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Petrovszki P, Sebők-Nagy K, Páli T. The Activity of Native Vacuolar Proton-ATPase in an Oscillating Electric Field - Demystifying an Apparent Effect of Music on a Biomolecule. Front Mol Biosci 2021; 8:772167. [PMID: 34805280 PMCID: PMC8595334 DOI: 10.3389/fmolb.2021.772167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/21/2021] [Indexed: 11/13/2022] Open
Abstract
The effect of an oscillating electric field generated from music on yeast vacuolar proton-ATPase (V-ATPase) activity in its native environment is reported. An oscillating electric field is generated by electrodes that are immersed into a dispersion of yeast vacuolar membrane vesicles natively hosting a high concentration of active V-ATPase. The substantial difference in the ATP hydrolysing activity of V-ATPase under the most stimulating and inhibiting music is unprecedented. Since the topic, i.e., an effect of music on biomolecules, is very attractive for non-scientific, esoteric mystification, we provide a rational explanation for the observed new phenomenon. Good correlation is found between changes in the specific activity of the enzyme and the combined intensity of certain frequency bands of the Fourier spectra of the music clips. Most prominent identified frequencies are harmonically related to each other and to the estimated rotation rate of the enzyme. These results lead to the conclusion that the oscillating electric field interferes with periodic trans-membrane charge motions in the working enzyme.
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Affiliation(s)
- Pál Petrovszki
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Krisztina Sebők-Nagy
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
| | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Szeged, Hungary
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2
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Harrison MA, Muench SP. The Vacuolar ATPase - A Nano-scale Motor That Drives Cell Biology. Subcell Biochem 2018; 87:409-459. [PMID: 29464568 DOI: 10.1007/978-981-10-7757-9_14] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The vacuolar H+-ATPase (V-ATPase) is a ~1 MDa membrane protein complex that couples the hydrolysis of cytosolic ATP to the transmembrane movement of protons. In essentially all eukaryotic cells, this acid pumping function plays critical roles in the acidification of endosomal/lysosomal compartments and hence in transport, recycling and degradative pathways. It is also important in acid extrusion across the plasma membrane of some cells, contributing to homeostatic control of cytoplasmic pH and maintenance of appropriate extracellular acidity. The complex, assembled from up to 30 individual polypeptides, operates as a molecular motor with rotary mechanics. Historically, structural inferences about the eukaryotic V-ATPase and its subunits have been made by comparison to the structures of bacterial homologues. However, more recently, we have developed a much better understanding of the complete structure of the eukaryotic complex, in particular through advances in cryo-electron microscopy. This chapter explores these recent developments, and examines what they now reveal about the catalytic mechanism of this essential proton pump and how its activity might be regulated in response to cellular signals.
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Affiliation(s)
- Michael A Harrison
- School of Biomedical Sciences, Faculty of Biological Sciences, The University of Leeds, Leeds, UK.
| | - Steven P Muench
- School of Biomedical Sciences, Faculty of Biological Sciences, The University of Leeds, Leeds, UK
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3
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Ferencz CM, Petrovszki P, Dér A, Sebők-Nagy K, Kóta Z, Páli T. Oscillating Electric Field Measures the Rotation Rate in a Native Rotary Enzyme. Sci Rep 2017; 7:45309. [PMID: 28345665 PMCID: PMC5366918 DOI: 10.1038/srep45309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 02/21/2017] [Indexed: 11/09/2022] Open
Abstract
Rotary enzymes are complex, highly challenging biomolecular machines whose biochemical working mechanism involves intersubunit rotation. The true intrinsic rate of rotation of any rotary enzyme is not known in a native, unmodified state. Here we use the effect of an oscillating electric (AC) field on the biochemical activity of a rotary enzyme, the vacuolar proton-ATPase (V-ATPase), to directly measure its mean rate of rotation in its native membrane environment, without any genetic, chemical or mechanical modification of the enzyme, for the first time. The results suggest that a transmembrane AC field is able to synchronise the steps of ion-pumping in individual enzymes via a hold-and-release mechanism, which opens up the possibility of biotechnological exploitation. Our approach is likely to work for other transmembrane ion-transporting assemblies, not only rotary enzymes, to determine intrinsic in situ rates of ion pumping.
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Affiliation(s)
- Csilla-Maria Ferencz
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Pál Petrovszki
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - András Dér
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Krisztina Sebők-Nagy
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Zoltán Kóta
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
| | - Tibor Páli
- Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Temesvári krt. 62, 6726, Szeged, Hungary
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4
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Schneider CM, Li W, Khownium K, Lushington GH, Georg GI. Enantiospecific Synthesis and Cytotoxicity Evaluation of Oximidine II Analogues. ChemMedChem 2016; 11:1600-16. [PMID: 27240557 PMCID: PMC4987132 DOI: 10.1002/cmdc.201600024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/08/2016] [Indexed: 11/20/2022]
Abstract
Analogues of the anticancer natural product oximidine II were prepared and evaluated for cytotoxicity. One analogue of oximidine II that carries a C15 allylic amide side chain as well as two analogues with C15 vinyl sulfone side chains were found to lack cytotoxicity against the cancer cell line SK‐Mel‐5, thereby confirming the necessity of the C15 enamide side chain of oximidine II for cytotoxicity. Four analogues, designed by comparative molecular similarity index analysis (CoMSIA), that feature a less complex macrolactone scaffold were prepared and tested. The two analogues carrying a C15 vinyl sulfone group and the two analogues with a C15 oximidine II enamide side chain showed weak cytotoxicity against the SK‐Mel‐5 cell line and other cell lines, indicating that the designed simplified macrocycles cannot replace the oximidine II macrocycle.
