The Experts below are selected from a list of 92412 Experts worldwide ranked by ideXlab platform
Hsiao-ping H. Moore - One of the best experts on this subject based on the ideXlab platform.
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ph of tgn and recycling endosomes of h k atpase transfected HEK 293 Cells implications for ph regulation in the secretory pathway
American Journal of Physiology-cell Physiology, 2003Co-Authors: Terry E. Machen, Mary Jae Leigh, C. Taylor, Tohru Kimura, Shinji Asano, Hsiao-ping H. MooreAbstract:The influences of the gastric H+/K+ pump on organelle pH during trafficking to and from the plasma membrane were investigated using HEK-293 Cells stably expressing the α- and β-subunits of human H+...
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pH of TGN and recycling endosomes of H+/K+-ATPase-transfected HEK-293 Cells: implications for pH regulation in the secretory pathway.
American journal of physiology. Cell physiology, 2003Co-Authors: Terry E. Machen, Mary Jae Leigh, C. Taylor, Tohru Kimura, Shinji Asano, Hsiao-ping H. MooreAbstract:The influences of the gastric H+/K+ pump on organelle pH during trafficking to and from the plasma membrane were investigated using HEK-293 Cells stably expressing the α- and β-subunits of human H+...
Geany Tseng - One of the best experts on this subject based on the ideXlab platform.
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characterization of recombinant human cardiac kcnq1 kcne1 channels i ks stably expressed in HEK 293 Cells
The Journal of Membrane Biology, 2006Co-Authors: Mingqing Dong, Geany Tseng, Guirong LiAbstract:The present study was designed to characterize pharmacological, biophysical and electrophysiological properties of the recombinant human cardiac IKs (KCNQ1/KCNE1) channels at physiological temperature. Human cardiac KCNQ1 and KCNE1 genes were cotransfected into HEK 293 Cells, and a cell clone stably expressing both genes was selected. Membrane currents were recorded using a perforated patch-clamp technique. The typical IKs was slowly activated upon depolarization voltages in HEK 293 Cells stably expressing human cardiac KCNQ1 and KCNE1 genes, and the current was inhibited by IKs blockers HMR 1556 and chromanol 293B, with 50% inhibitory concentrations (IC50s) of 83.8 nM and 9.2 μM, respectively. IKs showed a significant temperature-dependent increase in its magnitude upon elevating bath temperature to 36°C from room temperature (21°C). The current was upregulated by the β-adrenoceptor agonist isoproterenol, and the effect was reversed by H89. In addition, IKs was inhibited by Ba2+ in a concentration-dependent manner (IC50 = 1.4 mM). Action potential clamp revealed a “bell-shaped” time course of IKs during the action potential, and maximal peak current was seen at the plateau of the action potential. A significant use- and frequency-dependent increase of IKs was observed during a train of action potential clamp. These results indicate that the recombinant human cardiac IKs stably expressed in HEK 293 Cells is similar to native IKs in drug sensitivity and regulated by Ba2+ and β-adrenoceptor via the cyclic adenosine monophosphate/protein kinase A pathway. Importantly, the current exhibits significant temperature dependence, a bell-shaped time course during action potential and prominent use- or frequency-dependent accumulation during a train of action potentials.
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Characterization of Recombinant Human Cardiac KCNQ1/KCNE1 Channels ( I Ks ) Stably Expressed in HEK 293 Cells
The Journal of membrane biology, 2006Co-Authors: Mingqing Dong, Chu-pak Lau, Zhan Gao, Geany TsengAbstract:The present study was designed to characterize pharmacological, biophysical and electrophysiological properties of the recombinant human cardiac IKs (KCNQ1/KCNE1) channels at physiological temperature. Human cardiac KCNQ1 and KCNE1 genes were cotransfected into HEK 293 Cells, and a cell clone stably expressing both genes was selected. Membrane currents were recorded using a perforated patch-clamp technique. The typical IKs was slowly activated upon depolarization voltages in HEK 293 Cells stably expressing human cardiac KCNQ1 and KCNE1 genes, and the current was inhibited by IKs blockers HMR 1556 and chromanol 293B, with 50% inhibitory concentrations (IC50s) of 83.8 nM and 9.2 μM, respectively. IKs showed a significant temperature-dependent increase in its magnitude upon elevating bath temperature to 36°C from room temperature (21°C). The current was upregulated by the β-adrenoceptor agonist isoproterenol, and the effect was reversed by H89. In addition, IKs was inhibited by Ba2+ in a concentration-dependent manner (IC50 = 1.4 mM). Action potential clamp revealed a “bell-shaped” time course of IKs during the action potential, and maximal peak current was seen at the plateau of the action potential. A significant use- and frequency-dependent increase of IKs was observed during a train of action potential clamp. These results indicate that the recombinant human cardiac IKs stably expressed in HEK 293 Cells is similar to native IKs in drug sensitivity and regulated by Ba2+ and β-adrenoceptor via the cyclic adenosine monophosphate/protein kinase A pathway. Importantly, the current exhibits significant temperature dependence, a bell-shaped time course during action potential and prominent use- or frequency-dependent accumulation during a train of action potentials.
