Voltage-Gated Sodium Channel β1 Gene: An Overview

2021 ◽  
pp. 1-9
Author(s):  
Hisham Al-Ward ◽  
Chun-Yang Liu ◽  
Ning Liu ◽  
Fahmi Shaher ◽  
Murad Al-Nusaif ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Sodium Channels ◽  
Brugada Syndrome ◽  
Protein Complexes ◽  
Sodium Ion ◽  
Dravet Syndrome ◽  
Β Subunit ◽  
Voltage Gated ◽  
Physiological Processes ◽  
Voltage Gated Sodium Channels

<b><i>Background:</i></b> Voltage-gated sodium channels are protein complexes composed of 2 subunits, namely, pore-forming α- and regulatory β-subunits. A β-subunit consists of 5 proteins encoded by 4 genes (i.e., <i>SCN1B–SCN4B</i>). <b><i>Summary:</i></b> β<sub>1</sub>-Subunits regulate sodium ion channel functions, including gating properties, subcellular localization, and kinetics. <b><i>Key Message:</i></b> Sodium channel β<sub>1</sub>- and its variant β<sub>1B</sub>-subunits are encoded by <i>SCN1B</i>. These variants are associated with many human diseases, such as epilepsy, Brugada syndrome, Dravet syndrome, and cancers. On the basis of previous research, we aimed to provide an overview of the structure, expression, and involvement of <i>SCN1B</i> in physiological processes and focused on its role in diseases.

scholarly journals Sodium Channel Nav1.3 Is Expressed by Polymorphonuclear Neutrophils during Mouse Heart and Kidney Ischemia InVivo and Regulates Adhesion, Transmigration, and Chemotaxis of Human and Mouse Neutrophils In Vitro

2018 ◽  
Vol 128 (6) ◽  
pp. 1151-1166 ◽  
Author(s):  
Marit Poffers ◽  
Nathalie Bühne ◽  
Christine Herzog ◽  
Anja Thorenz ◽  
Rongjun Chen ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Sodium Channel ◽  
Sodium Channels ◽  
Polymorphonuclear Neutrophils ◽  
Human Neutrophils ◽  
Mouse Heart ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels

Abstract Background Voltage-gated sodium channels generate action potentials in excitable cells, but they have also been attributed noncanonical roles in nonexcitable cells. We hypothesize that voltage-gated sodium channels play a functional role during extravasation of neutrophils. Methods Expression of voltage-gated sodium channels was analyzed by polymerase chain reaction. Distribution of Nav1.3 was determined by immunofluorescence and flow cytometry in mouse models of ischemic heart and kidney injury. Adhesion, transmigration, and chemotaxis of neutrophils to endothelial cells and collagen were investigated with voltage-gated sodium channel inhibitors and lidocaine in vitro. Sodium currents were examined with a whole cell patch clamp. Results Mouse and human neutrophils express multiple voltage-gated sodium channels. Only Nav1.3 was detected in neutrophils recruited to ischemic mouse heart (25 ± 7%, n = 14) and kidney (19 ± 2%, n = 6) in vivo. Endothelial adhesion of mouse neutrophils was reduced by tetrodotoxin (56 ± 9%, unselective Nav-inhibitor), ICA121431 (53 ± 10%), and Pterinotoxin-2 (55 ± 9%; preferential inhibitors of Nav1.3, n = 10). Tetrodotoxin (56 ± 19%), ICA121431 (62 ± 22%), and Pterinotoxin-2 (59 ± 22%) reduced transmigration of human neutrophils through endothelial cells, and also prevented chemotactic migration (n = 60, 3 × 20 cells). Lidocaine reduced neutrophil adhesion to 60 ± 9% (n = 10) and transmigration to 54 ± 8% (n = 9). The effect of lidocaine was not increased by ICA121431 or Pterinotoxin-2. Conclusions Nav1.3 is expressed in neutrophils in vivo; regulates attachment, transmigration, and chemotaxis in vitro; and may serve as a relevant target for antiinflammatory effects of lidocaine.

scholarly journals Axons provide the secretory machinery for trafficking of voltage-gated sodium channels in peripheral nerve