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Affiliation(s)
- Christopher M Schneider
- Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS, 66045, USA
| | - Wei Li
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, 717 Delaware Street SE, Minneapolis, MN, 55414, USA
| | - Kriangsak Khownium
- Department of Medicinal Chemistry, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS, 66045, USA
| | - Gerald H Lushington
- Molecular Graphics & Modeling Laboratory, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS, 66045, USA
| | - Gunda I Georg
- Department of Medicinal Chemistry, Institute for Therapeutics Discovery and Development, University of Minnesota, 717 Delaware Street SE, Minneapolis, MN, 55414, USA.
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5
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Zhu S, Rea SL, Cheng T, Feng HT, Walsh JP, Ratajczak T, Tickner J, Pavlos N, Xu HZ, Xu J. Bafilomycin A1 Attenuates Osteoclast Acidification and Formation, Accompanied by Increased Levels of SQSTM1/p62 Protein. J Cell Biochem 2015; 117:1464-70. [PMID: 27043248 DOI: 10.1002/jcb.25442] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 11/11/2015] [Indexed: 12/14/2022]
Abstract
Vacuolar proton pump H(+)-adenosine triphosphatases (V-ATPases) play an important role in osteoclast function. Further understanding of the cellular and molecular mechanisms of V-ATPase inhibition is vital for the development of anti-resorptive drugs specifically targeting osteoclast V-ATPases. In this study, we observed that bafilomycin A1, a naturally-occurring inhibitor of V-ATPases, increased the protein level of SQSTM1/p62, a known negative regulator of osteoclast formation. Consistently, we found that bafilomycin A1 diminishes the intracellular accumulation of the acidotropic probe lysotracker in osteoclast-like cells; indicative of reduced acidification. Further, bafilomycin A1 inhibits osteoclast formation with attenuation of cell fusion and multi-nucleation of osteoclast-like cells during osteoclast differentiation. Taken together, these data indicate that bafilomycin A1 attenuates osteoclast differentiation in part via increased levels of SQSTM1/p62 protein, providing further mechanistic insight into the effect of V-ATPase inhibition in osteoclasts.
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Affiliation(s)
- Sipin Zhu
- Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China.,School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
| | - Sarah L Rea
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and UWA Centre for Medical Research, The University of Western Australia, Crawley, WA, 6009, Australia.,Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia
| | - Taksum Cheng
- School of Surgery, Centre of Orthopaedic Research, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Hao Tian Feng
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
| | - John P Walsh
- Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, WA, 6009, Australia.,School of Medicine and Pharmacology, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Thomas Ratajczak
- Laboratory for Molecular Endocrinology, Harry Perkins Institute of Medical Research and UWA Centre for Medical Research, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Jennifer Tickner
- School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
| | - Nathan Pavlos
- School of Surgery, Centre of Orthopaedic Research, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Hua-Zi Xu
- Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China
| | - Jiake Xu
- Department of Orthopaedics, The Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, 325035, China.,School of Pathology and Laboratory Medicine, The University of Western Australia, Crawley, WA, Australia
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6
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Yoshida M, Ishida Y, Adachi K, Murase H, Nakagawa H, Doi T. Solid-Phase Combinatorial Synthesis and Biological Evaluation of Destruxin E Analogues. Chemistry 2015; 21:18417-30. [DOI: 10.1002/chem.201502970] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/17/2015] [Indexed: 11/12/2022]
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7
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Shibata H, Tsuchikawa H, Hayashi T, Matsumori N, Murata M, Usui T. Modification of Bafilomycin Structure to Efficiently Synthesize Solid-State NMR Probes that Selectively Bind to Vacuolar-Type ATPase. Chem Asian J 2015; 10:915-24. [DOI: 10.1002/asia.201403299] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Indexed: 01/05/2023]
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8
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Muench SP, Rawson S, Eyraud V, Delmas AF, Da Silva P, Phillips C, Trinick J, Harrison MA, Gressent F, Huss M. PA1b inhibitor binding to subunits c and e of the vacuolar ATPase reveals its insecticidal mechanism. J Biol Chem 2014; 289:16399-408. [PMID: 24795045 PMCID: PMC4047407 DOI: 10.1074/jbc.m113.541250] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 04/14/2014] [Indexed: 12/03/2022] Open
Abstract
The vacuolar ATPase (V-ATPase) is a 1MDa transmembrane proton pump that operates via a rotary mechanism fuelled by ATP. Essential for eukaryotic cell homeostasis, it plays central roles in bone remodeling and tumor invasiveness, making it a key therapeutic target. Its importance in arthropod physiology also makes it a promising pesticide target. The major challenge in designing lead compounds against the V-ATPase is its ubiquitous nature, such that any therapeutic must be capable of targeting particular isoforms. Here, we have characterized the binding site on the V-ATPase of pea albumin 1b (PA1b), a small cystine knot protein that shows exquisitely selective inhibition of insect V-ATPases. Electron microscopy shows that PA1b binding occurs across a range of equivalent sites on the c ring of the membrane domain. In the presence of Mg·ATP, PA1b localizes to a single site, distant from subunit a, which is predicted to be the interface for other inhibitors. Photoaffinity labeling studies show radiolabeling of subunits c and e. In addition, weevil resistance to PA1b is correlated with bafilomycin resistance, caused by mutation of subunit c. The data indicate a binding site to which both subunits c and e contribute and inhibition that involves locking the c ring rotor to a static subunit e and not subunit a. This has implications for understanding the V-ATPase mechanism and that of inhibitors with therapeutic or pesticidal potential. It also provides the first evidence for the position of subunit e within the complex.
