Regulation of ion channel structure and function by reactive oxygen-nitrogen species

Ion channels subserve diverse cellular functions. Reactive oxygen and nitrogen species modulate ion channel function by a number of mechanisms including 1) transcriptional regulation of gene expression, 2) posttranslational modifications of channel proteins, i.e. nitrosylation, nitration, and oxidation of key amino acid residues, 3) by altering the gain in other signaling pathways that may in turn lead to changes in channel activity or channel gene expression, and 4) by modulating trafficking or turnover of channel proteins, as typified by oxygen radical activation of NF-kB, with subsequent changes in proteasomal degradation of channel degradation. Regardless of the mechanism, as was discussed in a symposium at the 2003 Experimental Biology Meeting in San Diego, CA, changes in the cellular level of reactive oxygen and nitrogen species can have profound effects on the activity of ion channels and cellular function.

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Ion channels and disease

Oxford Textbook of Medicine ◽

10.1093/med/9780198746690.003.0032 ◽

2020 ◽

pp. 246-255

Author(s):

Frances Ashcroft ◽

Paolo Tammaro

Keyword(s):

Ion Channels ◽

Ion Channel ◽

Single Channel ◽

Cell Types ◽

Channel Structure ◽

Channel Proteins ◽

Channel Function ◽

Ion Channel Proteins ◽

Single Channel Currents ◽

Channel Currents

Ion channels are membrane proteins that act as gated pathways for the movement of ions across cell membranes. They are found in both surface and intracellular membranes and play essential roles in the physiology of all cell types. An ever-increasing number of human diseases are now known to be caused by defects in ion channel function. To understand how ion channel defects give rise to disease, it is helpful to understand how the ion channel proteins work. This chapter therefore considers what is known of ion channel structure, explains the properties of the single ion channel, and shows how single-channel currents give rise to action potentials and synaptic potentials.

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Precise control of ion channel and gap junction expression is required for patterning of the regenerating axolotl limb

The International Journal of Developmental Biology ◽

10.1387/ijdb.200114jw ◽

2020 ◽

Vol 64 (10-11-12) ◽

pp. 485-494

Author(s):

Konstantinos Sousounis ◽

Burcu Erdogan ◽

Michael Levin ◽

Jessica L. Whited

Keyword(s):

Ion Channels ◽

Gap Junctions ◽

Ion Channel ◽

Gap Junction ◽

Regulation Of Gene Expression ◽

Transcriptional Networks ◽

Channel Proteins ◽

Junction Protein ◽

Ion Channel Proteins ◽

Voltage Gradients

Axolotls and other salamanders have the capacity to regenerate lost tissue after an amputation or injury. Growth and morphogenesis are coordinated within cell groups in many contexts by the interplay of transcriptional networks and biophysical properties such as ion flows and voltage gradients. It is not, however, known whether regulators of a cell’s ionic state are involved in limb patterning at later stages of regeneration. Here we manipulated expression and activities of ion channels and gap junctions in vivo, in axolotl limb blastema cells. Limb amputations followed by retroviral infections were performed to drive expression of a human gap junction protein Connexin 26 (Cx26), potassium (Kir2.1-Y242F and Kv1.5) and sodium (NeoNav1.5) ion channel proteins along with EGFP control. Skeletal preparation revealed that overexpressing Cx26 caused syndactyly, while overexpression of ion channel proteins resulted in digit loss and structural abnormalities compared to EGFP expressing control limbs. Additionally, we showed that exposing limbs to the gap junction inhibitor lindane during the regeneration process caused digit loss. Our data reveal that manipulating native ion channel and gap junction function in blastema cells results in patterning defects involving the number and structure of the regenerated digits. Gap junctions and ion channels have been shown to mediate ion flows that control the endogenous voltage gradients which are tightly associated with the regulation of gene expression, cell cycle progression, migration, and other cellular behaviors. Therefore, we postulate that mis-expression of these channels may have disturbed this regulation causing uncoordinated cell behavior which results in morphological defects.

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Regulation of gene expression in the nervous system by reactive oxygen and nitrogen species

Metabolic Brain Disease ◽

10.1007/bf02674732 ◽

1997 ◽

Vol 12 (2) ◽

pp. 97-112 ◽

Cited By ~ 11

Author(s):

Jean E. Merrill ◽

Sean P. Murphy

Keyword(s):

Gene Expression ◽

Nervous System ◽

Regulation Of Gene Expression ◽

Reactive Oxygen ◽

Nitrogen Species

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Computational Ion Channel Research: from the Application of Artificial Intelligence to Molecular Dynamics Simulations.