2016 ◽  
Vol 113 (7) ◽  
pp. 1823-1828 ◽  
Author(s):  
Carolina González ◽  
José Cánovas ◽  
Javiera Fresno ◽  
Eduardo Couve ◽  
Felipe A. Court ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Sodium Channel ◽  
Sodium Channels ◽  
Neural Function ◽  
Axonal Membrane ◽  
Local Synthesis ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels

The regulation of the axonal proteome is key to generate and maintain neural function. Fast and slow axoplasmic waves have been known for decades, but alternative mechanisms to control the abundance of axonal proteins based on local synthesis have also been identified. The presence of the endoplasmic reticulum has been documented in peripheral axons, but it is still unknown whether this localized organelle participates in the delivery of axonal membrane proteins. Voltage-gated sodium channels are responsible for action potentials and are mostly concentrated in the axon initial segment and nodes of Ranvier. Despite their fundamental role, little is known about the intracellular trafficking mechanisms that govern their availability in mature axons. Here we describe the secretory machinery in axons and its contribution to plasma membrane delivery of sodium channels. The distribution of axonal secretory components was evaluated in axons of the sciatic nerve and in spinal nerve axons after in vivo electroporation. Intracellular protein trafficking was pharmacologically blocked in vivo and in vitro. Axonal voltage-gated sodium channel mRNA and local trafficking were examined by RT-PCR and a retention-release methodology. We demonstrate that mature axons contain components of the endoplasmic reticulum and other biosynthetic organelles. Axonal organelles and sodium channel localization are sensitive to local blockade of the endoplasmic reticulum to Golgi transport. More importantly, secretory organelles are capable of delivering sodium channels to the plasma membrane in isolated axons, demonstrating an intrinsic capacity of the axonal biosynthetic route in regulating the axonal proteome in mammalian axons.

scholarly journals Tracking S4 movement by gating pore currents in the bacterial sodium channel NaChBac

2014 ◽  
Vol 144 (2) ◽  
pp. 147-157 ◽  
Author(s):  
Tamer M. Gamal El-Din ◽  
Todd Scheuer ◽  
William A. Catterall
Keyword(s):  
Membrane Potential ◽  
Sodium Channel ◽  
Sodium Channels ◽  
Voltage Dependence ◽  
Periodic Paralysis ◽  
Membrane Potentials ◽  
Structural Basis ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
Gating Charges

Voltage-gated sodium channels mediate the initiation and propagation of action potentials in excitable cells. Transmembrane segment S4 of voltage-gated sodium channels resides in a gating pore where it senses the membrane potential and controls channel gating. Substitution of individual S4 arginine gating charges (R1–R3) with smaller amino acids allows ionic currents to flow through the mutant gating pore, and these gating pore currents are pathogenic in some skeletal muscle periodic paralysis syndromes. The voltage dependence of gating pore currents provides information about the transmembrane position of the gating charges as S4 moves in response to membrane potential. Here we studied gating pore current in mutants of the homotetrameric bacterial sodium channel NaChBac in which individual arginine gating charges were replaced by cysteine. Gating pore current was observed for each mutant channel, but with different voltage-dependent properties. Mutating the first (R1C) or second (R2C) arginine to cysteine resulted in gating pore current at hyperpolarized membrane potentials, where the channels are in resting states, but not at depolarized potentials, where the channels are activated. Conversely, the R3C gating pore is closed at hyperpolarized membrane potentials and opens with channel activation. Negative conditioning pulses revealed time-dependent deactivation of the R3C gating pore at the most hyperpolarized potentials. Our results show sequential voltage dependence of activation of gating pore current from R1 to R3 and support stepwise outward movement of the substituted cysteines through the narrow portion of the gating pore that is sealed by the arginine side chains in the wild-type channel. This pattern of voltage dependence of gating pore current is consistent with a sliding movement of the S4 helix through the gating pore. Through comparison with high-resolution models of the voltage sensor of bacterial sodium channels, these results shed light on the structural basis for pathogenic gating pore currents in periodic paralysis syndromes.

scholarly journals The periodic axon membrane skeleton leads to high-density sodium nanodomains but does not impact action potentials

2021 ◽  
Author(s):  
Zhaojie Chai ◽  
Anastasios V. Tzingonunis ◽  
George Lykotrafitis
Keyword(s):  
Sodium Channel ◽  
Sodium Channels ◽  
Action Potentials ◽  
High Density ◽  
Homogeneous Distribution ◽  
Voltage Gated ◽  
Periodic Distribution ◽  
Voltage Gated Sodium Channels ◽  
The Impact ◽  
Periodic Arrangement