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Affiliation(s)
- Stephen P Muench
- From the School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT Leeds, West Yorkshire, United Kingdom,
| | - Shaun Rawson
- From the School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT Leeds, West Yorkshire, United Kingdom
| | - Vanessa Eyraud
- Institut National de la Recherche Agronomique, Institut National des Sciences Appliquées-Lyon, Université de Lyon, IFR 41, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Batiment Louis-Pasteur 20, avenue Albert Einstein, F-69621 Villeurbanne, France
| | - Agnès F Delmas
- the Centre de Biophysique Moléculaire, Centre National de la Recherche Scientifique Unité Propre de Recherche 4301, Rue Charles Sadron, 45071 Orléans cedex 2, France
| | - Pedro Da Silva
- Institut National de la Recherche Agronomique, Institut National des Sciences Appliquées-Lyon, Université de Lyon, IFR 41, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Batiment Louis-Pasteur 20, avenue Albert Einstein, F-69621 Villeurbanne, France
| | - Clair Phillips
- From the School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT Leeds, West Yorkshire, United Kingdom
| | - John Trinick
- the School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, LS2 9JT Leeds, West Yorkshire, United Kingdom, and
| | - Michael A Harrison
- From the School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, LS2 9JT Leeds, West Yorkshire, United Kingdom
| | - Frédéric Gressent
- Institut National de la Recherche Agronomique, Institut National des Sciences Appliquées-Lyon, Université de Lyon, IFR 41, UMR203 BF2I, Biologie Fonctionnelle Insectes et Interactions, Batiment Louis-Pasteur 20, avenue Albert Einstein, F-69621 Villeurbanne, France
| | - Markus Huss
- Abteilung Tierphysiologie, Fachbereich Biologie/Chemie Universität Osnabrück, 49069 Osnabrück, Germany
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9
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Yoshida M, Sato H, Ishida Y, Nakagawa H, Doi T. Scalable solution-phase synthesis of the biologically active cyclodepsipeptide destruxin E, a potent negative regulator of osteoclast morphology. J Org Chem 2013; 79:296-306. [PMID: 24251640 DOI: 10.1021/jo402437z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The scalable solution-phase synthesis of the cyclodepsipeptide destruxin E (1) has been achieved. Diastereoselective dihydroxylation of the terminal alkene in a 2-alkoxy-4-pentenoic amide, 7, was successfully accomplished utilizing (DHQD)2PHAL as the chiral ligand, and it was found that the use of the l-proline moiety in the substrate as a chiral auxiliary was essential for the induction of high diastereoselectivity to afford the key compound 4 on a gram scale. MNBA-mediated macrolactonization of 3 was also performed without formation of the dimerized product even under higher-dilution conditions, and it is noteworthy that the internal hydrogen bonds and s-cis configuration of the amide bond between N-methylalanine and N-methylvaline in the cyclization precursor 3 would assist in the macrolactonization to provide the macrolactone 2 without forming a dimerized product. Finally, epoxide formation in the side chain afforded destruxin E (1) on a gram scale in high purity (>98%).
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Affiliation(s)
- Masahito Yoshida
- Graduate School of Pharmaceutical Sciences, Tohoku University 6-3 Aza-Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan
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10
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Zhang W, Fortman JL, Carlson JC, Yan J, Liu Y, Bai F, Guan W, Jia J, Matainaho T, Sherman DH, Li S. Characterization of the bafilomycin biosynthetic gene cluster from Streptomyces lohii. Chembiochem 2013; 14:301-6. [PMID: 23362147 PMCID: PMC3771327 DOI: 10.1002/cbic.201200743] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Indexed: 11/08/2022]
Abstract
New hope for old bones: The plecomacrolide bafilomycin has been explored for decades as an anti-osteoporotic. However, its structural complexity has limited the synthesis of analogues. The cloning of the bafilomycin biosynthetic gene cluster from the environmental isolate Streptomyces lohii opens the door to the production of new analogues through bioengineering.
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Affiliation(s)
- Wei Zhang
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao, Shandong 266101 (P. R. China), Fax: (+86)-532-8066-2778
| | - J. L. Fortman
- Life Sciences Institute, Departments of Medicinal Chemistry, Chemistry, and Microbiology and Immunology University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA), Fax: (+1)-734-615-3641
| | - Jacob C. Carlson
- Life Sciences Institute, Departments of Medicinal Chemistry, Chemistry, and Microbiology and Immunology University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA), Fax: (+1)-734-615-3641
| | - Jiyong Yan
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao, Shandong 266101 (P. R. China), Fax: (+86)-532-8066-2778
| | - Yi Liu
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao, Shandong 266101 (P. R. China), Fax: (+86)-532-8066-2778
| | - Fali Bai
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao, Shandong 266101 (P. R. China), Fax: (+86)-532-8066-2778
| | - Wenna Guan
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao, Shandong 266101 (P. R. China), Fax: (+86)-532-8066-2778
| | - Junyong Jia
- Life Sciences Institute, Departments of Medicinal Chemistry, Chemistry, and Microbiology and Immunology University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA), Fax: (+1)-734-615-3641
| | - Teatulohi Matainaho
- Professor Teatulohi Matainaho, Department of Pharmacology, University of Papua New Guinea, Port Morseby (Papua New Guinea)
| | - David H. Sherman
- Life Sciences Institute, Departments of Medicinal Chemistry, Chemistry, and Microbiology and Immunology University of Michigan, 210 Washtenaw Avenue, Ann Arbor, MI 48109-2216 (USA), Fax: (+1)-734-615-3641
| | - Shengying Li
- Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, 189 Songling Road, Qingdao, Shandong 266101 (P. R. China), Fax: (+86)-532-8066-2778
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11
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Ferencz C, Petrovszki P, Kóta Z, Fodor-Ayaydin E, Haracska L, Bóta A, Varga Z, Dér A, Marsh D, Páli T. Estimating the rotation rate in the vacuolar proton-ATPase in native yeast vacuolar membranes. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2012; 42:147-58. [PMID: 23160754 DOI: 10.1007/s00249-012-0871-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 10/10/2012] [Accepted: 10/25/2012] [Indexed: 11/25/2022]
Abstract
The rate of rotation of the rotor in the yeast vacuolar proton-ATPase (V-ATPase), relative to the stator or steady parts of the enzyme, is estimated in native vacuolar membrane vesicles from Saccharomyces cerevisiae under standardised conditions. Membrane vesicles are formed spontaneously after exposing purified yeast vacuoles to osmotic shock. The fraction of total ATPase activity originating from the V-ATPase is determined by using the potent and specific inhibitor of the enzyme, concanamycin A. Inorganic phosphate liberated from ATP in the vacuolar membrane vesicle system, during ten min of ATPase activity at 20 °C, is assayed spectrophotometrically for different concanamycin A concentrations. A fit of the quadratic binding equation, assuming a single concanamycin A binding site on a monomeric V-ATPase (our data are incompatible with models assuming multiple binding sites), to the inhibitor titration curve determines the concentration of the enzyme. Combining this with the known ATP/rotation stoichiometry of the V-ATPase and the assayed concentration of inorganic phosphate liberated by the V-ATPase, leads to an average rate of ~10 Hz for full 360° rotation (and a range of 6-32 Hz, considering the ± standard deviation of the enzyme concentration), which, from the time-dependence of the activity, extrapolates to ~14 Hz (8-48 Hz) at the beginning of the reaction. These are lower-limit estimates. To our knowledge, this is the first report of the rotation rate in a V-ATPase that is not subjected to genetic or chemical modification and is not fixed to a solid support; instead it is functioning in its native membrane environment.