Cellular Physiology and Biochemistry ◽

10.33594/000000336 ◽

2020 ◽

Vol 55 (S3) ◽

pp. 14-45

Keyword(s):

Artificial Intelligence ◽

Molecular Dynamics ◽

Ion Channels ◽

Ion Channel ◽

Computational Methods ◽

Homology Modelling ◽

Channel Structure ◽

Learning Approaches ◽

Qsar Analysis ◽

Wide Range

Although ion channels are crucial in many physiological processes and constitute an important class of drug targets, much is still unclear about their function and possible malfunctions that lead to diseases. In recent years, computational methods have evolved into important and invaluable approaches for studying ion channels and their functions. This is mainly due to their demanding mechanism of action where a static picture of an ion channel structure is often insufficient to fully understand the underlying mechanism. Therefore, the use of computational methods is as important as chemical-biological based experimental methods for a better understanding of ion channels. This review provides an overview on a variety of computational methods and software specific to the field of ion-channels. Artificial intelligence (or more precisely machine learning) approaches are applied for the sequence-based prediction of ion channel family, or topology of the transmembrane region. In case sufficient data on ion channel modulators is available, these methods can also be applied for quantitative structureactivity relationship (QSAR) analysis. Molecular dynamics (MD) simulations combined with computational molecular design methods such as docking can be used for analysing the function of ion channels including ion conductance, different conformational states, binding sites and ligand interactions, and the influence of mutations on their function. In the absence of a three-dimensional protein structure, homology modelling can be applied to create a model of your ion channel structure of interest. Besides highlighting a wide range of successful applications, we will also provide a basic introduction to the most important computational methods and discuss best practices to get a rough idea of possible applications and risks.

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Synthetic Peptide Fragments as Probes for Structure Determination of Potassium Ion-Channel Proteins

Bioscience Reports ◽

10.1023/a:1020257215577 ◽

1998 ◽

Vol 18 (6) ◽

pp. 299-312 ◽

Cited By ~ 6

Author(s):

Parvez I. Haris

Keyword(s):

Potassium Channels ◽

Ion Channel ◽

Potassium Channel ◽

Synthetic Peptide ◽

Potassium Ion ◽

Channel Structure ◽

Phospholipid Membranes ◽

Peptide Fragments ◽

2D Nmr Spectroscopy ◽

Channel Proteins

Potassium channels are a diverse class of transmembrane proteins that are responsible for diffusion of potassium ion across cell membranes. The lack of large quantities of these proteins from natural sources, is a major hindrance in their structural characterization using biophysical techniques. Synthetic peptide fragments corresponding to functionally important domains of these proteins provide an attractive approach towards characterizing the structural organization of these ion-channels. Conformational properties of peptides from three different potassium channels (Shaker, ROMK1 and minK) have been characterized in aqueous media, organic solvents and in phospholipid membranes. Techniques used for these studies include FTIR, CD and 2D-NMR spectroscopy. FTIR spectroscopy has been a particularly valuable tool for characterizing the folding of the ion-channel peptides in phospholipid membranes; the three different types of potassium channels all share a common transmembrane folding pattern that is composed of a predominantly α-helical structure. There is no evidence to suggest the presence of any significant β-sheet structure. These results are in excellent agreement with the crystal structure of a bacterial potassium channel (Doyle, D. A. et al. (1998) Science280:69–77), and suggest that all potassium channel proteins may share a common folding motif where the ion-channel structure is constructed entirely from α-helices.

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WHAT CAUSES ION CHANNEL PROTEINS TO FLUCTUATE OPEN AND CLOSED?

International Journal of Neural Systems ◽

10.1142/s0129065796000282 ◽

1996 ◽

Vol 07 (04) ◽

pp. 321-331 ◽

Cited By ~ 10

Author(s):

LARRY S. LIEBOVITCH ◽

ANGELO T. TODOROV

Keyword(s):

Ion Channels ◽

Patch Clamp ◽

Ion Channel ◽

Patch Clamp Technique ◽

Sodium Potassium ◽

Random Event ◽

Channel Protein ◽

Channel Proteins ◽

Ion Channel Proteins ◽

Open States

Ion channels in the cell membrane spontaneously switch from states that are closed to the flow of ions such as sodium, potassium, and chloride to states that are open to the flow of these ions. The durations of times that an individual ion channel protein spends in the closed and open states can be measured by the patch clamp technique. We explore two basic issues about the molecular properties of ion channels: 1) If the switching between the closed and open state is an inherently random event, what does the patch clamp data tell us about the structure or motions in the ion channel protein? 2) Is this switching random?

