scholarly journals Voltage gated inter-cation selective ion channels from graphene nanopores

Nanoscale ◽  
2019 ◽  
Vol 11 (20) ◽  
pp. 9856-9861 ◽  
Author(s):  
Lauren Cantley ◽  
Jacob L. Swett ◽  
David Lloyd ◽  
David A. Cullen ◽  
Ke Zhou ◽  
...  
Keyword(s):  
Ion Channels ◽  
Ionic Transport ◽  
Voltage Gated ◽  
Nanoporous Graphene ◽  
Graphene Membranes

The role of nanobubbles in selectively controlled ionic transport across fabricated nanoporous graphene membranes is elucidated.

scholarly journals Domain–domain interactions determine the gating, permeation, pharmacology, and subunit modulation of the IKs ion channel

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Mark A Zaydman ◽  
Marina A Kasimova ◽  
Kelli McFarland ◽  
Zachary Beller ◽  
Panpan Hou ◽  
...  
Keyword(s):  
Ion Channels ◽  
Physiological Role ◽  
Specific Expression ◽  
Electrical Currents ◽  
Voltage Gated ◽  
State Dependent ◽  
Domain Interactions ◽  
Voltage Gated Ion Channels ◽  
Hormonal Release

Voltage-gated ion channels generate electrical currents that control muscle contraction, encode neuronal information, and trigger hormonal release. Tissue-specific expression of accessory (β) subunits causes these channels to generate currents with distinct properties. In the heart, KCNQ1 voltage-gated potassium channels coassemble with KCNE1 β-subunits to generate the IKs current (<xref ref-type="bibr" rid="bib3">Barhanin et al., 1996</xref>; <xref ref-type="bibr" rid="bib57">Sanguinetti et al., 1996</xref>), an important current for maintenance of stable heart rhythms. KCNE1 significantly modulates the gating, permeation, and pharmacology of KCNQ1 (<xref ref-type="bibr" rid="bib77">Wrobel et al., 2012</xref>; <xref ref-type="bibr" rid="bib66">Sun et al., 2012</xref>; <xref ref-type="bibr" rid="bib1">Abbott, 2014</xref>). These changes are essential for the physiological role of IKs (<xref ref-type="bibr" rid="bib62">Silva and Rudy, 2005</xref>); however, after 18 years of study, no coherent mechanism explaining how KCNE1 affects KCNQ1 has emerged. Here we provide evidence of such a mechanism, whereby, KCNE1 alters the state-dependent interactions that functionally couple the voltage-sensing domains (VSDs) to the pore.

scholarly journals Analysis of Single Nucleotide Polymorphisms in human Voltage-Gated Ion Channels

2018 ◽  
Author(s):  
Katerina C. Nastou ◽  
Michail A. Batskinis ◽  
Zoi I. Litou ◽  
Stavros J. Hamodrakas ◽  
Vassiliki A. Iconomidou
Keyword(s):  
Ion Channels ◽  
Single Nucleotide Polymorphisms ◽  
Nucleotide Polymorphisms ◽  
Topological Information ◽  
Single Nucleotide ◽  
Voltage Gated ◽  
Arginine Residues ◽  
Voltage Gated Ion Channels ◽  
Gated Ion Channels

AbstractVoltage-Gated Ion Channels (VGICs) are one of the largest groups of transmembrane proteins. Due to their major role in the generation and propagation of electrical signals, VGICs are considered important from a medical viewpoint and their dysfunction is often associated with a group of diseases known as “Channelopathies”. We identified disease associated mutations and polymorphisms in these proteins through mapping missense Single Nucleotide Polymorphisms (SNPs) from the UniProt and ClinVar databases on their amino acid sequence, taking into consideration their special topological and functional characteristics. Statistical analysis revealed that disease associated SNPs are mostly found in the Voltage Sensor Domain – and especially at its fourth transmembrane segment (S4) – and in the Pore Loop. Both these regions are extremely important for the activation and ion conductivity of VGICs. Moreover, amongst the most frequently observed mutations are those of arginine to glutamine, to histidine or to cysteine, which can probably be attributed to the extremely important role of arginine residues in the regulation of membrane potential in these proteins. We suggest that topological information in combination with genetic variation data can contribute towards a better evaluation of the effect of currently unclassified mutations in VGICs. It is hoped that potential associations with certain disease phenotypes will be revealed in the future, with the use of similar approaches.

scholarly journals Structure and Function of Ion Channels Regulating Sperm Motility—An Overview

