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1
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Mitochondrial potassium and chloride channels.

100%
Kicińska A., Dębska G., Kunz W., Szewczyk A.
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2000
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vol. 47
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issue 3
541-551
EN
Channels selective for potassium or chloride ions are present in inner mitochondrial membranes. They probably play an important role in mitochondrial events such as the formation of ΔpH and regulation of mitochondrial volume changes. Mitochondrial potassium and chloride channels could also be the targets for pharmacologically active compounds such as potassium channel openers and antidiabetic sulfonylureas. This review describes the properties, pharmacology, and current observations concerning the functional role of mitochondrial potassium and chloride channels.
2
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Transmembrane segment M2 of glycine receptor as a model system for the pore-forming structure of ion channels.

100%
Bednarczyk P., Szewczyk A., Dołowy K.
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2002
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vol. 49
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issue 4
869-875
EN
The glycine receptor belongs to the ligand-gated ion channel superfamily. It is a chloride conducting channel composed of four transmembrane domains. It was previously shown that the second transmembrane domain (M2) of the glycine receptor forms an ion conduction pathway throught lipid bilayers. The amino-acid sequence of the transmembrane segment M2 of the glycine receptor has a high homology to all receptors of the ligand-gated ion channel superfamily. In our report, we have used a synthetic M2 peptide. It was incorporated into a planar membrane of known lipid composition and currents induced by M2 were measured by the Black Lipid Membrane technique. When the planar lipid bilayer was composed of 75% phosphatidylethanolamine and 25% phosphatidylserine, the reversal potential measured in a 150/600 mM KCl (cis/trans) gradient was -19 mV suggesting that the examined pore was preferential to anions, PK/PCl = 0.25. In contrast, when 75% phosphatidylserine and 25% phosphatidylethanolamine was used, the reversal potential was +20 mV and the pore was preferential to cations, PK/PCl = 4.36. Single-channel currents were recorded with two predominant amplitudes corresponding to the main-conductance and sub-conductance states. Both conductance states (about 12 pS and 30 pS) were measured in a symmetric solution of 50 mM KCl. The observed single-channel properties suggest that the selectivity and conductance of the pore formed by the M2 peptide of the glycine receptor depend on the lipid composition of the planar bilayer.
3
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Intracellular potassium and chloride channels: An update.

100%
Dębska G., Kicińska A., Skalska J., Szewczyk A.
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2001
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vol. 48
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issue 1
137-144
EN
Channels selective for potassium or chloride ions are present in all intracellular membranes such as mitochondrial membranes, sarcoplasmic/endoplasmic reticulum, nuclear membrane and chromaffin granule membranes. They probably play an important role in events such as acidification of intracellular compartments and regulation of organelle volume. Additionally, intracellular ion channels are targets for pharmacologically active compounds, e.g. mitochondrial potassium channels interact with potassium channel openers such as diazoxide. This review describes current observations concerning the properties and functional roles of intracellular potassium and chloride channels.
4
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Benzodiazepine binding to mitochondrial membranes of the amoeba Acanthamoeba castellanii and the yeast Saccharomyces cerevisiae.

100%
Slocinska M., Szewczyk A., Hryniewiecka L., Kmita H.
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vol. 51
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issue 4
953-962
EN
Benzodiazepine binding sites were studied in mitochondria of unicellular eukaryotes, the amoeba Acathamoeba castellanii and the yeast Saccharomyces cerevisiae, and also in rat liver mitochondria as a control. For that purpose we applied Ro5-4864, a well-known ligand of the mitochondrial benzodiazepine receptor (MBR) present in mammalian mitochondria. The levels of specific [3H]Ro5-4864 binding, the dissociation constant (KD) and the number of [3H]Ro5-4864 binding sites (Bmax) determined for fractions of the studied mitochondria indicate the presence of specific [3H]Ro5-4864 binding sites in the outer membrane of yeast and amoeba mitochondria as well as in yeast mitoplasts. Thus, A. castellanii and S. cerevisiae mitochondria, like rat liver mitochondria, contain proteins able to bind specifically [3H]Ro5-4864. Labeling of amoeba, yeast and rat liver mitochondria with [3H]Ro5-4864 revealed proteins identified as the voltage dependent anion selective channel (VDAC) in the outer membrane and adenine nucleotide translocase (ANT) in the inner membrane. Therefore, the specific MBR ligand binding is not confined only to mammalian mitochondria and is more widespread within the eukaryotic world. However, it can not be excluded that MBR ligand binding sites are exploited efficiently only by higher multicellular eukaryotes. Nevertheless, the MBR ligand binding sites in mitochondria of lower eukaryotes can be applied as useful models in studies on mammalian MBR.
5
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Does the energy state of mitochondria influence the surface potential of the inner mitochondrial membrane? A critical appraisal

88%
Wojtczak L., Nałęcz M. J., Famulski K. S., Dygas A., Szewczyk A.
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issue 3
299-318
6
Content available remote

Purification of rat liver mitochondrial anion carriers by triazine dye affinity chromatography

87%
Szewczyk A., Poddana H., Nałęcz M. J.
Acta Biochimica Polonica
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1990
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vol. 37
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issue 1
113-116
7
Content available remote

The ATP-regulated Ki^+ channel in mitochondria: five years after its discovery

86%
Szewczyk A.
Acta Biochimica Polonica
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1996
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vol. 43
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issue 4
713-719
8
Content available remote

ATP-sensitive K^+ channel in mitochondria

63%
Szewczyk A., Mikołajek B., Pikuła S., Nałęcz M.
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vol. 40
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issue 3
329-336
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