Mingqing Dong - One of the best experts on this subject based on the ideXlab platform.
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characterization of recombinant human cardiac kcnq1 kcne1 channels i ks stably expressed in HEK 293 Cells
The Journal of Membrane Biology, 2006Co-Authors: Mingqing Dong, Geany Tseng, Guirong LiAbstract:The present study was designed to characterize pharmacological, biophysical and electrophysiological properties of the recombinant human cardiac IKs (KCNQ1/KCNE1) channels at physiological temperature. Human cardiac KCNQ1 and KCNE1 genes were cotransfected into HEK 293 Cells, and a cell clone stably expressing both genes was selected. Membrane currents were recorded using a perforated patch-clamp technique. The typical IKs was slowly activated upon depolarization voltages in HEK 293 Cells stably expressing human cardiac KCNQ1 and KCNE1 genes, and the current was inhibited by IKs blockers HMR 1556 and chromanol 293B, with 50% inhibitory concentrations (IC50s) of 83.8 nM and 9.2 μM, respectively. IKs showed a significant temperature-dependent increase in its magnitude upon elevating bath temperature to 36°C from room temperature (21°C). The current was upregulated by the β-adrenoceptor agonist isoproterenol, and the effect was reversed by H89. In addition, IKs was inhibited by Ba2+ in a concentration-dependent manner (IC50 = 1.4 mM). Action potential clamp revealed a “bell-shaped” time course of IKs during the action potential, and maximal peak current was seen at the plateau of the action potential. A significant use- and frequency-dependent increase of IKs was observed during a train of action potential clamp. These results indicate that the recombinant human cardiac IKs stably expressed in HEK 293 Cells is similar to native IKs in drug sensitivity and regulated by Ba2+ and β-adrenoceptor via the cyclic adenosine monophosphate/protein kinase A pathway. Importantly, the current exhibits significant temperature dependence, a bell-shaped time course during action potential and prominent use- or frequency-dependent accumulation during a train of action potentials.
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Characterization of Recombinant Human Cardiac KCNQ1/KCNE1 Channels ( I Ks ) Stably Expressed in HEK 293 Cells
The Journal of membrane biology, 2006Co-Authors: Mingqing Dong, Chu-pak Lau, Zhan Gao, Geany TsengAbstract:The present study was designed to characterize pharmacological, biophysical and electrophysiological properties of the recombinant human cardiac IKs (KCNQ1/KCNE1) channels at physiological temperature. Human cardiac KCNQ1 and KCNE1 genes were cotransfected into HEK 293 Cells, and a cell clone stably expressing both genes was selected. Membrane currents were recorded using a perforated patch-clamp technique. The typical IKs was slowly activated upon depolarization voltages in HEK 293 Cells stably expressing human cardiac KCNQ1 and KCNE1 genes, and the current was inhibited by IKs blockers HMR 1556 and chromanol 293B, with 50% inhibitory concentrations (IC50s) of 83.8 nM and 9.2 μM, respectively. IKs showed a significant temperature-dependent increase in its magnitude upon elevating bath temperature to 36°C from room temperature (21°C). The current was upregulated by the β-adrenoceptor agonist isoproterenol, and the effect was reversed by H89. In addition, IKs was inhibited by Ba2+ in a concentration-dependent manner (IC50 = 1.4 mM). Action potential clamp revealed a “bell-shaped” time course of IKs during the action potential, and maximal peak current was seen at the plateau of the action potential. A significant use- and frequency-dependent increase of IKs was observed during a train of action potential clamp. These results indicate that the recombinant human cardiac IKs stably expressed in HEK 293 Cells is similar to native IKs in drug sensitivity and regulated by Ba2+ and β-adrenoceptor via the cyclic adenosine monophosphate/protein kinase A pathway. Importantly, the current exhibits significant temperature dependence, a bell-shaped time course during action potential and prominent use- or frequency-dependent accumulation during a train of action potentials.
Marco Conti - One of the best experts on this subject based on the ideXlab platform.
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Cellular mechanisms underlying prostaglandin-induced transient cAMP signals near the plasma membrane of HEK-293 Cells.
