylate and 2-oxoglutarate carriers were responsible for glutathione uptake. We set out to characterise the putative glutathione transport by using fused membrane vesicles of Lactococcus lactis overexpressing the dicarboxylate and 2-oxoglutarate carriers. Although transport of the canonical substrates could be measured readily, an excess of glutathione did not compete for substrate uptake nor could transport of glutathione be measured directly. Thus these mitochondrial carriers do not transport glutathione and the identity of the mitochondrial glutathione transporter remains unknown.
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Affiliation(s)
- Lee M Booty
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Martin S King
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Chancievan Thangaratnarajah
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Homa Majd
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Andrew M James
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | - Edmund R S Kunji
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK.
| | - Michael P Murphy
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK.
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Podzamczer D, King MS, Klein CE, Flexner C, Katlama C, Havlir DV, Letendre SL, Eron JJ, Brun SC, Bernstein B. High-Dose Lopinavir/Ritonavir in Highly Treatment-Experienced HIV-1 Patients: Efficacy, Safety, and Predictors of Response. HIV Clinical Trials 2015; 8:193-204. [PMID: 17720659 DOI: 10.1310/hct0804-193] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To investigate the efficacy and safety of high-dose lopinavir/ritonavir (LPV/r) therapy in multiple protease inhibitor, non-nucleoside reverse transcriptase inhibitor (NNRTI)-experienced subjects. METHOD Thirty-six HIV-1-infected subjects were randomized to LPV/r 400/300 mg or 667/167 mg bid in a 48-week, open-label study. Subjects also received investigator-selected nucleoside reverse transcriptase inhibitors (NRTIs). Primary outcomes were the proportion of subjects with HIV-1 RNA levels <50 copies/mL at week 24 and time until loss of virologic response through week 48. RESULTS Six of 17 (35%) and 10 of 19 (53%) subjects in the 400/300 and 667/167 groups, respectively, completed 48 weeks of treatment. Median durations of follow-up in discontinued subjects and all subjects were 15 weeks and 32 weeks, respectively. Forty-four percent of subjects achieved HIV-1 RNA <50 copies/mL at least once; 18% (400/300 mg) and 21% (667/167 mg) of subjects achieved HIV-1 RNA <50 copies/mL at week 24 (intent-to-treat analysis). Corresponding results at week 48 were 18% (400/300 mg) and 26% (667/167 mg). No statistically significant differences in adverse event incidence occurred between treatment groups, except for a higher vomiting rate in the 400/300 mg dose group. Predictors of response included baseline LPV inhibitory quotient and number of active NRTIs. CONCLUSION Higher doses of LPV/r may provide substantial antiviral activity in multiple class-experienced subjects.
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Affiliation(s)
- Daniel Podzamczer
- Infectious Disease Service, Hospital Universitari de Bellvitge, Barcelona, Spain
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Rahim S, Fredrick LM, da Silva BA, Bernstein B, King MS. Geographic and Temporal Trends of Transmitted HIV-1 Drug Resistance Among Antiretroviral-Naïve Subjects Screening for Two Clinical Trials in North America and Western Europe. HIV Clinical Trials 2015; 10:94-103. [PMID: 19487179 DOI: 10.1310/hct1002-94] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Qaqish R, van Wyk J, King MS. A comparison of the FDA TLOVR and FDA Snapshot algorithms based on studies evaluating once-daily vs. twice daily lopinavir/ritonavir (LPV/r) regimens. J Int AIDS Soc 2010. [PMCID: PMC3113062 DOI: 10.1186/1758-2652-13-s4-p58] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Roessler MM, King MS, Robinson AJ, Armstrong FA, Harmer J, Hirst J. Direct assignment of EPR spectra to structurally defined iron-sulfur clusters in complex I by double electron-electron resonance. Proc Natl Acad Sci U S A 2010; 107:1930-5. [PMID: 20133838 PMCID: PMC2808219 DOI: 10.1073/pnas.0908050107] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In oxidative phosphorylation, complex I (NADH:quinone oxidoreductase) couples electron transfer to proton translocation across an energy-transducing membrane. Complex I contains a flavin mononucleotide to oxidize NADH, and an unusually long series of iron-sulfur (FeS) clusters, in several subunits, to transfer the electrons to quinone. Understanding coupled electron transfer in complex I requires a detailed knowledge of the properties of individual clusters and of the cluster ensemble, and so it requires the correlation of spectroscopic and structural data: This has proved a challenging task. EPR studies on complex I from Bos taurus have established that EPR signals N1b, N2 and N3 arise, respectively, from the 2Fe cluster in the 75 kDa subunit, and from 4Fe clusters in the PSST and 51 kDa subunits (positions 2, 7, and 1 along the seven-cluster chain extending from the flavin). The other clusters have either evaded detection or definitive signal assignments have not been established. Here, we combine double electron-electron resonance (DEER) spectroscopy on B. taurus complex I with the structure of the hydrophilic domain of Thermus thermophilus complex I. By considering the magnetic moments of the clusters and the orientation selectivity of the DEER experiment explicitly, signal N4 is assigned to the first 4Fe cluster in the TYKY subunit (position 5), and N5 to the all-cysteine ligated 4Fe cluster in the 75 kDa subunit (position 3). The implications of our assignment for the mechanisms of electron transfer and energy transduction by complex I are discussed.
