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Krajewska M, Koprowski P. Solubilization, purification, and functional reconstitution of human ROMK potassium channel in copolymer styrene-maleic acid (SMA) nanodiscs. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183555. [PMID: 33444624 DOI: 10.1016/j.bbamem.2021.183555] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/13/2020] [Accepted: 01/04/2021] [Indexed: 12/18/2022]
Abstract
Expression, purification, and functional reconstitution of mammalian ion channels are often challenging. Heterologous expression of mammalian channels in bacteria can be advantageous due to unrelated protein environment and the lack of risk of copurification of endogenous proteins, e.g., accessory channel subunits that can influence the channel activity. Also, direct recording of channel activity could be challenging due to their intracellular localization like in the case of mitochondrial channels. The activity of purified channels can be characterized at the single-molecule level by electrophysiological techniques, such as planar lipid bilayers (PLB). In this work, we describe a simple approach to accomplish PLB recording of the activity of single renal outer medullary potassium channels ROMK expressed in E. coli. We focused on the ROMK2 isoform that is present at low levels in the mitochondria and can be responsible for mitoKATP activity. We screened for the best construct to express the codon-optimized ROMK proteins with a 6xHis tag for protein purification. The strategy involved the use of optimal styrene-maleic acid (SMA) copolymer, which forms so-called polymer nanodiscs, to solubilize and purify ROMK-containing SMA lipid particles (SMALPs), which were amenable for fusion with PLB. Reconstituted ROMK channels exhibited ion selectivity, rectification, and pharmacological properties, which are in agreement with previous work on ROMK channels.
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Affiliation(s)
- Milena Krajewska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Pasteur str. 3, Warsaw 02-093, Poland
| | - Piotr Koprowski
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology PAS, Pasteur str. 3, Warsaw 02-093, Poland.
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2
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Mertens MAS, Sauer DF, Markel U, Schiffels J, Okuda J, Schwaneberg U. Chemoenzymatic cascade for stilbene production from cinnamic acid catalyzed by ferulic acid decarboxylase and an artificial metathease. Catal Sci Technol 2019. [DOI: 10.1039/c9cy01412h] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We report a chemoenzymatic cascade reaction for stilbene production combining decarboxylation and olefin metathesis with efficient removal of metal contamination.
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Affiliation(s)
| | - Daniel F. Sauer
- Institute of Biotechnology
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Ulrich Markel
- Institute of Biotechnology
- RWTH Aachen University
- 52074 Aachen
- Germany
| | | | - Jun Okuda
- Institute of Inorganic Chemistry
- RWTH Aachen University
- 52074 Aachen
- Germany
| | - Ulrich Schwaneberg
- Institute of Biotechnology
- RWTH Aachen University
- 52074 Aachen
- Germany
- DWI-Leibniz Institute for Interactive Materials
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3
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Dolowy K. Calcium phosphate buffer formed in the mitochondrial matrix during preconditioning supports ΔpH formation and ischemic ATP production and prolongs cell survival -A hypothesis. Mitochondrion 2018; 47:210-217. [PMID: 30448366 DOI: 10.1016/j.mito.2018.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 05/06/2018] [Accepted: 11/14/2018] [Indexed: 10/27/2022]
Abstract
Ischemic preconditioning makes cells less sensitive to oxygen deprivation. A similar effect can be achieved by increasing the calcium concentration and applying potassium channel openers. A hypothetical mechanism of preconditioning is presented. In the mitochondrial matrix, there is a calcium hydroxide buffer consisting of a few insoluble calcium phosphate minerals. During ischemia, calcium ions stored in the matrix buffer start to leak out, forming an electric potential difference, while hydroxyl ions remain in the matrix, maintaining its pH and the matrix volume. Preconditioning factors increase the matrix buffer capacity. Production of ATP during ischemia might be the relic of a pre-endosymbiotic past.
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Affiliation(s)
- Krzysztof Dolowy
- Department of Biophysics, Warsaw University of Life Sciences - SGGW, Nowoursynowska 159, Warszawa 02-776, Poland.
