Mechanisms Of Ion Channels Voltage Dependency

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Mechanisms Of Ion Channels Voltage Dependency

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Author : Gildas Loussouarn
language : en
Publisher: Frontiers E-books
Release Date :

Mechanisms Of Ion Channels Voltage Dependency written by Gildas Loussouarn and has been published by Frontiers E-books this book supported file pdf, txt, epub, kindle and other format this book has been release on with categories.

Voltage-gated ion channels are transmembrane proteins in which at least one gate is controlled by the transmembrane potential. They are frequently very selectively permeable to sodium (Nav channels), potassium (Kv channels) or calcium (Cav channels) ions. Depending on the channels, opening of the activation gate is triggered by membrane depolarization (Kv, Nav and Cav channels) or hyperpolarization (HCN channels for instance). In addition, in many voltage-gated channels, a so-called inactivation gate is also present. Compared to the activation gate, the latter is oppositely coupled to the potential: In Kv, Nav and Cav channels, upon membrane depolarization, the inactivation gate closes whereas the activation gate opens. Depending on the cell types in which they are expressed and their physiological role, various voltage-dependent channels can be characterized by their conductance, ion selectivity, pharmacology and voltage-sensitivity. These properties are mainly dictated by the amino-acids sequence and structure of the pore forming subunit(s), presence of accessory subunit(s), membrane composition, intra- and extracellular ions concentration. Noteworthy, despite a profound variety of these ion channels characteristics, it seems that most of them obey to the same global, four-fold structure now obtained by several X-ray crystallography experiments. Given the wealth of electrophysiological, biochemical, optical, and structural data regarding ion channels voltage-dependency, we decided to put together in this e-book, up to date reviews describing the molecular details of these complex voltage-gated channels.

Textbook Of Ion Channels Volume I

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Author : Jie Zheng
language : en
Publisher: CRC Press
Release Date : 2023-06-09

Textbook Of Ion Channels Volume I written by Jie Zheng and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-06-09 with Medical categories.

The Textbook of Ion Channels is a set of three volumes providing a wide-ranging reference source on ion channels for students, instructors and researchers. Ion channels are membrane proteins that control the electrical properties of neurons and cardiac cells; mediate the detection and response to sensory stimuli like light, sound, odor, and taste; and regulate the response to physical stimuli like temperature and pressure. In non-excitable tissues, ion channels are instrumental for the regulation of basic salt balance that is critical for homeostasis. Ion channels are located at the surface membrane of cells, giving them the unique ability to communicate with the environment, as well as the membrane of intracellular organelles, allowing them to regulate internal homeostasis. Ion channels are fundamentally important for human health and diseases, and are important targets for pharmaceuticals in mental illness, heart disease, anesthesia, pain and other clinical applications. The modern methods used in their study are powerful and diverse, ranging from single ion-channel measurement techniques to models of ion channel diseases in animals, and human clinical trials for ion channel drugs. Volume I, Part 1 covers fundamental topics such as the basic principles of ion permeation and selectivity, voltage-dependent, ligand-dependent, and mechano-dependent ion channel activation mechanisms, the mechanisms for ion channel desensitization and inactivation, and basic ion channel pharmacology and inhibition. Volume I, Part 2 offers a practical guide of cardinal methods for researching ion channels, including heterologous expression and voltage-clamp and patch-clamp electrophysiology; isolation of native currents using patch clamping; modeling ion channel gating, structures, and its dynamics; crystallography and cryo-electron microscopy; fluorescence and paramagnetic resonance spectroscopy methods; and genetics approaches in model organisms. All three volumes give the reader an introduction to fundamental concepts needed to understand the mechanism of ion channels; a guide to the technical aspects of ion channel research; a modern guide to the properties of major ion channel families; and includes coverage of key examples of regulatory, physiological and disease roles for ion channels.

Molecular Mechanisms Of Voltage Gating In Ion Channels

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Author : Gildas Loussouarn
language : en
Publisher: Frontiers Media SA
Release Date : 2021-11-03

Molecular Mechanisms Of Voltage Gating In Ion Channels written by Gildas Loussouarn and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-11-03 with Science categories.

Structure Function And Modulation Of Neuronal Voltage Gated Ion Channels

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Author : Valentin K. Gribkoff
language : en
Publisher: John Wiley & Sons
Release Date : 2008-12-09

Structure Function And Modulation Of Neuronal Voltage Gated Ion Channels written by Valentin K. Gribkoff and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008-12-09 with Science categories.

This book discusses voltage-gated ion channels and their importance in drug discovery and development. The book includes reviews of the channel genome, the physiological bases of targeting ion channels in disease, the unique technologies developed for ion channel drug discovery, and the increasingly important role of ion channel screening in cardiac risk assessment. It provides an important reference for research scientists and drug discovery companies.

Textbook Of Ion Channels Volume Ii

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Author : Jie Zheng
language : en
Publisher: CRC Press
Release Date : 2023-06-28

Textbook Of Ion Channels Volume Ii written by Jie Zheng and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-06-28 with Science categories.