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Affiliation(s)
- Maxie M. Roessler
- Center for Advanced Electron Spin Resonance, and
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom; and
| | - Martin S. King
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Alan J. Robinson
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, United Kingdom
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory, Department of Chemistry, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom; and
| | | | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, Wellcome Trust/Medical Research Council Building, Hills Road, Cambridge, CB2 0XY, United Kingdom
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French MA, King MS, Tschampa JM, da Silva BA, Landay AL. Serum immune activation markers are persistently increased in patients with HIV infection after 6 years of antiretroviral therapy despite suppression of viral replication and reconstitution of CD4+ T cells. J Infect Dis 2009; 200:1212-5. [PMID: 19728788 DOI: 10.1086/605890] [Citation(s) in RCA: 177] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
The effect of long-term antiretroviral therapy on serum immune activation markers was assessed in a cohort of 63 patients before and after 6 years of boosted lopinavir-based antiretroviral therapy. High levels of most markers were associated with lower CD4(+) T cell counts at baseline and at year 6, with the exception of soluble cytotoxic T lymphocyte antigen-4 (sCTLA-4); high levels of sCTLA-4 were associated with higher CD4(+) T cell counts at year 6. Abnormalities of serum immune activation markers persisted after 6 years of ART but probably had different causes. Further investigation of the clinical usefulness of assaying immunoglobulin A, neopterin, and sCTLA-4 levels to assess the effectiveness of treatments for human immunodeficiency virus (HIV) disease are warranted.
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Affiliation(s)
- Martyn A French
- School of Pathology and Laboratory Medicine, University of Western Australia, and Department of Clinical Immunology and Immunogenetics, Royal Perth Hospital and PathWest Laboratory Medicine, Perth, Australia.
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King MS, Sharpley MS, Hirst J. Reduction of hydrophilic ubiquinones by the flavin in mitochondrial NADH:ubiquinone oxidoreductase (Complex I) and production of reactive oxygen species. Biochemistry 2009; 48:2053-62. [PMID: 19220002 PMCID: PMC2651670 DOI: 10.1021/bi802282h] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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NADH:ubiquinone oxidoreductase (complex I) from bovine heart mitochondria is a complicated, energy-transducing, membrane-bound enzyme that contains 45 different subunits, a non-covalently bound flavin mononucleotide, and eight iron−sulfur clusters. The mechanisms of NADH oxidation and intramolecular electron transfer by complex I are gradually being defined, but the mechanism linking ubiquinone reduction to proton translocation remains unknown. Studies of ubiquinone reduction by isolated complex I are problematic because the extremely hydrophobic natural substrate, ubiquinone-10, must be substituted with a relatively hydrophilic analogue (such as ubiquinone-1). Hydrophilic ubiquinones are reduced by an additional, non-energy-transducing pathway (which is insensitive to inhibitors such as rotenone and piericidin A). Here, we show that inhibitor-insensitive ubiquinone reduction occurs by a ping-pong type mechanism, catalyzed by the flavin mononucleotide cofactor in the active site for NADH oxidation. Moreover, semiquinones produced at the flavin site initiate redox cycling reactions with molecular oxygen, producing superoxide radicals and hydrogen peroxide. The ubiquinone reactant is regenerated, so the NADH:Q reaction becomes superstoichiometric. Idebenone, an artificial ubiquinone showing promise in the treatment of Friedreich’s Ataxia, reacts at the flavin site. The factors which determine the balance of reactivity between the two sites of ubiquinone reduction (the energy-transducing site and the flavin site) and the implications for mechanistic studies of ubiquinone reduction by complex I are discussed. Finally, the possibility that the flavin site in complex I catalyzes redox cycling reactions with a wide range of compounds, some of which are important in pharmacology and toxicology, is discussed.