American Journal of Physiology - Cell Physiology, 2007Co-Authors: Thomas Rich, Wenkuan Xin, Céline Méhats, Jeffrey W. Karpen, Kathryn Hassell, Leslie Piggott, Marco ContiAbstract:We have previously used cyclic nucleotide-gated (CNG) channels as sensors to measure cAMP signals in human embryonic kidney (HEK)-293 Cells. We found that prostaglandin E(1) (PGE(1)) triggered transient increases in cAMP concentration near the plasma membrane, whereas total cAMP levels rose to a steady plateau over the same time course. In addition, we presented evidence that the decline in the near-membrane cAMP levels was due primarily to a PGE(1)-induced stimulation of phosphodiesterase (PDE) activity, and that the differences between near-membrane and total cAMP levels were largely due to diffusional barriers and differential PDE activity. Here, we examine the mechanisms regulating transient, near-membrane cAMP signals. We observed that 5-min stimulation of HEK-293 Cells with prostaglandins triggered a two- to threefold increase in PDE4 activity. Extracellular application of H89 (a PKA inhibitor) inhibited stimulation of PDE4 activity. Similarly, when we used CNG channels to monitor cAMP signals we found that both extracellular and intracellular (via the whole-cell patch pipette) application of H89, or the highly selective PKA inhibitor, PKI, prevented the decline in prostaglandin-induced responses. Following pretreatment with rolipram (a PDE4 inhibitor), H89 had little or no effect on near-membrane or total cAMP levels. Furthermore, disrupting the subcellular localization of PKA with the A-kinase anchoring protein (AKAP) disruptor Ht31 prevented the decline in the transient response. Based on these data we developed a plausible kinetic model that describes prostaglandin-induced cAMP signals. This model has allowed us to quantitatively demonstrate the importance of PKA-mediated stimulation of PDE4 activity in shaping near-membrane cAMP signals.
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Cellular mechanisms underlying prostaglandin-induced transient cAMP signals near the plasma membrane of HEK-293 Cells.
American journal of physiology. Cell physiology, 2006Co-Authors: Thomas C. Rich, Wenkuan Xin, Céline Méhats, Kathryn A. Hassell, Leslie A. Piggott, Jeffrey W. Karpen, Marco ContiAbstract:We have previously used cyclic nucleotide-gated (CNG) channels as sensors to measure cAMP signals in human embryonic kidney (HEK)-293 Cells. We found that prostaglandin E1 (PGE1) triggered transien...
Zbigniew Madeja - One of the best experts on this subject based on the ideXlab platform.
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The inhibitory effect of diphenyltin on gap junctional intercellular communication in HEK-293 Cells is reduced by thioredoxin reductase 1.
Toxicology letters, 2008Co-Authors: Jolanta Sroka, Jarosław Czyz, Marta Wojewoda, Zbigniew MadejaAbstract:Organotins display high biological activity and are toxic to animals and humans. Besides carcinogenic effects, they have been shown to have highly immunotoxic and/or neurotoxic activity; however, the molecular mechanism of their toxicity is not fully understood. The ability of chemicals to inhibit communication via gap junctions has been associated with their toxicological properties. The aim of this study was to determine whether diphenyltin (DPhT) affects the gap junctional intercellular communication (GJIC) and whether thioredoxin reductase (TrxR1) is involved in the regulation of this process. We found that DPhT inhibits GJIC in HEK-293 Cells. The inhibition of GJIC depends on the activation of PKC delta and is associated with the induction of Cx43 phosphorylation at Ser262. Moreover, we found that GJIC inhibited by DPhT in HEK-293 Cells is fully re-established as a result of TrxR1 overexpression.
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The inhibitory effect of diphenyltin on gap junctional intercellular communication in HEK-293 Cells is reduced by thioredoxin reductase 1.
Toxicology Letters, 2008Co-Authors: Jolanta Sroka, Marta Wojewoda, Jarosław Czyż, Zbigniew MadejaAbstract:Abstract Organotins display high biological activity and are toxic to animals and humans. Besides carcinogenic effects, they have been shown to have highly immunotoxic and/or neurotoxic activity; however, the molecular mechanism of their toxicity is not fully understood. The ability of chemicals to inhibit communication via gap junctions has been associated with their toxicological properties. The aim of this study was to determine whether diphenyltin (DPhT) affects the gap junctional intercellular communication (GJIC) and whether thioredoxin reductase (TrxR1) is involved in the regulation of this process. We found that DPhT inhibits GJIC in HEK-293 Cells. The inhibition of GJIC depends on the activation of PKC δ and is associated with the induction of Cx43 phosphorylation at Ser262. Moreover, we found that GJIC inhibited by DPhT in HEK-293 Cells is fully re-established as a result of TrxR1 overexpression.