The Textbook of Ion Channels is a set of three volumes that provides a wide-ranging refer- ence source on ion channels for students, instructors and researchers. Ion channels are membrane proteins that control the electrical properties of neurons and cardiac cells; mediate the detection and response to sensory stimuli like light, sound, odor, and taste; and regulate the response to physical stimuli like temperature and pressure. In non-excit- able tissues, ion channels are instrumental for the regulation of basic salt balance that is critical for homeostasis. Ion channels are located at the surface membrane of cells, giving them the unique ability to communicate with the environment, as well as the membrane of intracellular organelles, allowing them to regulate internal homeostasis. Ion channels are fundamentally important for human health and diseases, and are important targets for pharmaceuticals in mental illness, heart disease, anesthesia, pain and other clinical appli- cations. The modern methods used in their study are powerful and diverse, ranging from single ion-channel measurement techniques to models of ion channel diseases in animals, and human clinical trials for ion channel drugs. Volume II starts with ion channel taxonomy and features coverage of major ion channel families, and describes the physiological role, structural components, gating mechanisms and biophysics, permeation and selectivity, regulation, pharmacology, and roles in dis- ease mechanisms. Channels in this volume include voltage-activated sodium, calcium and potassium channels, inward-rectifier and two-pore domain potassium channels, calcium- activated potassium channels, cyclic nucleotide-gated channels, pacemaker ion channels, chloride channels, ligand-gated receptors activated by acetylcholine, glutamate, 5-HT3, GABA and glycine, acid-sensing channels, P2X receptors, TRP channels, store-operated channels, pressure-activated piezo channels, ryanodine receptors, and proton channels. All three volumes give the reader an introduction to fundamental concepts needed to understand the mechanism of ion channels; a guide to the technical aspects of ion channel research; offer a modern guide to the properties of major ion channel families; and include coverage of key examples of regulatory, physiological and disease roles for ion channels.

Thermodynamics Of Voltage Dependent Gating Of Ion Channels

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Author :
language : en
Publisher:
Release Date : 2015

Thermodynamics Of Voltage Dependent Gating Of Ion Channels written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with categories.

Voltage-gated ion channels (VGICs) constitute an evolutionary diverse family of integral membrane proteins that transport ions across the hydrophobic membrane bilayers, when triggered by changes in membrane potential. This thesis examines the manifestations of the fundamental laws of thermodynamics on this family of proteins to understand how they operate at the molecular level. In the first few Chapters of this thesis, I describe an analytical approach to extract the energetics of voltage-dependent activation of ion channels and use it to determine the interaction energies between residues in the exemplar Shaker KV channel. The approach involves extracting a special parameter, the median voltage of activation (VM) from experimentally measured gating-charge displacement vs voltage (QV) curves. Next, I use this approach to determine the interaction energies between residues comprising an intersubunit gating nexus, which is likely to be crucial for the relay of structural and energetic information, from the voltage-sensors to the pore. Additionally, I describe how these thermodynamic principles can be extended to deconstruct the allosteric linkage pathways between voltage and ligand dependent activation pathways of polymodal allosteric channels. In the final chapter of this thesis, I study the mechanism by which temperature modulates voltage-dependent gating of ion channels. Gating of some members of the VGIC superfamily is exquisitely sensitive to changes in temperature, however we lack an understanding of the molecular mechanisms underlying temperature sensation and modulation of voltage-dependent channel function. I use a heuristic approach to systematically engineer mutations into the relatively temperature insensitive Shaker KV channel to design a temperature modulated voltage-dependent channel. From the characterization of the relative open probability vs voltage curves of over fifty mutants of the channel at two different temperatures, I propose that thermal sensitivity is mediated by state dependent changes in the solvation status of critical residues, which governs CP of channel gating. I also demonstrate that voltage-sensing charges play a crucial although indirect role in governing the effect of temperature on channel gating. These principles could be very useful to deconstruct the temperature sensing mechanisms of natively thermosensitive channels, such as the thermoTRPs and other structurally unrelated channels, such as Anoctamins.

Site And Mechanism Of Action Of Resin Acids On Voltage Gated Ion Channels

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Author : Malin Silverå Ejneby
language : en
Publisher: Linköping University Electronic Press
Release Date : 2018-05-15

Site And Mechanism Of Action Of Resin Acids On Voltage Gated Ion Channels written by Malin Silverå Ejneby and has been published by Linköping University Electronic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-05-15 with Cell membranes categories.