2021 ◽  
Vol 22 (6) ◽  
pp. 3259
Author(s):  
Karolina Nowicka-Bauer ◽  
Monika Szymczak-Cendlak
Keyword(s):  
Ion Channels ◽  
Sperm Motility ◽  
Ion Homeostasis ◽  
Internal Factors ◽  
Voltage Gated ◽  
Secondary Messenger ◽  
Cl Channels ◽  
H Channels ◽  
And Function

Sperm motility is linked to the activation of signaling pathways that trigger movement. These pathways are mainly dependent on Ca2+, which acts as a secondary messenger. The maintenance of adequate Ca2+ concentrations is possible thanks to proper concentrations of other ions, such as K+ and Na+, among others, that modulate plasma membrane potential and the intracellular pH. Like in every cell, ion homeostasis in spermatozoa is ensured by a vast spectrum of ion channels supported by the work of ion pumps and transporters. To achieve success in fertilization, sperm ion channels have to be sensitive to various external and internal factors. This sensitivity is provided by specific channel structures. In addition, novel sperm-specific channels or isoforms have been found with compositions that increase the chance of fertilization. Notably, the most significant sperm ion channel is the cation channel of sperm (CatSper), which is a sperm-specific Ca2+ channel required for the hyperactivation of sperm motility. The role of other ion channels in the spermatozoa, such as voltage-gated Ca2+ channels (VGCCs), Ca2+-activated Cl-channels (CaCCs), SLO K+ channels or voltage-gated H+ channels (VGHCs), is to ensure the activation and modulation of CatSper. As the activation of sperm motility differs among metazoa, different ion channels may participate; however, knowledge regarding these channels is still scarce. In the present review, the roles and structures of the most important known ion channels are described in regard to regulation of sperm motility in animals.

scholarly journals Mining recent brain proteomic databases for ion channel phosphosite nuggets

2010 ◽  
Vol 137 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Oscar Cerda ◽  
Je-Hyun Baek ◽  
James S. Trimmer
Keyword(s):  
Ion Channels ◽  
Ion Channel ◽  
Mammalian Brain ◽  
Phosphorylation Sites ◽  
Dynamic Regulation ◽  
Voltage Gated ◽  
Voltage Gated Ion Channels ◽  
Α Subunits

Voltage-gated ion channels underlie electrical activity of neurons and are dynamically regulated by diverse cell signaling pathways that alter their phosphorylation state. Recent global mass spectrometric–based analyses of the mouse brain phosphoproteome have yielded a treasure trove of new data as to the extent and nature of phosphorylation of numerous ion channel principal or α subunits in mammalian brain. Here we compile and review data on 347 phosphorylation sites (261 unique) on 42 different voltage-gated ion channel α subunits that were identified in these recent studies. Researchers in the ion channel field can now begin to explore the role of these novel in vivo phosphorylation sites in the dynamic regulation of the localization, activity, and expression of brain ion channels through multisite phosphorylation of their principal subunits.

scholarly journals Calmodulin: A Multitasking Protein in Kv7.2 Potassium Channel Functions

Biomolecules ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 57 ◽  
Author(s):  
Alessandro Alaimo ◽  
Alvaro Villarroel
Keyword(s):  
Ion Channels ◽  
Potassium Channel ◽  
Critical Role ◽  
The Other ◽  
Eukaryotic Cells ◽  
Calcium Signals ◽  
Voltage Gated ◽  
Cellular Processes ◽  
Cam Regulation

The ubiquitous calcium transducer calmodulin (CaM) plays a pivotal role in many cellular processes, regulating a myriad of structurally different target proteins. Indeed, it is unquestionable that CaM is the most relevant transductor of calcium signals in eukaryotic cells. During the last two decades, different studies have demonstrated that CaM mediates the modulation of several ion channels. Among others, it has been indicated that Kv7.2 channels, one of the members of the voltage gated potassium channel family that plays a critical role in brain excitability, requires CaM binding to regulate the different mechanisms that govern its functions. The purpose of this review is to provide an overview of the most recent advances in structure–function studies on the role of CaM regulation of Kv7.2 and the other members of the Kv7 family.

Enhanced water permeation based on nanoporous multilayer graphene membranes: the role of pore size and density

2016 ◽  
Vol 4 (45) ◽  
pp. 17773-17781 ◽  
Author(s):  
Dae Woo Kim ◽  
Junghoon Choi ◽  
Daeok Kim ◽  
Hee-Tae Jung
Keyword(s):  
Pore Size ◽  
Koh Activation ◽  
Multilayer Graphene ◽  
Water Permeation ◽  
Nanoporous Graphene ◽  
Oxidized Graphite ◽  
Graphene Membranes

Nanoporous graphene (size: ca. 3 nm, density: ca. 1015 m−2) can be synthesized in bulk by KOH activation of pre-oxidized graphite.

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