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Affiliation(s)
- Csilla Ferencz
- Institute of Biophysics, Biological Research Centre, Temesvári krt. 62, 6726, Szeged, Hungary
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12
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Proteomic analysis of the mice hippocampus after preconditioning induced by N-methyl-D-aspartate (NMDA). J Mol Neurosci 2012; 50:154-64. [PMID: 23001814 DOI: 10.1007/s12031-012-9888-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 09/11/2012] [Indexed: 12/19/2022]
Abstract
Preconditioning induced by N-methyl-D-aspartate (NMDA) has been used as a therapeutic tool against later neuronal insults. NMDA preconditioning affords neuroprotection against convulsions and cellular damage induced by the NMDA receptor agonist, quinolinic acid (QA) with time-window dependence. This study aimed to evaluate the molecular alterations promoted by NMDA and to compare these alterations in different periods of time that are related to the presence or lack of neuroprotection. Putative mechanisms related to NMDA preconditioning were evaluated via a proteomic analysis by using a time-window study. After a subconvulsant and protective dose of NMDA administration mice, hippocampi were removed (1, 24 or 72 h) and total protein analyzed by 2DE gels and identified by MALDI-TOF. Differential protein expression among the time induction of NMDA preconditioning was observed. In the hippocampus of protected mice (24 h), four proteins: HSP70(B), aspartyl-tRNA synthetase, phosphatidylethanolamine binding protein and creatine kinase were found to be up-regulated. Two other proteins, HSP70(A) and V-type proton ATPase were found down-regulated. Proteomic analysis showed that the neuroprotection induced by NMDA preconditioning altered signaling pathways, cell energy maintenance and protein synthesis and processing. These events may occur in a sense to attenuate the excitotoxicity process during the activation of neuroprotection promoted by NMDA preconditioning.
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13
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Kleinbeck F, Fettes GJ, Fader LD, Carreira EM. Total Synthesis of Bafilomycin A1. Chemistry 2012; 18:3598-610. [DOI: 10.1002/chem.201102797] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Indexed: 11/06/2022]
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14
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Yokomakura A, Hong J, Ohuchi K, Oh SE, Lee JY, Mano N, Takahashi T, Hwang GW, Naganuma A. Increased production of reactive oxygen species by the vacuolar-type (H +)-ATPase inhibitors bafilomycin A1 and concanamycin A in RAW 264 cells. J Toxicol Sci 2012; 37:1045-8. [DOI: 10.2131/jts.37.1045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Aya Yokomakura
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
- Department of Pharmaceutical Sciences, Tohoku University Hospital
| | | | | | - Seong-Eun Oh
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Jin-Yong Lee
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
- Laboratory of Pharmaceutical Health Sciences, School of Pharmacy, Aichi Gakuin University
| | - Nariyasu Mano
- Department of Pharmaceutical Sciences, Tohoku University Hospital
| | - Tsutomu Takahashi
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Gi-Wook Hwang
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
| | - Akira Naganuma
- Laboratory of Molecular and Biochemical Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku University
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15
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Ma B, Xiang Y, An L. Structural bases of physiological functions and roles of the vacuolar H(+)-ATPase. Cell Signal 2011; 23:1244-56. [PMID: 21397012 DOI: 10.1016/j.cellsig.2011.03.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 03/03/2011] [Indexed: 12/09/2022]
Abstract
Vacuolar-type H(+)-ATPases (V-ATPases) is a large multi-protein complex containing at least 14 different subunits, in which subunits A, B, C, D, E, F, G, and H compose the peripheral 500-kDa V(1) responsible for ATP hydrolysis, and subunits a, c, c', c″, and d assembly the 250-kDa membrane-integral V(0) harboring the rotary mechanism to transport protons across the membrane. The assembly of V-ATPases requires the presence of all V(1) and V(0) subunits, in which the V(1) must be completely assembled prior to association with the V(0), accordingly the V(0) failing to assemble cannot provide a membrane anchor for the V(1), thereby prohibiting membrane association of the V-ATPase subunits. The V-ATPase mediates acidification of intracellular compartments and regulates diverse critical physiological processes of cell for functions of its numerous functional subunits. The core catalytic mechanism of the V-ATPase is a rotational catalytic mechanism. The V-ATPase holoenzyme activity is regulated by the reversible assembly/disassembly of the V(1) and V(0), the targeting and recycling of V-ATPase-containing vesicles to and from the plasma membrane, the coupling ratio between ATP hydrolysis and proton pumping, ATP, Ca(2+), and its inhibitors and activators.