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Affiliation(s)
- Martin S King
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
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Campo RE, Da Silva BA, Cotte L, Gathe JC, Gazzard B, Hicks CB, Klein CE, Chiu YL, King MS, Bernstein BM. Predictors of loss of virologic response in subjects who simplified to lopinavir/ritonavir monotherapy from lopinavir/ritonavir plus zidovudine/lamivudine. AIDS Res Hum Retroviruses 2009; 25:269-75. [PMID: 19292590 DOI: 10.1089/aid.2008.0217] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Previous studies have demonstrated that lopinavir/ritonavir monotherapy maintained plasma HIV-1 RNA suppression in a large proportion of antiretroviral naive subjects. However, more subjects receiving lopinavir/ritonavir monotherapy experienced confirmed virologic rebound >50 copies/ml compared to a standard three-drug HAART regimen. In this study, we sought to determine the factors associated with maintenance of virologic suppression in subjects receiving lopinavir/ritonavir monotherapy. Antiretroviral-naive HIV-1-infected volunteers were randomized 2:1 to initiate a lopinavir/ritonavir-based combination regimen followed by simplification to lopinavir/ritonavir monotherapy or an efavirenz-based triple combination therapy and followed for 96 weeks. Potential predictors of time to loss of virologic response included baseline demographics, baseline HIV-1 RNA levels, baseline CD4(+) T cell counts, adherence as determined by 4-day subject recall, duration of HIV-1 RNA <50 copies/ml prior to simplification, and lopinavir concentrations. By the Cox proportional hazards model, higher reported adherence levels and higher baseline CD4(+) T cell counts were associated with a greater likelihood of maintaining virologic suppression while receiving lopinavir/ritonavir monotherapy. Lopinavir concentrations, including trough concentrations, were not significantly associated with virologic outcomes. This analysis suggests that adherence and higher baseline CD4(+) T cell counts may help to predict who will sustain virologic suppression with lopinavir/ritonavir monotherapy. The data also suggest that measuring lopinavir concentrations is not useful in predicting virologic response in these patients.
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Affiliation(s)
- Rafael E. Campo
- University of Miami School of Medicine, Miami, Florida 33136
| | | | - Laurent Cotte
- Service d'Hépatologie et de SIDA, Hôtel-Dieu, Hospices Civils de Lyon, Lyon, France
| | | | | | | | | | - Yi-Lin Chiu
- Abbott Laboratories, Abbott Park, Illinois 60064
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Cameron DW, da Silva BA, Arribas JR, Myers RA, Bellos NC, Gilmore N, King MS, Bernstein BM, Brun SC, Hanna GJ. A 96-week comparison of lopinavir-ritonavir combination therapy followed by lopinavir-ritonavir monotherapy versus efavirenz combination therapy. J Infect Dis 2008; 198:234-40. [PMID: 18540803 DOI: 10.1086/589622] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Antiretroviral-naive HIV-1-infected volunteers received zidovudine/lamivudine plus either lopinavir/ritonavir (n=104) or efavirenz (n=51). Lopinavir/ritonavir-treated subjects demonstrating 3 consecutive monthly HIV-1 RNA levels <50 copies/mL started lopinavir/ritonavir monotherapy. In previous-failure=failure analysis, 48% (lopinavir/ritonavir) and 61% (efavirenz) maintained HIV-1 RNA at <50 copies/mL through week 96, (P= .17; 95% confidence interval [CI] for the difference, -29% to 4%); in noncompletion=failure analysis, 60% (lopinavir/ritonavir) and 63% (efavirenz) maintained HIV-1 RNA at <50 copies/mL at week 96 (P= .73; 95% CI for the difference, -19% to 13%). Significant sparing of peripheral lipoatrophy was noted in the lopinavir/ritonavir simplification strategy. This study has provided important information for future studies using treatment simplified to lopinavir/ritonavir monotherapy.
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Affiliation(s)
- D William Cameron
- Division of Infectious Diseases, University of Ottawa at The Ottawa Hospital, Ottawa, Ontario, Canada
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Murphy RL, da Silva BA, Hicks CB, Eron JJ, Gulick RM, Thompson MA, McMillan F, King MS, Hanna GJ, Brun SC. Seven-year efficacy of a lopinavir/ritonavir-based regimen in antiretroviral-naïve HIV-1-infected patients. HIV Clin Trials 2008; 9:1-10. [PMID: 18215977 DOI: 10.1310/hct0901-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Evaluate efficacy and tolerability of lopinavir/ritonavir (LPV/r) plus stavudine and lamivudine long term in antiretroviral-naïve patients. DESIGN Open-label follow-up of prospective, randomized, multicenter trial. METHOD Antiretroviral-naïve HIV-infected subjects (N = 00) received of 3 doses of LPV/r plus stavudine and lamivudine for 48 weeks then received LPV/r soft-gel capsules 400/00 mg plus stavudine and lamivudine. After 6 years, subjects replaced stavudine with tenofovir. RESULTS At 7 years, by intent-to-treat analysis, 61 % had plasma HIV-RNA <400 copies/mL and 59% had < 50 copies/mL. Thirty-nine subjects discontinued treatment due to adverse events (n = 6), personal/other reasons (0), loss to follow-up (9), and noncompliance (4). Among 28 subjects qualifying for drug resistance testing, no protease inhibitor or stavudine resistance was observed and 4 showed lamivudine resistance. Most common drug-related moderate or severe adverse events were diarrhea (28%), nausea (6%), and abdominal pain (11 %). Subjects who received stavudine (median 6.6 years) and switched to tenofovir demonstrated significant improvements in total cholesterol (p = .009), triglycerides (p = .023), apolipoprotein C-III (p < .001 ), adiponectin (p = .008), fasting insulin (p = .04), and leptin (p = .03). CONCLUSION LPV/r-based therapy demonstrated sustained efficacy with no protease inhibitor or stavudine resistance through 7 years in antiretroviral-naïve patients. Switching from stavudine to tenofovir resulted in significant improvements in multiple metabolic parameters.