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Fluorescence Microscopy of Piezo1 in Droplet Hydrogel Bilayers

10.1101/508176 ◽

2018 ◽

Author(s):

Oskar B. Jaggers ◽

Pietro Ridone ◽

Boris Martinac ◽

Matthew A. B. Baker

Keyword(s):

Ion Channels ◽

Ion Channel ◽

Simultaneous Recording ◽

Mechanical Stimuli ◽

Channel Activity ◽

Channel Proteins ◽

Mechanosensitive Ion Channel ◽

Lymphatic Dysplasia ◽

Hydrogel Bilayer

AbstractMechanosensitive ion channels are membrane gated pores which are activated by mechanical stimuli. The focus of this study is on Piezo1, a newly discovered, large, mammalian, mechanosensitive ion channel, which has been linked to diseases such as dehydrated hereditary stomatocytosis (Xerocytosis) and lymphatic dysplasia. Here we utilize an established in-vitro artificial bilayer system to interrogate single Piezo1 channel activity. The droplet-hydrogel bilayer (DHB) system uniquely allows the simultaneous recording of electrical activity and fluorescence imaging of labelled protein. We successfully reconstituted fluorescently labelled Piezo1 ion channels in DHBs and verified activity using electrophysiology in the same system. We demonstrate successful insertion and activation of hPiezo1-GFP in bilayers of varying composition. Furthermore, we compare the Piezo1 bilayer reconstitution with measurements of insertion and activation of KcsA channels to reproduce the channel conductances reported in the literature. Together, our results showcase the use of DHBs for future experiments allowing simultaneous measurements of ion channel gating while visualising the channel proteins using fluorescence.

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The role of reactive oxygen and nitrogen species in airway epithelial gene expression.

Environmental Health Perspectives ◽

10.1289/ehp.98106s51197 ◽

1998 ◽

Vol 106 (suppl 5) ◽

pp. 1197-1203 ◽

Cited By ~ 11

Author(s):

L D Martin ◽

T M Krunkosky ◽

J A Voynow ◽

K B Adler

Keyword(s):

Gene Expression ◽

Reactive Oxygen ◽

Airway Epithelial ◽

Nitrogen Species

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Neuromodulation-dependent regulation of coordinated patterns of gene expression in motor neurons of the stomatogastric ganglion

10.32469/10355/43193 ◽

2012 ◽

Author(s):

◽

Simone Temporal

Keyword(s):

Gene Expression ◽

Ion Channels ◽

Potassium Channels ◽

Calcium Channels ◽

Ion Channel ◽

Mrna Expression ◽

Stomatogastric Ganglion ◽

Muscarinic Agonist ◽

Burst Frequency ◽

Network Function

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The pyloric network of the crustacean stomatogastric ganglion (STG) is a central pattern generator that requires descending modulation for normal ongoing rhythmic activity. However, the pyloric rhythm is capable of functional recovery after removal of descending inputs. We used the STG to determine whether or not correlated mRNA ion channels are dependent on neuromodulation. Our hypothesis is that relationships between ion channels are dependent on neuromodulation, not activity. To investigate this, we first measured mRNA expression levels of three calcium channels (Ca1A, Ca1D and T-type-related channel) and two potassium channels (shal and shab), of PD cells to investigate how channel transcription may be modified to influence recovery of burst activity. We collected single PD neurons from both recovered and time-matched control preparations and quantified channel transcript levels with quantitative real-time RT-PCR. There was widespread correlation between all three calcium channels and the two potassium channels in PD cells from intact networks. Specifically, the strongest relationships were between all three calcium channels and the shal channel, which carries an A-type transient potassium current (p[less-than]0.005; R2[greater-than]0.5). Furthermore, our results show that following recovery, there are no significant changes in overall mRNA abundance across all channel types. However, there was a striking lack of any correlation between measured channel types in PD cells following recovery. These results indicate that recovered, decentralized networks do not regain rhythmicity simply by increasing or decreasing mRNA expression for a given channel or channels. In order to determine whether ion channel correlations are dependent on neuromodulation or activity, we decoupled neuromodulatory and activity inputs. We found that preparations with neuromodulatory inputs maintained relationships between mRNA channels while activity input alone did not. Further, addition of pilocarpine, the muscarinic agonist and modulator, to decentralized preparations maintained the same correlations as those found in preparations that only had neuromodulatory input. To determine whether loss of correlations affected network function, we compared the pyloric burst frequency of the different conditions. We found that the pyloric burst frequency decreased under conditions that lost correlations between ion channels due to the removal of neuromodulation. Together, these results indicate that neuromodulation maintains ion channel correlations, which are important to proper network function. They also suggest a possible novel role of neuromodulation in the regulation of gene expression.

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