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Affiliation(s)
- Binyun Ma
- Key Laboratory of Arid and Grassland Agroecology of Ministry of Education, School of Life Sciences, Lanzhou University, 730000, Lanzhou, China
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16
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Araújo MVF, Mendes VC, Chattopadhyay P, Davies JE. Low-temperature particulate calcium phosphates for bone regeneration. Clin Oral Implants Res 2010; 21:632-41. [DOI: 10.1111/j.1600-0501.2009.01864.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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17
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Weissman KJ, Müller R. Myxobacterial secondary metabolites: bioactivities and modes-of-action. Nat Prod Rep 2010; 27:1276-95. [DOI: 10.1039/c001260m] [Citation(s) in RCA: 225] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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18
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Kawatani M, Osada H. Osteoclast-targeting small molecules for the treatment of neoplastic bone metastases. Cancer Sci 2009; 100:1999-2005. [PMID: 19673888 PMCID: PMC11159880 DOI: 10.1111/j.1349-7006.2009.01294.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Revised: 07/10/2009] [Accepted: 07/10/2009] [Indexed: 11/29/2022] Open
Abstract
Osteoclasts are highly specialized cells that resorb bone, and their abnormal activity is implicated in a variety of human bone diseases. In neoplastic bone metastasis, the bone destruction caused by osteoclasts is not only associated with the formation and progression of metastatic lesions, but also could contribute to frequent complications such as severe pain and pathological fractures, which greatly diminish the quality of life of patients. Bisphosphonates, potent antiresorptive drugs, have been shown to have efficacy for treating bone metastases in many types of cancer, and the development of various molecularly targeted agents is currently proceeding. Thus, inhibition of osteoclast function is now established as an important treatment strategy for bony metastases. This review focuses on promising small molecules that disrupt osteoclast function and introduces our chemical/biological approach for identifying osteoclast-targeting small molecular inhibitors.
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Affiliation(s)
- Makoto Kawatani
- Antibiotics Laboratory, Chemical Biology Department, Advanced Science Institute, RIKEN, Wako-shi, Saitama, Japan
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19
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Synthesis of C18–C28 ketone fragment of micromonospolide B possessing 1,3-diene and 1,3-anti-diol functionalities. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.tetasy.2009.07.042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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20
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Affiliation(s)
- Florian Kleinbeck
- Laboratorium für Organische Chemie, ETH Zürich, HCI H335, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland
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21
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Lebreton S, Jaunbergs J, Roth MG, Ferguson DA, De Brabander JK. Evaluating the potential of vacuolar ATPase inhibitors as anticancer agents and multigram synthesis of the potent salicylihalamide analog saliphenylhalamide. Bioorg Med Chem Lett 2008; 18:5879-83. [PMID: 18657422 DOI: 10.1016/j.bmcl.2008.07.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Revised: 06/26/2008] [Accepted: 07/01/2008] [Indexed: 12/27/2022]
Abstract
The natural product salicylihalamide is a potent inhibitor of the Vacuolar ATPase (V-ATPase), a potential target for antitumor chemotherapy. We generated salicylihalamide-resistant tumor cell lines typified by an overexpansion of lysosomal organelles. We also found that many tumor cell lines upregulate tissue-specific plasmalemmal V-ATPases, and hypothesize that tumors that derive their energy from glycolysis rely on these isoforms to maintain a neutral cytosolic pH. To further validate the potential of V-ATPase inhibitors as leads for cancer chemotherapy, we developed a multigram synthesis of the potent salicylihalamide analog saliphenylhalamide.
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Affiliation(s)
- Sylvain Lebreton
- Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd., Dallas, TX 75390-9038, USA
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23
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Capodicasa E, Cornacchione P, Natalini B, Bartoli A, Coaccioli S, Marconi P, Scaringi L. Omeprazole Induces Apoptosis in Normal Human Polymorphonuclear Leucocytes. Int J Immunopathol Pharmacol 2008; 21:73-85. [DOI: 10.1177/039463200802100109] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
We investigated in vitro apoptosis in human polymorphonuclear neutrophils (PMN) induced by omeprazole. This drug, both in the native (OM) and acidified (OM-HCl) form, is a potent inducer of PMN apoptosis. The effect is time- and dose-dependent. OM-HCl is more efficient than OM in inducing PMN apoptosis. In fact, after 24 h incubation in vitro at 1×10 −4M OM-HCl induces apoptosis in 70% of the cell population compared to 37% induced by OM. Apoptosis induced by both forms of the drug is caspase dependent being significantly reduced by pretreating cells with the caspase 3 inhibitor (DEVDH-CHO). However, some differences in the apoptosis mechanisms between the two forms of the drug seem to exist because PMN treatment with the specific caspase 8 inhibitor (Z-IETD-FMK) only blocks OM-HCl mediated apoptosis. We observed cleavage of caspase 8 only in the cells incubated with OM-HCl while the executioner caspase 3 was activated with both forms of the drug. Furthermore, pretreatment with GM-CSF, a known activator of intracellular survival pathways in PMN, partially protected cells from OM-HCl induced apoptosis but did not contrast the apoptotic effect of OM. Cysteine cathepsin proteases also seem involved in the apoptotic mechanism of both drug forms since the specific inhibitor E64d gave a significant protection. To verify if OM-HCl induced apoptosis was dependent on the sulfenamide bound with the cell sulfhydryl groups we used molecules with thiol groups such as β-mercaptoethanol (β-ME) and reduced glutathione (GSH). Reactions of OM-HCl with cellular sulfhydryl groups are strongly involved in both the triggering and evolving phase of the apoptotic mechanism since significant protection from apoptosis was obtained when PMN were pretreated for 1h with β-ME (lipid-permeable) or GSH (lipid-impermeable). These results show that OM and OM-HCl induce apoptosis in human PMN and suggest that the second binds the sulfhydryl groups, present on the cell membrane, to then penetrate the cell thus causing a further significant increase in apoptosis. OM-induced PMN apoptosis during the treatment of gastric inflammatory disease could be an advantage for the resolution of the phlogosis state. However, this aspect should be further elucidated to assess the optimal therapeutical regimen for gastric diseases which are related to infective agents.