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Esterházy D, King MS, Yakovlev G, Hirst J. Production of reactive oxygen species by complex I (NADH:ubiquinone oxidoreductase) from Escherichia coli and comparison to the enzyme from mitochondria. Biochemistry 2008; 47:3964-71. [PMID: 18307315 DOI: 10.1021/bi702243b] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The generation of reactive oxygen species by mitochondrial complex I (NADH:ubiquinone oxidoreductase) is considered a significant cause of cellular oxidative stress, linked to neuromuscular diseases and aging. Defining its mechanism is important for the formulation of causative connections between complex I defects and pathological effects. Oxygen is probably reduced at two sites in complex I, one associated with NADH oxidation in the mitochondrial matrix and the other associated with ubiquinone reduction in the membrane. Here, we study complex I from Escherichia coli, exploiting similarities and differences in the bacterial and mitochondrial enzymes to extend our knowledge of O2 reduction at the active site for NADH oxidation. E. coli and bovine complex I reduce O2 at essentially the same rate, with the same potential dependence (set by the NAD (+)/NADH ratio), showing that the rate-determining step is conserved. The potential dependent rate of H2O2 production does not correlate to the potential of the distal [2Fe-2S] cluster N1a in E. coli complex I, excluding it as the point of O2 reduction. Therefore, our results confirm previous proposals that O2 reacts with the fully reduced flavin mononucleotide. Assays for superoxide production by E. coli complex I were prone to artifacts, but dihydroethidium reduction showed that, upon reducing O2, it produces approximately 20% superoxide and 80% H2O2. In contrast, bovine complex I produces 95% superoxide. The results are consistent with (but do not prove) a specific role for cluster N1a in determining the outcome of O2 reduction; possible reaction mechanisms are discussed.
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Affiliation(s)
- Daria Esterházy
- Medical Research Council Dunn Human Nutrition Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, United Kingdom
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Molina JM, Podsadecki TJ, Johnson MA, Wilkin A, Domingo P, Myers R, Hairrell JM, Rode RA, King MS, Hanna GJ. A lopinavir/ritonavir-based once-daily regimen results in better compliance and is non-inferior to a twice-daily regimen through 96 weeks. AIDS Res Hum Retroviruses 2007; 23:1505-14. [PMID: 18160008 DOI: 10.1089/aid.2007.0107] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We assessed the safety and efficacy and evaluated the adherence to lopinavir/ritonavir (LPV/r) dosed QD or BID in antiretroviral-naive, HIV-1-infected subjects through 96 weeks of treatment. A randomized, open-label, multicenter comparative study was conducted. A total of 190 antiretroviral-naive subjects with plasma HIV-1 RNA above 1000 copies/ml and any CD4(+) T cell count were enrolled. Subjects were randomized (3:2) to LPV/r 800/200 mg QD (n = 115) or 400/100 mg BID (n = 75). Subjects received TDF 300 mg and FTC 200 mg QD. Adherence to LPV/r through 96 weeks was measured using MEMS((R)) monitors. Median baseline VL and CD4(+) T cell count were 4.8 log(10) copies/ml and 216 cells/mm(3), respectively. Prior to week 96, 37% (QD) and 39% (BID) of subjects discontinued, primarily due either to adverse events (17% QD, 9% BID) or to loss to follow-up or nonadherence (12% QD, 17% BID). The proportion of subjects with VL <50 copies/ml [57% QD, 53% BID; p = 0.582 (ITT NC = F)], change in CD4 count (244 cells/mm(3) QD, 264 cells/mm(3) BID; p = 0.513), and evolution of resistance did not differ between groups through 96 weeks. Diarrhea (17% QD, 5% BID, p = 0.014) was the most common moderate or severe, study drug-related adverse event. Adherence to LPV/r was higher for the QD group than the BID group and declined over time in both groups. Time to loss of virologic response was significantly associated with adherence to LPV/r in both groups. LPV/r QD resulted in virologic response similar to LPV/r BID through 96 weeks in antiretroviral-naive subjects. Adherence was significantly higher in the QD group.