Voltage-gated ion channels are pore-forming membrane proteins that open or close their gates when the voltage across the membrane is changed. They underlie the electrical activity that enables the heart to pump blood and the brain to receive and send signals. Changes in expression, distribution, and functional properties of voltage-gated ion channels can lead to diseases, such as epilepsy, cardiac arrhythmia, and pain-related disorders. Drugs that modulate the function of voltage-gated ion channels control these diseases in some patients, but the existing drugs do not adequately help all patients, and some also have severe side effects. Resin acids are common components of pine resins, with a hydrophobic three-ringed motif and a negatively charged carboxyl group. They open big-conductance Ca2+-activated K+ (BK) channels and voltage-gated potassium (KV) channels. We aimed to characterize the binding site and mechanism of action of resin acids on a KV channel and explore the effect of a resin acid by modifying the position and valence of charge of the carboxyl group. We tested the effect on several voltage-gated ion channels, including two KV channels expressed in Xenopus laevis oocytes and several voltage-gated ion channels expressed in cardiomyocytes. For this endeavour different electrophysiological techniques, ion channels, and cell types were used together with chemical synthesis of about 140 resin-acid derivatives, mathematical models, and computer simulations. We found that resin acids bind between the lipid bilayer and the Shaker KV channel, in the cleft between transmembrane segment S3 and S4, on the extracellular side of the voltage-sensor domain. This is a fundamentally new interaction site for small-molecule compounds that otherwise usually bind to ion channels in pockets surrounded by water. We also showed that the resin acids open the Shaker KV channel via an electrostatic mechanism, exerted on the positively charged voltage sensor S4. The effect of a resin acid increased when the negatively charged carboxyl group (the effector) and the hydrophobic three-ringed motif (anchor in lipid bilayer) were separated by three atoms: longer stalks decreased the effect. The length rule, in combination with modifications of the anchor, was used to design new resin-acid derivatives that open the human M-type (Kv7.2/7.3) channel. A naturally occurring resin acid also reduced the excitability of cardiomyocytes by affecting the voltage-dependence of several voltage-gated ion channels. The major finding was that the resin acid inactivated sodium and calcium channels, while it activated KV channels at more negative membrane voltages. Computer simulations confirmed that the combined effect on different ion channels reduced the excitability of a cardiomyocyte. Finally, the resin acid reversed induced arrhythmic firing of the cardiomyocytes. In conclusion, resin acids are potential drug candidates for diseases such as epilepsy and cardiac arrhythmia: knowing the binding site and mechanism of action can help to fine tune the resin acid to increase the effect, as well as the selectivity.

Biological Membrane Ion Channels

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Author : Shin-Ho Chung
language : en
Publisher: Springer Science & Business Media
Release Date : 2007-11-13

Biological Membrane Ion Channels written by Shin-Ho Chung and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2007-11-13 with Science categories.

This book deals with recent breakthroughs in ion-channel research that have been brought about by the combined effort of experimental biophysicists and computational physicists, who together are beginning to unravel the story of these exquisitely designed biomolecules. With chapters by leading experts, the book is aimed at researchers in nanodevices and biosensors, as well as advanced undergraduate and graduate students in biology and the physical sciences.

Textbook Of Ion Channels

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Author : Jie Zheng
language : en
Publisher: CRC Press
Release Date : 2023-07-06

Textbook Of Ion Channels written by Jie Zheng and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2023-07-06 with Medical categories.

The Textbook of Ion Channels is a set of three volumes providing a wide-ranging reference source on ion channels for students, instructors, and researchers. Ion channels are membrane proteins that control the electrical properties of neurons and cardiac cells, mediate the detection and response to sensory stimuli like light, sound, odor, and taste, and regulate the response to physical stimuli like temperature and pressure. In non-excitable tissues, ion channels are instrumental for the regulation of basic salt balance that is critical for homeostasis. Ion channels are located at the surface membrane of cells, giving them the unique ability to communicate with the environment, as well as the membrane of intracellular organelles, allowing them to regulate internal homeostasis. Ion channels are fundamentally important for human health and diseases, and are important targets for pharmaceuticals in mental illness, heart disease, anesthesia, pain and other clinical applications. The modern methods used in their study are powerful and diverse, ranging from single ion-channel measurement techniques to models of ion channel diseases in animals, and human clinical trials for ion channel drugs. All three volumes give the reader an introduction to fundamental concepts needed to understand the mechanism of ion channels, a guide to the technical aspects of ion channel research, offer a modern guide to the properties of major ion channel families, and include coverage of key examples of regulatory, physiological, and disease roles for ion channels.

Voltage Gated Sodium Channels

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Author : Peter C. Ruben
language : en
Publisher: Springer Science & Business Media
Release Date : 2014-04-15

Voltage Gated Sodium Channels written by Peter C. Ruben and has been published by Springer Science & Business Media this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-04-15 with Medical categories.

A number of techniques to study ion channels have been developed since the electrical basis of excitability was first discovered. Ion channel biophysicists have at their disposal a rich and ever-growing array of instruments and reagents to explore the biophysical and structural basis of sodium channel behavior. Armed with these tools, researchers have made increasingly dramatic discoveries about sodium channels, culminating most recently in crystal structures of voltage-gated sodium channels from bacteria. These structures, along with those from other channels, give unprecedented insight into the structural basis of sodium channel function. This volume of the Handbook of Experimental Pharmacology will explore sodium channels from the perspectives of their biophysical behavior, their structure, the drugs and toxins with which they are known to interact, acquired and inherited diseases that affect sodium channels and the techniques with which their biophysical and structural properties are studied.