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Affiliation(s)
| | - P. Cornacchione
- General Pathology and Immunology Section, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy
| | - B. Natalini
- Department of Chemistry and Technology of Drugs, University of Perugia, Perugia, Italy
| | - A. Bartoli
- General Pathology and Immunology Section, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy
| | - S. Coaccioli
- Medical Clinic, S. Maria Hospital, Didactic and Scientific Division of Terni, University of Perugia, Perugia, Italy
| | - P. Marconi
- General Pathology and Immunology Section, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy
- Medical Clinic, S. Maria Hospital, Didactic and Scientific Division of Terni, University of Perugia, Perugia, Italy
| | - L. Scaringi
- General Pathology and Immunology Section, Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy
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24
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Yao G, Feng H, Cai Y, Qi W, Kong K. Characterization of vacuolar-ATPase and selective inhibition of vacuolar-H(+)-ATPase in osteoclasts. Biochem Biophys Res Commun 2007; 357:821-7. [PMID: 17462591 DOI: 10.1016/j.bbrc.2007.04.082] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 04/07/2007] [Indexed: 02/05/2023]
Abstract
V-ATPase plays important roles in controlling the extra- and intra-cellular pH in eukaryotic cell, which is most crucial for cellular processes. V-ATPases are composed of a peripheral V(1) domain responsible for ATP hydrolysis and integral V(0) domain responsible for proton translocation. Osteoclasts are multinucleated cells responsible for bone resorption and relate to many common lytic bone disorders such as osteoporosis, bone aseptic loosening, and tumor-induced bone loss. This review summarizes the structure and function of V-ATPase and its subunit, the role of V-ATPase subunits in osteoclast function, V-ATPase inhibitors for osteoclast function, and highlights the importance of V-ATPase as a potential prime target for anti-resorptive agents.
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Affiliation(s)
- GuanFeng Yao
- Department of Orthopedics, The Second Affiliated Hospital, ShanTou University Medical College, ShanTou, GuangDong 515041, China
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25
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Dixon N, Wong LS, Geerlings TH, Micklefield J. Cellular targets of natural products. Nat Prod Rep 2007; 24:1288-310. [DOI: 10.1039/b616808f] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Hong J, Yokomakura A, Nakano Y, Ishihara K, Kaneda M, Onodera M, Nakahama KI, Morita I, Niikura K, Ahn JW, Zee O, Ohuchi K. Inhibition of vacuolar-type (H+)-ATPase by the cytostatic macrolide apicularen A and its role in apicularen A-induced apoptosis in RAW 264.7 cells. FEBS Lett 2006; 580:2723-30. [PMID: 16647709 DOI: 10.1016/j.febslet.2006.04.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2006] [Revised: 03/31/2006] [Accepted: 04/04/2006] [Indexed: 11/27/2022]
Abstract
Apicularen A and the known vacuolar-type (H(+))-ATPase (V-ATPase) inhibitor bafilomycin A(1) induced apoptosis of RAW 264.7 cells, while apicularen B, an N-acetyl-glucosamine glycoside of apicularen A, was far less effective. Apicularen A inhibited vital staining with acridine orange of the intracellular organelles of RAW 264.7 cells, inhibited the ATP-dependent proton transport into inside-out microsome vesicles, and inhibited the bafilomycin A(1)-sensitive ATP hydrolysis. The IC(50) values of the proton transport were 0.58 nM for apicularen A, 13 nM for apicularen B, and 0.95 nM for bafilomycin A(1). Furthermore, apicularen A inhibited the bafilomycin A(1)-sensitive ATP hydrolysis more potently than apicularen B. F-ATPase and P-ATPase were not inhibited by apicularen A. We concluded that apicularen A inhibits V-ATPase, and thus induces apoptosis in RAW 264.7 cells.
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Affiliation(s)
- JangJa Hong
- Laboratory of Pathophysiological Biochemistry, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba Aramaki, Sendai, Miyagi 980-8578, Japan
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27
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Lebreton S, Xie XS, Ferguson D, De Brabander JK. Ring-closing metathesis: a powerful tool for the synthesis of simplified salicylihalamide-based V-ATPase inhibitors. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.06.146] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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Deaton DN, Kumar S. Cathepsin K Inhibitors: Their Potential as Anti-Osteoporosis Agents. PROGRESS IN MEDICINAL CHEMISTRY 2004; 42:245-375. [PMID: 15003723 DOI: 10.1016/s0079-6468(04)42006-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Affiliation(s)
- David N Deaton
- Medicinal Chemistry Department, GlaxoSmithKline Inc., 5 Moore Drive, Research Triangle Park, NC 27709, USA
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30
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Yang K, Blackman B, Diederich W, Flaherty PT, Mossman CJ, Roy S, Ahn YM, Georg GI. Formal Total Synthesis of (+)-Salicylihalamides A and B: A Combined Chiral Pool and RCM Strategy. J Org Chem 2003; 68:10030-9. [PMID: 14682697 DOI: 10.1021/jo0301550] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The formal total synthesis of the (+)-salicylihalamides A and B is detailed, utilizing a chiral pool approach to generate the three stereogenic centers and a ring-closing metathesis (RCM) for the formation of the macrocyclic ring structure. Starting from a known glucose-derived alcohol, the formal total synthesis was achieved in an efficient 13-step protocol in 26% overall yield. It was found that substitution at the remote phenolic group significantly influenced the ratio of the E- and Z-double bond products in the RCM step. The introduction of phenol protecting groups provided E-isomers preferentially and also enhanced the rates of the RCM reactions.