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Simpson KN, Luo MP, Chumney EC, King MS, Brun S. Cost effectiveness of lopinavir/ritonavir compared with atazanavir in antiretroviral-naive patients: modelling the combined effects of HIV and heart disease. Clin Drug Investig 2007; 27:67-74. [PMID: 17177581 DOI: 10.2165/00044011-200727010-00006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
BACKGROUND AND OBJECTIVE The choice of initial highly active antiretroviral therapy (HAART) should take into account the need to balance efficacy, adverse event risk, resistance concerns for the treatment of HIV and treatment costs. Increased risk of coronary heart disease (CHD) may be of special concern in the selection of HAART therapy, because differences in potential CHD risk have been reported for different regimens. This study aimed to estimate the long-term combined effects of HIV disease and antiretroviral (ARV)-related risk for CHD on quality-adjusted survival and healthcare costs for ARV-naive patients. METHODS A previously validated Markov model was updated and supplemented with the Framingham CHD risk equation. In the model, the average patient was male, aged 37 years and had a baseline 10-year CHD risk of 4.6%. Patients started with either lopinavir/ritonavir or unboosted atazanavir as the first protease inhibitor (PI). Clinical trial data were used to estimate the differences between these two therapies. The daily PI costs were $US18.52 for lopinavir/ritonavir and $US22.08 for atazanavir. Other costs were estimated from Medicaid billing databases and average wholesale drug price reports. All model costs were reported as the 2004 present value in US currency. The model's time horizon reflected a patient's lifetime, and the perspective of the analysis was that of the healthcare system and did not include indirect costs in the model cost estimates. Various CHD risk levels were tested in the sensitivity analysis. RESULTS In the base case, the model predicted a median duration of initial PI regimen of 5.6 years for lopinavir/ritonavir and 3.8 years for atazanavir. Over 10 years, patients who started on atazanavir had 30 additional AIDS events per 100 patients. Only 0.7 additional CHD events per 100 patients occurred for those who started on lopinavir/ritonavir. The model estimated 10-year total healthcare cost savings of $US12,543 per patient in the lopinavir/ritonavir group. The lifetime incremental cost effectiveness of lopinavir/ritonavir versus atazanavir was $US6797 per quality-adjusted life-year gained. CONCLUSION Lopinavir/ritonavir is a highly cost-effective regimen relative to atazanavir for the treatment of HIV. The effect of lopinavir/ritonavir on long-term CHD risk was minimal compared with the increased risk of AIDS/death projected for a less efficacious first PI regimen. The cost of lipid-lowering drugs and treatment of CHD for patients taking the lopinavir/ritonavir regimen was only 1.2% of the cost of AIDS care per person, which was too small to have a significant effect on the overall cost savings with lopinavir/ritonavir therapy. Thus, a decision to forgo potency and durability in an ARV regimen for an ARV-naive patient in favour of a less potent regimen with an improved lipid profile may prove to be costly over time, in terms of both budget impact and life expectancy.
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Affiliation(s)
- Kit N Simpson
- Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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Maldarelli F, Palmer S, King MS, Wiegand A, Polis MA, Mican J, Kovacs JA, Davey RT, Rock-Kress D, Dewar R, Liu S, Metcalf JA, Rehm C, Brun SC, Hanna GJ, Kempf DJ, Coffin JM, Mellors JW. ART suppresses plasma HIV-1 RNA to a stable set point predicted by pretherapy viremia. PLoS Pathog 2007; 3:e46. [PMID: 17411338 PMCID: PMC1847689 DOI: 10.1371/journal.ppat.0030046] [Citation(s) in RCA: 275] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Accepted: 02/13/2007] [Indexed: 11/19/2022] Open
Abstract
Current antiretroviral therapy is effective in suppressing but not eliminating HIV-1 infection. Understanding the source of viral persistence is essential for developing strategies to eradicate HIV-1 infection. We therefore investigated the level of plasma HIV-1 RNA in patients with viremia suppressed to less than 50-75 copies/ml on standard protease inhibitor- or non-nucleoside reverse transcriptase inhibitor-containing antiretroviral therapy using a new, real-time PCR-based assay for HIV-1 RNA with a limit of detection of one copy of HIV-1 RNA. Single copy assay results revealed that >80% of patients on initial antiretroviral therapy for 60 wk had persistent viremia of one copy/ml or more with an overall median of 3.1 copies/ml. The level of viremia correlated with pretherapy plasma HIV-1 RNA but not with the specific treatment regimen. Longitudinal studies revealed no significant decline in the level of viremia between 60 and 110 wk of suppressive antiretroviral therapy. These data suggest that the persistent viremia on current antiretroviral therapy is derived, at least in part, from long-lived cells that are infected prior to initiation of therapy.
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Affiliation(s)
- Frank Maldarelli
- HIV Drug Resistance Program, National Cancer Institute, Frederick, Maryland, United States of America.