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4
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Jaunet-Lahary T, Goupille A, Jacquemin D, Fleury F, Graton J, Laurent AD. A Joint Theoretical and Experimental Study of the Behavior of the DIDS Inhibitor and its Derivatives. Chemphyschem 2016; 17:2434-45. [DOI: 10.1002/cphc.201600107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Titouan Jaunet-Lahary
- Laboratoire CEISAM-UMR CNR 6230; Université de Nantes; 2 Rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
| | - Anaïs Goupille
- Laboratoire CEISAM-UMR CNR 6230; Université de Nantes; 2 Rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
| | - Denis Jacquemin
- Laboratoire CEISAM-UMR CNR 6230; Université de Nantes; 2 Rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
- Institut Universitaire de France; 1, rue Descartes 75005 Paris Cedex 05 France
| | - Fabrice Fleury
- Laboratoire UFIP-UMR CNR 6286; Université de Nantes; 2 Rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
| | - Jérôme Graton
- Laboratoire CEISAM-UMR CNR 6230; Université de Nantes; 2 Rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
| | - Adèle D. Laurent
- Laboratoire CEISAM-UMR CNR 6230; Université de Nantes; 2 Rue de la Houssinière, BP 92208 44322 Nantes Cedex 3 France
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5
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Abstract
The field of mitochondrial ion channels has recently seen substantial progress, including the molecular identification of some of the channels. An integrative approach using genetics, electrophysiology, pharmacology, and cell biology to clarify the roles of these channels has thus become possible. It is by now clear that many of these channels are important for energy supply by the mitochondria and have a major impact on the fate of the entire cell as well. The purpose of this review is to provide an up-to-date overview of the electrophysiological properties, molecular identity, and pathophysiological functions of the mitochondrial ion channels studied so far and to highlight possible therapeutic perspectives based on current information.
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Ashrafpour M, Babaei JF, Saghiri R, Sepehri H, Sharifi H. Modulation of the hepatocyte rough endoplasmic reticulum single chloride channel by nucleotide-Mg2+ interaction. Pflugers Arch 2012; 464:175-82. [PMID: 22684478 DOI: 10.1007/s00424-012-1121-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 05/27/2012] [Accepted: 05/30/2012] [Indexed: 01/07/2023]
Abstract
The effect of nucleotides on single chloride channels derived from rat hepatocyte rough endoplasmic reticulum vesicles incorporated into bilayer lipid membrane was investigated. The single chloride channel currents were measured in 200/50 mmol/l KCl cis/trans solutions. Adding 2.5 mM adenosine triphosphate (ATP) and adenosine diphosphate (ADP) did not influence channel activity. However, MgATP addition inhibited the chloride channels by decreasing the channel open probability (Po) and current amplitude, whereas mixture of Mg(2+) and ADP activated the chloride channel by increasing the Po and unitary current amplitude. According to the results, there is a novel regulation mechanism for rough endoplasmic reticulum (RER) Cl(-) channel activity by intracellular MgATP and mixture of Mg(2+) and ADP that would result in significant inhibition by MgATP and activation by mixture of Mg(2+) and ADP. These modulatory effects of nucleotide-Mg(2+) complexes on chloride channels may be dependent on their chemical structure configuration. It seems that Mg-nucleotide-ion channel interactions are involved to produce a regulatory response for RER chloride channels.
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Affiliation(s)
- M Ashrafpour
- Cellular and Molecular Research Center, Department of Physiology and Pharmacology, Babol University of Medical Sciences, Babol, Iran.
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Terbach N, Shah R, Kelemen R, Klein PS, Gordienko D, Brown NA, Wilkinson CJ, Williams RSB. Identifying an uptake mechanism for the antiepileptic and bipolar disorder treatment valproic acid using the simple biomedical model Dictyostelium. J Cell Sci 2011; 124:2267-76. [PMID: 21652627 DOI: 10.1242/jcs.084285] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Valproic acid (VPA) is the most highly prescribed epilepsy treatment worldwide and is also used to prevent bipolar disorder and migraine. Surprisingly, very little is known about its mechanisms of cellular uptake. Here, we employ a range of cellular, molecular and genetic approaches to characterize VPA uptake using a simple biomedical model, Dictyostelium discoideum. We show that VPA is taken up against an electrochemical gradient in a dose-dependent manner. Transport is protein-mediated, dependent on pH and the proton gradient and shows strong substrate structure specificity. Using a genetic screen, we identified a protein homologous to a mammalian solute carrier family 4 (SLC4) bicarbonate transporter that we show is involved in VPA uptake. Pharmacological and genetic ablation of this protein reduces the uptake of VPA and partially protects against VPA-dependent developmental effects, and extracellular bicarbonate competes for VPA uptake in Dictyostelium. We further show that this uptake mechanism is likely to be conserved in both zebrafish (Danio rerio) and Xenopus laevis model systems. These results implicate, for the first time, an uptake mechanism for VPA through SLC4-catalysed activity.