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Affiliation(s)
- KyoungLang Yang
- Department of Medicinal Chemistry, Center for Cancer Experimental Therapeutics, and the Drug Discovery Program, Higuchi Biosciences Center, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, Kansas 66045-7582, USA
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31
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Bowman EJ, Gustafson KR, Bowman BJ, Boyd MR. Identification of a new chondropsin class of antitumor compound that selectively inhibits V-ATPases. J Biol Chem 2003; 278:44147-52. [PMID: 12944415 DOI: 10.1074/jbc.m306595200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We identify a new naturally occurring class of inhibitor of vacuolar H+-ATPases (V-ATPases) isolated from vacuolar membranes of Neurospora crassa and from chromaffin granule membranes of Bos taurus. To date, the new class includes six chondropsins and poecillastrin A, large polyketide-derived macrolide lactams with 33-37 membered rings. In the National Cancer Institute's 60-cell screen the chondropsin class showed a tumor cell growth inhibitory fingerprint essentially indistinguishable from that of the bafilomycin/concanamycin and the salicylihalamide/lobatamide classes of well-established V-ATPase inhibitors. Half-maximal inhibition of V-ATPase activity in vitro occurred at 0.04-0.7 microM for the fungal vacuolar V-ATPase and at 0.4 to >10 microM for the chromaffin granule V-ATPase. Thus, the new inhibitors are somewhat less potent than the other two classes, which typically have Ki values of <10 nM for V-ATPases, and the new inhibitors differ from the other two classes in their specificity. The bafilomycin class inhibits all eucaryotic V-ATPases, the salicylihalamide class inhibits mammalian V-ATPases but not fungal V-ATPases, and the new chondropsin class inhibits the N. crassa V-ATPase better than the chromaffin granule V-ATPase. Two mutations in the N. crassa V-ATPase that affect the binding of bafilomycin had small but reproducible effects on the affinity of chondropsins for the V-ATPase, suggesting the possibility of a similar mechanism of inhibition.
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Affiliation(s)
- Emma Jean Bowman
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, California 95064, USA.
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Rzeszutek K, Sarraf F, Davies JE. Proton pump inhibitors control osteoclastic resorption of calcium phosphate implants and stimulate increased local reparative bone growth. J Craniofac Surg 2003; 14:301-7. [PMID: 12826800 DOI: 10.1097/00001665-200305000-00007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Calcium phosphate (CAP) rods and pastes based on dicalcium and tetracalcium phosphate chemistry were modified with a specific osteoclast proton pump inhibitor, Bafilomycin A(1), and implanted in the distal femurs of young male Wistar rats for 7, 10, and 14 days. The extent of osteoclastic resorption of these materials and the amount of regenerative bone formed were qualitatively evaluated. Resorptive activity similar to the remodeling process of natural bone was observed in the controls. In contrast, the resorption of materials containing Bafilomycin A(1) was considerably lower, even though tartrate-resistant acid phosphatase-positive osteoclasts were present at the tissue/material interface. A greater amount of newly formed bone consistently surrounded the CAP rods and pastes containing Bafilomycin A(1) in comparison to the control specimens, which indicated that this reparative bone was not resorbed as quickly as the new bone surrounding the controls. Increased local bone mass around the Bafilomycin A(1)-modified materials resulted from the diffusion of the proton pump inhibitor into the biological tissue at the defect site. Thus, through inhibition of the osteoclast proton pump, Bafilomycin A(1) slowed down not only the resorption of the implant material but also the resorption of the newly formed reparative bone, which resulted in an increased local bone mass.
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Affiliation(s)
- K Rzeszutek
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 4 Taddle Creek Road, Toronto, Ontario M5S 3G9, Canada
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Xu J, Feng HT, Wang C, Yip KHM, Pavlos N, Papadimitriou JM, Wood D, Zheng MH. Effects of Bafilomycin A1: an inhibitor of vacuolar H (+)-ATPases on endocytosis and apoptosis in RAW cells and RAW cell-derived osteoclasts. J Cell Biochem 2003; 88:1256-64. [PMID: 12647307 DOI: 10.1002/jcb.10477] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bafilomycin A1, a specific inhibitor of V-ATPases, is a potent inhibitor of bone resorption, but the underlying mechanisms of its action remain unclear. In this study, we investigated the effect of Bafilomycin A1 on endocytosis and apoptosis in RAW cells and RAW cell-derived osteoclasts. Quantitative analysis by flow cytometry showed that Bafilomycin A1 increased total transferrin levels when RAW cells were exposed to labeled transferrin and decreased the total uptake of Dextran-rhodamine B, both in a dose- and time-dependent fashion, indicating that Bafilomycin influences receptor-mediated and fluid phase endocytosis in these cells. Furthermore, Bafilomycin A1 induced apoptosis of RAW cells in a dose dependent manner as evidenced by Annexin V flow cytometry. The action of Bafilomycin A1 on endocytotic events appeared to be more sensitive and occurred earlier than on its apoptosis inducing effects, suggesting that interrupting of endocytosis might be an early sign of Bafilomycin-mediated osteoclast inhibition. Semi-quantitative RT-PCR analysis showed that the gene transcripts of putative Bafilomycin A1 binding subunit, V-ATPase-subunit a3, were expressed in the preosteoclastic RAW cell line, and up-regulated during RANKL-induced osteoclastogenesis. Osteoclasts treated with Bafilomycin A1 exhibited apoptosis as well as altered cellular localization of Transferrin Alexa 647. Given that endocytosis and apoptosis are important processes during osteoclastic bone resorption, the potent effect of Bafilomycin A1 on endocytosis and apoptosis of osteoclasts and their precursor cells may in part account for Bafilomycin A1 inhibited bone resorption.
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Affiliation(s)
- Jiake Xu
- Department of Surgery (Orthopaedics), University of Western Australia, QEII Medical Center, Nedlands WA.