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King MS, Rode R, Cohen-Codar I, Calvez V, Marcelin AG, Hanna GJ, Kempf DJ. Predictive genotypic algorithm for virologic response to lopinavir-ritonavir in protease inhibitor-experienced patients. Antimicrob Agents Chemother 2007; 51:3067-74. [PMID: 17576846 PMCID: PMC2043245 DOI: 10.1128/aac.00388-07] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Several genotypic resistance algorithms have been proposed for quantitation of the degree of phenotypic resistance to the human immunodeficiency virus (HIV) protease inhibitor (PI) lopinavir (LPV), including the original LPV mutation score. In this study, we retrospectively evaluated 21 codons in HIV protease known to be associated with PI resistance in a large antiretroviral agent-experienced observational patient cohort, "Autorisation Temporaire d'Utilization" (ATU), to assess whether a more optimal algorithm could be derived by using virologic response data from patients treated with LPV in combination with ritonavir (LPV/r). Five of the 11 mutations constituting the LPV mutation score were not associated with a virologic response, while 4 additional mutations not included in this score demonstrated an association. Therefore, the LPV ATU score, which includes mutations at codons 10, 20, 24, 33, 36, 47, 48, 54, 82, and 84, was constructed and shown in two different types of multivariable analyses of the ATU cohort to be a better predictor of the virologic response than the LPV mutation score. The LPV ATU score was also more strongly associated with a virologic response when it was applied to independent clinical trial populations of PI-experienced patients receiving LPV/r. This study provides the basis for a new genotypic resistance algorithm that is useful for predicting the antiviral activities of LPV/r-based regimens in PI-experienced patients. The refined algorithm may be useful in making clinical treatment decisions and in refining genetic and pharmacologic methods for assessing the activity of LPV/r.
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Affiliation(s)
- Martin S King
- Global Pharmaceutical Research and Development, Abbott, 100 Abbott Park Rd., R436 AP9A-2, Abbott Park, IL 60064, USA.
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Cameron DW, Becker S, King MS, da Silva B, Klein C, Tokimoto D, Foit C, Calhoun D, Bernstein B, Hanna GJ. Exploratory study comparing the metabolic toxicities of a lopinavir/ritonavir plus saquinavir dual protease inhibitor regimen versus a lopinavir/ritonavir plus zidovudine/lamivudine nucleoside regimen. J Antimicrob Chemother 2007; 59:957-63. [PMID: 17350990 DOI: 10.1093/jac/dkm029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES To assess the safety, efficacy and metabolic toxicity of lopinavir/ritonavir + saquinavir or zidovudine/lamivudine and evaluate the pharmacokinetics of lopinavir/ritonavir + saquinavir. METHODS HIV-1-infected, antiretroviral-naive subjects were randomized to lopinavir/ritonavir (400/100 mg) twice daily + saquinavir (800 mg) or zidovudine/lamivudine (150/300 mg) in a Phase II, 48 week study. Subjects receiving lopinavir/ritonavir + zidovudine/lamivudine initiated escalating doses of saquinavir (400, 600 and 800 mg) weekly for 3 weeks. RESULTS By intent-to-treat (non-completer = failure) analysis, 10/16 (63%) lopinavir/ritonavir + saquinavir-treated and 7/14 (50%) lopinavir/ritonavir + zidovudine/lamivudine-treated subjects achieved plasma HIV-1 RNA <50 copies/mL (P=0.713) at week 48. Safety, tolerability, metabolic changes and truncal fat increases were similar between groups. Small decreases in the lower extremity fat in the zidovudine/lamivudine group (-6%) and a statistically significant increase in the lower extremity fat in the saquinavir group (+19%) were observed. Lopinavir/ritonavir co-administered with saquinavir 600 or 800 mg twice daily produced saquinavir concentrations similar to those previously reported for saquinavir/ritonavir 1000/100 mg twice daily. CONCLUSIONS Treatment regimens had similar efficacy and tolerability. Metabolic parameters suggested lipoatrophy in the zidovudine/lamivudine treatment group. Saquinavir 600 and 800 mg twice daily produced concentrations similar to those previously reported for saquinavir/ritonavir 1000/100 mg twice daily.