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Affiliation(s)
- Nicole Terbach
- Centre for Biomedical Sciences, School of Biological Sciences, Royal Holloway University of London, Egham TW200EX, UK
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8
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Kominkova V, Malekova L, Tomaskova Z, Slezak P, Szewczyk A, Ondrias K. Modulation of intracellular chloride channels by ATP and Mg2+. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2010; 1797:1300-12. [PMID: 20206596 DOI: 10.1016/j.bbabio.2010.02.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2009] [Revised: 02/03/2010] [Accepted: 02/26/2010] [Indexed: 12/15/2022]
Abstract
We report the effects of ATP and Mg2+ on the activity of intracellular chloride channels. Mitochondrial and lysosomal membrane vesicles isolated from rat hearts were incorporated into bilayer lipid membranes, and single chloride channel currents were measured. The observed chloride channels (n=112) possessed a wide variation in single channel parameters and sensitivities to ATP. ATP (0.5-2 mmol/l) modulated and/or inhibited the chloride channel activities (n=38/112) in a concentration-dependent manner. The inhibition effect was irreversible (n=5/93) or reversible (n=15/93). The non-hydrolysable ATP analogue AMP-PNP had a similar inhibition effect as ATP, indicating that phosphorylation did not play a role in the ATP inhibition effect. ATP modulated the gating properties of the channels (n=6/93), decreased the channels' open dwell times and increased the gating transition rates. ATP (0.5-2 mmol/l) without the presence of Mg2+ decreased the chloride channel current (n=12/14), whereas Mg2+ significantly reversed the effect (n=4/4). We suggest that ATP-intracellular chloride channel interactions and Mg2+ modulation of these interactions may regulate different physiological and pathological processes.
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Affiliation(s)
- Viera Kominkova
- Institute of Molecular Physiology and Genetics, Centre of Excellence for Cardiovascular Research, Slovak Academy of Sciences, 83334 Bratislava, Slovakia
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9
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Mitochondrial chloride channels - What are they for? FEBS Lett 2010; 584:2085-92. [DOI: 10.1016/j.febslet.2010.01.035] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 01/11/2010] [Accepted: 01/19/2010] [Indexed: 11/21/2022]
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10
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De Marchi U, Szabò I, Cereghetti GM, Hoxha P, Craigen WJ, Zoratti M. A maxi-chloride channel in the inner membrane of mammalian mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:1438-48. [DOI: 10.1016/j.bbabio.2008.08.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 08/01/2008] [Accepted: 08/12/2008] [Indexed: 01/09/2023]
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11
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Matulef K, Howery AE, Tan L, Kobertz WR, Du Bois J, Maduke M. Discovery of potent CLC chloride channel inhibitors. ACS Chem Biol 2008; 3:419-28. [PMID: 18642799 DOI: 10.1021/cb800083a] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Anion-transport proteins are central to all of physiology, for processes ranging from regulating bone-density, muscle excitability, and blood pressure, to facilitating extreme-acid survival of pathogenic bacteria. 4,4-Diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS) has been used as an anion-transport inhibitor for decades. In this study, we demonstrate that polythiourea products derived from DIDS hydrolysis inhibit three different CLC chloride-transport proteins, ClC-ec1, ClC-0, and ClC-Ka, more effectively than DIDS itself. The structures of the five major products were determined by NMR spectroscopy, mass spectrometry, and chemical synthesis. These compounds bind directly to the CLC proteins, as evidenced by the fact that inhibition of ClC-0 occurs only from the intracellular side and inhibition of ClC-Ka is prevented by the point mutation N68D. These polythioureas are the highest affinity inhibitors known for the CLCs and provide a new class of chemical probes for dissecting the molecular mechanisms of chloride transport.
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Affiliation(s)
- Kimberly Matulef
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
| | - Andrew E. Howery
- Department of Chemistry, Stanford University, Stanford, California 94305
| | - Li Tan
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
| | - William R. Kobertz
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - J. Du Bois
- Department of Chemistry, Stanford University, Stanford, California 94305
| | - Merritt Maduke
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California 94305
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12
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Skalska J, Piwońska M, Wyroba E, Surmacz L, Wieczorek R, Koszela-Piotrowska I, Zielińska J, Bednarczyk P, Dołowy K, Wilczynski GM, Szewczyk A, Kunz WS. A novel potassium channel in skeletal muscle mitochondria. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2008; 1777:651-9. [PMID: 18515063 DOI: 10.1016/j.bbabio.2008.05.007] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 05/07/2008] [Accepted: 05/12/2008] [Indexed: 11/30/2022]
Abstract
In this work we provide evidence for the potential presence of a potassium channel in skeletal muscle mitochondria. In isolated rat skeletal muscle mitochondria, Ca(2+) was able to depolarize the mitochondrial inner membrane and stimulate respiration in a strictly potassium-dependent manner. These potassium-specific effects of Ca(2+) were completely abolished by 200 nM charybdotoxin or 50 nM iberiotoxin, which are well-known inhibitors of large conductance, calcium-activated potassium channels (BK(Ca) channel). Furthermore, NS1619, a BK(Ca)-channel opener, mimicked the potassium-specific effects of calcium on respiration and mitochondrial membrane potential. In agreement with these functional data, light and electron microscopy, planar lipid bilayer reconstruction and immunological studies identified the BK(Ca) channel to be preferentially located in the inner mitochondrial membrane of rat skeletal muscle fibers. We propose that activation of mitochondrial K(+) transport by opening of the BK(Ca) channel may be important for myoprotection since the channel opener NS1619 protected the myoblast cell line C2C12 against oxidative injury.
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Affiliation(s)
- Jolanta Skalska
- Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, 3 Pasteur Street, 02-093 Warsaw, Poland
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