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Bowman BJ, Bowman EJ. Mutations in subunit C of the vacuolar ATPase confer resistance to bafilomycin and identify a conserved antibiotic binding site. J Biol Chem 2002; 277:3965-72. [PMID: 11724795 DOI: 10.1074/jbc.m109756200] [Citation(s) in RCA: 118] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bafilomycin A1, a potent inhibitor of vacuolar H(+)-ATPases (V-ATPase), inhibited growth of Neurospora crassa in medium adjusted to alkaline pH. Ninety-eight mutant strains were selected for growth on medium (pH 7.2) containing 0.3 or 1.0 microm bafilomycin. Three criteria suggested that 11 mutant strains were altered in the V-ATPase: 1) these strains accumulated high amounts of arginine when grown at pH 5.8 in the presence of bafilomycin, 2) the mutation mapped to the locus of vma-3, which encodes the proteolipid subunit c of the V-ATPase, and 3) V-ATPase activity in purified vacuolar membranes was resistant to bafilomycin. Sequencing of the genomic DNA encoding vma-3 identified the following mutations: T32I (two strains), F136L (two strains), Y143H (two strains), and Y143N (five strains). Characterization of V-ATPase activity in the four kinds of mutant strains showed that the enzyme was resistant to bafilomycin in vitro, with half-maximal inhibition obtained at 80-400 nm compared with 6.3 nm for the wild-type enzyme. Surprisingly, the mutant enzymes showed only weak resistance to concanamycin. Interestingly, the positions of two mutations corresponded to positions of oligomycin-resistant mutations in the c subunit of F(1)F(0)-ATP synthases (F-ATPases), suggesting that bafilomycin and oligomycin utilize a similar binding site and mechanism of inhibition in the related F- and V-ATPases.
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Affiliation(s)
- Barry J Bowman
- Department of Molecular, University of California, Santa Cruz, California 95064, USA.
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35
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Youmans SJ, Barry CR. BAFILOMYCIN A1 AT NANOMOLAR CONCENTRATIONS SATURABLY INHIBITS A PORTION OF TURTLE BLADDER ACIDIFICATION CURRENT. J Exp Biol 2001; 204:2911-9. [PMID: 11683444 DOI: 10.1242/jeb.204.16.2911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
An earlier report indicated that acid secretion in turtle urinary bladder is driven by an unusual vacuolar H+-ATPase and that the ATPase accounts for essentially all acid secreted. These results, however, are difficult to reconcile with the acid transporters currently ascribed to the renal collecting duct. Here, we re-examine the effect of bafilomycin A1, an inhibitor of vacuolar (V-type) H+-ATPases, on acid secretion by intact isolated bladders from Pseudemys scriptaturtles. Serosal-side bafilomycin had no effect on the transepithelial acidification current (AC). In the mucosal solution, bafilomycin inhibited the AC, with inhibition developing over the range 0.1-10 nmol l-1, with a sigmoidal dose—response curve, and an IC50 of 0.47 nmol l-1. At saturation, approximately 70 % of H+ secretion was inhibited. The remaining 30 % could be abolished by 30 μmol l-1 Sch-28080, which is a level that in other systems is known to inhibit H+/K+-ATPase transport activity specifically and essentially completely. When the order of addition was reversed (Sch-28080 first), there was no change in the magnitude of the effect produced by either inhibitor, and the two together again eliminated the AC. The data indicate that baseline acid secretion in intact bladders is due (i) in part to a highly bafilomycin-sensitive process, with sensitivity typical of vacuolar H+ ATPases; and (ii) in part to a more bafilomycin-resistant process that is sensitive to Sch-28080.
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Affiliation(s)
- S J Youmans
- Department of Physiology, New York College of Osteopathic Medicine, New York Institute of Technology, Long Island 11568-8000, USA.
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Abstract
The strength and integrity of our bones depends on maintaining a delicate balance between bone resorption by osteoclasts and bone formation by osteoblasts. As we age or as a result of disease, this delicate balancing act becomes tipped in favor of osteoclasts so that bone resorption exceeds bone formation, rendering bones brittle and prone to fracture. A better understanding of the biology of osteoclasts and osteoblasts is providing opportunities for developing therapeutics to treat diseases of bone. Drugs that inhibit the formation or activity of osteoclasts are valuable for treating osteoporosis, Paget's disease, and inflammation of bone associated with rheumatoid arthritis or periodontal disease. Far less attention has been paid to promoting bone formation with, for example, growth factors or hormones, an approach that would be a valuable adjunct therapy for patients receiving inhibitors of bone resorption.
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Affiliation(s)
- G A Rodan
- Merck Research Laboratories, West Point, PA 19486, USA. St. Vincent's Institute of Medical Research, Melbourne 3065, Australia.
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37
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Baldwin SA, Mackey JR, Cass CE, Young JD. Nucleoside transporters: molecular biology and implications for therapeutic development. MOLECULAR MEDICINE TODAY 1999; 5:216-24. [PMID: 10322314 DOI: 10.1016/s1357-4310(99)01459-8] [Citation(s) in RCA: 263] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The uptake of nucleosides (or nucleobases) is essential for nucleic acid synthesis in many human cell types and in parasitic organisms that cannot synthesize nucleotides de novo. The transporters responsible are also the route of entry for many cytotoxic nucleoside analogues used in cancer and viral chemotherapy. Moreover, by regulating adenosine concentrations in the vicinity of its cell-surface receptors, nucleoside transporters profoundly affect neurotransmission, vascular tone and other processes. The recent molecular characterization of two families of human nucleoside transporters has provided new insights into the mechanisms of natural nucleoside and drug uptake and into future developments of improved therapies.
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Affiliation(s)
- S A Baldwin
- School of Biochemistry and Molecular Biology, University of Leeds, Leeds, UK LS2 9JT.
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