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Affiliation(s)
- D William Cameron
- University of Ottawa at The Ottawa Hospital, Box 228, 501 Smyth Rd., Ottawa, ON, Canada, K1H 8L6
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Landay A, da Silva BA, King MS, Albrecht M, Benson C, Eron J, Glesby M, Gulick R, Hicks C, Kessler H, Murphy R, Thompson M, White AC, Wolfe P, McMillan FI, Hanna GJ. Evidence of ongoing immune reconstitution in subjects with sustained viral suppression following 6 years of lopinavir-ritonavir treatment. Clin Infect Dis 2007; 44:749-54. [PMID: 17278071 DOI: 10.1086/511681] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 11/07/2006] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND We evaluated the immunologic impact of highly active antiretroviral therapy in subjects who maintained human immunodeficiency virus type 1 (HIV-1) suppression through 6 years of receiving a lopinavir-ritonavir-based regimen. METHODS A total of 100 antiretroviral-naive subjects with any CD4+ T cell count initiated therapy with lopinavir-ritonavir, stavudine, and lamivudine. Sixty-three subjects who remained in the study for 6 years were assessed. Laboratory measurements included plasma HIV-1 RNA levels, multiparameter flow cytometry of immune cells, and markers of maturation and activation. RESULTS After 6 years, 62 of 63 subjects had plasma HIV-1 RNA levels <50 copies/mL. The mean increase in CD4+ T cell count was 528 cells/microL (P<.001), and 81% of subjects had CD4+ T cell counts >500 cells/microL, compared with 21% of subjects at baseline. The mean ratio of CD4+ T cell count to CD8+ T cell count increased from 0.38 at baseline to 0.96 at year 6 (P<.001). The percentage of subjects with cell counts below the lower limit of normal at year 6, compared with at baseline, was significantly decreased for total T cells, B cells, and natural killer cells. At year 6, the median CD4+ T cell activation level was 3.4%, and the median CD8+ T cell activation level was 5.8%. CONCLUSIONS The receipt of a lopinavir-ritonavir-based regimen resulted in ongoing immune reconstitution through 6 years of therapy in a cohort of HIV-1-infected, antiretroviral-naive subjects with suppressed HIV-1 RNA levels. Normalization of activation marker expression on CD4+ and CD8+ T cell subsets was demonstrated.
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Affiliation(s)
- Alan Landay
- Dept. of Immunology/Microbiology, Rush University Medical Center, Chicago, IL 60612, USA.
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Johnson MA, Gathe JC, Podzamczer D, Molina JM, Naylor CT, Chiu YL, King MS, Podsadecki TJ, Hanna GJ, Brun SC. A once-daily lopinavir/ritonavir-based regimen provides noninferior antiviral activity compared with a twice-daily regimen. J Acquir Immune Defic Syndr 2006; 43:153-60. [PMID: 16951643 DOI: 10.1097/01.qai.0000242449.67155.1a] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To evaluate the safety and noninferiority and to explore the efficacy of administration of once-daily versus twice-daily lopinavir/ritonavir (LPV/r) in antiretroviral-naive HIV-1-infected subjects. DESIGN Randomized, open-label, multicenter, comparative study. METHODS One hundred ninety antiretroviral-naive subjects with plasma HIV-1 RNA level >1000 copies/mL and any CD4 cell count were randomized to lopinavir/ritonavir at a dose of 800/200 mg administered once daily (n = 115) or lopinavir/ritonavir at a dose of 400/100 mg administered twice daily (n = 75). Subjects also received tenofovir disoproxil fumarate (TDF) at a dose of 300 mg and emtricitabine (FTC) at a dose of 200 mg administered once daily. RESULTS The median baseline plasma HIV-1 RNA level and CD4 count were 4.8 log10 copies/mL and 216 cells/mm, respectively. Before week 48, 20% (once daily) and 29% (twice daily) subjects discontinued. Virologic responses of the subjects through 48 weeks were comparable; 70% (once daily) and 64% (twice daily) achieved an HIV-1 RNA level <50 copies/mL by intent-to-treat, noncompleter = failure analysis. No subject demonstrated LPV or TDF resistance, but 3 subjects (2 in the once-daily group, 1 in the twice-daily group) demonstrated FTC resistance. Mean increases in CD4 count were similar. Diarrhea (16% in the once-daily group, 5% in the twice-daily group; P = 0.036) was the most common moderate or severe study drug-related adverse event. CONCLUSIONS Through 48 weeks, a once-daily regimen of lopinavir/ritonavir + TDF + FTC appears to have similar virologic and immunologic responses in antiretroviral-naive subjects as the same regimen with lopinavir/ritonavir administered twice daily. Both regimens were relatively well tolerated, and no LPV or TDF resistance was observed.
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Bartlett JA, Buda JJ, von Scheele B, Mauskopf JA, Davis EA, Elston R, King MS, Lanier ER. Minimizing resistance consequences after virologic failure on initial combination therapy: a systematic overview. J Acquir Immune Defic Syndr 2006; 41:323-31. [PMID: 16540933 DOI: 10.1097/01.qai.0000197070.69859.f3] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To identify optimal first-line therapies based on the rate of virologic success (VS) and the preservation of future treatment options in antiretroviral therapy (ART)-naive subjects. DESIGN Systematic overview of genotypic resistance mutations from clinical trials of combination ART. METHODS Various sources were searched for studies in ART-naive subjects providing virologic response rates and genotypes from subjects with virologic failure. The International AIDS Society-USA genotypic resistance guidelines were used to calculate regimen resistance cost (RCreg) and number of active drug (AD) scores for each regimen and to rank the regimens. RESULTS Intra- and interstudy comparisons showed higher VS rates for nonnucleoside reverse transcriptase inhibitor (NNRTI) regimens (range: 51%-76%) and boosted protease inhibitor (boosted PI) regimens (range: 55%-79%). Boosted PI failures had the lowest RCreg (range: 0.12-0.21) and the highest AD (range: 19.80-20.18) scores. NNRTI failures had higher RCreg (range: 0.00-1.22) and lower AD (range: 16.83-21) scores. CONCLUSIONS NNRTI and boosted PI regimens provide the highest rates of VS in treatment-naive HIV-infected persons. Treatment option scores were higher in subjects who failed boosted PI- containing regimens versus NNRTI-containing regimens, however.
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Affiliation(s)
- John A Bartlett
- AIDS Research and Treatment Center, Duke University Medical Center, Durham, NC, USA.
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Marcelin AG, Cohen-Codar I, King MS, Colson P, Guillevic E, Descamps D, Lamotte C, Schneider V, Ritter J, Segondy M, Peigue-Lafeuille H, Morand-Joubert L, Schmuck A, Ruffault A, Palmer P, Chaix ML, Mackiewicz V, Brodard V, Izopet J, Cottalorda J, Kohli E, Chauvin JP, Kempf DJ, Peytavin G, Calvez V. Virological and pharmacological parameters predicting the response to lopinavir-ritonavir in heavily protease inhibitor-experienced patients. Antimicrob Agents Chemother 2005; 49:1720-6. [PMID: 15855487 PMCID: PMC1087618 DOI: 10.1128/aac.49.5.1720-1726.2005] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genotypic inhibitory quotient (GIQ) has been proposed as a way to integrate drug exposure and genotypic resistance to protease inhibitors and can be useful to enhance the predictivity of virologic response for boosted protease inhibitors. The aim of this study was to evaluate the predictivity of the GIQ in 116 protease inhibitor-experienced patients treated with lopinavir-ritonavir. The overall decrease in human immunodeficiency virus type 1 (HIV-1) RNA from baseline to month 6 was a median of -1.50 log(10) copies/ml and 40% of patients had plasma HIV-1 RNA below 400 copies/ml at month 6. The overall median lopinavir study-state C(min) concentration was 5,856 ng/ml. Using univariate linear regression analyses, both lopinavir GIQ and the number of baseline lopinavir mutations were highly associated with virologic response through 6 months. In the multivariate analysis, only lopinavir GIQ, baseline HIV RNA, and the number of prior protease inhibitors were significantly associated with response. When the analysis was limited to patients with more highly mutant viruses (three or more lopinavir mutations), only lopinavir GIQ remained significantly associated with virologic response. This study suggests that GIQ could be a better predictor of the virologic response than virological (genotype) or pharmacological (minimal plasma concentration) approaches used separately, especially among patients with at least three protease inhibitor resistance mutations. Therapeutic drug monitoring for patients treated by lopinavir-ritonavir would likely be most useful in patients with substantially resistant viruses.
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Affiliation(s)
- Anne-Geneviève Marcelin
- Department of Virology, Pitié-Salpêtrière Hospital, 83 Boulevard de l'hôpital, 75013 Paris, France.
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King MS, Brun SC, Kempf DJ. Relationship between Adherence and the Development of Resistance in Antiretroviral‐Naive, HIV‐1–Infected Patients Receiving Lopinavir/Ritonavir or Nelfinavir. J Infect Dis 2005; 191:2046-52. [PMID: 15897990 DOI: 10.1086/430387] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2004] [Accepted: 01/31/2005] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Relationships between adherence to protease inhibitor (PI)-based therapy and resistance development have not been fully characterized. METHODS We conducted a double-blind, randomized, controlled study of lopinavir/ritonavir versus nelfinavir, each administered with stavudine and lamivudine, in 653 antiretroviral-naive, human immunodeficiency virus (HIV)-1-infected patients. Relationships between adherence and probability of resistance development were evaluated by local linear regression or logistic regression. RESULTS A higher risk of detectable HIV-1 RNA loads after week 24 was associated with lower adherence (odds ratio [OR], 1.08 per 1% decrease in adherence [95% confidence interval {CI}, 1.05-1.10]; P<.001) and nelfinavir use (OR, 2.4 vs. lopinavir/ritonavir [95% CI, 1.6-3.6]; P<.001). Among all nelfinavir-treated patients, a bell-shaped relationship between adherence and the risk of nelfinavir resistance was observed, with a maximum probability of 20% at 85%-90% adherence. No lopinavir resistance was observed. A bell-shaped relationship was also observed for the probability of lamivudine resistance, with a maximum probability of 50% at 75%-80% adherence to nelfinavir and of 15% at 80%-85% adherence to lopinavir/ritonavir. CONCLUSIONS Bell-shaped relationships between adherence and resistance were observed. Irrespective of adherence level, the risk of detectable HIV-1 RNA loads or of PI or lamivudine resistance was significantly higher in nelfinavir-treated patients than in lopinavir/ritonavir-treated patients.
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Affiliation(s)
- Martin S King
- Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois 60064, USA.
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