ABSTRACTRecent work has established that axons have a periodic skeleton structure comprising of azimuthal actin rings connected via longitudinal spectrin tetramer filaments. This structure endows the axon with structural integrity and mechanical stability. Additionally, voltage-gated sodium channels follow the periodicity of the active-spectrin arrangement, spaced ∼190 nm segments apart. The impact of this periodic sodium channel arrangement on the generation and propagation of action potentials is unknown. To address this question, we simulated an action potential using the Hodgkin-Huxley formalism in a cylindrical compartment but instead of using a homogeneous distribution of voltage-gated sodium channels in the membrane, we applied the experimentally determined periodic arrangement. We found that the periodic distribution of voltage-gated sodium channels does not significantly affect the generation or propagation of action potentials, but instead leads to high-density sodium channel nanodomains. This work provides a foundation for future studies investigating the role of the voltage-gated sodium channel periodic arrangement in the axon.

scholarly journals Protonation state of inhibitors determines interaction sites within voltage-gated sodium channels

2018 ◽  
Vol 115 (14) ◽  
pp. E3135-E3144 ◽  
Author(s):  
Amanda Buyan ◽  
Delin Sun ◽  
Ben Corry
Keyword(s):  
Sodium Channel ◽  
Sodium Channels ◽  
The Body ◽  
Voltage Gated ◽  
Interaction Sites ◽  
Voltage Gated Sodium Channels ◽  
Neutral Compounds ◽  
Dynamics Simulations ◽  
A Site ◽  
Subtype Selective

Voltage-gated sodium channels are essential for carrying electrical signals throughout the body, and mutations in these proteins are responsible for a variety of disorders, including epilepsy and pain syndromes. As such, they are the target of a number of drugs used for reducing pain or combatting arrhythmias and seizures. However, these drugs affect all sodium channel subtypes found in the body. Designing compounds to target select sodium channel subtypes will provide a new therapeutic pathway and would maximize treatment efficacy while minimizing side effects. Here, we examine the binding preferences of nine compounds known to be sodium channel pore blockers in molecular dynamics simulations. We use the approach of replica exchange solute tempering (REST) to gain a more complete understanding of the inhibitors’ behavior inside the pore of NavMs, a bacterial sodium channel, and NavPas, a eukaryotic sodium channel. Using these simulations, we are able to show that both charged and neutral compounds partition into the bilayer, but neutral forms more readily cross it. We show that there are two possible binding sites for the compounds: (i) a site on helix 6, which has been previously determined by many experimental and computational studies, and (ii) an additional site, occupied by protonated compounds in which the positively charged part of the drug is attracted into the selectivity filter. Distinguishing distinct binding poses for neutral and charged compounds is essential for understanding the nature of pore block and will aid the design of subtype-selective sodium channel inhibitors.

scholarly journals Nedd4-2 (NEDD4L) controls intracellular Na+-mediated activity of voltage-gated sodium channels in primary cortical neurons

2013 ◽  
Vol 457 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Jenny A. Ekberg ◽  
Natasha A. Boase ◽  
Grigori Rychkov ◽  
Jantina Manning ◽  
Philip Poronnik ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Sodium Channels ◽  
Ubiquitin Ligase ◽  
Cortical Neurons ◽  
Channel Activity ◽  
Primary Cortical Neurons ◽  
Voltage Gated Sodium Channel ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
First Time

The study shows for the first time that the ubiquitin ligase Nedd4-2 regulates voltage-gated sodium channel activity in cortical neurons, specifically in response to elevated intracellular Na+ concentration.

scholarly journals Valproic acid interactions with the NavMs voltage-gated sodium channel

2019 ◽  
Vol 116 (52) ◽  
pp. 26549-26554 ◽  
Author(s):  
Geancarlo Zanatta ◽  
Altin Sula ◽  
Andrew J. Miles ◽  
Leo C. T. Ng ◽  
Rubben Torella ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Sodium Channel ◽  
Sodium Channels ◽  
Anticonvulsant Drug ◽  
Drug Binding ◽  
Voltage Sensor ◽  
Full Length ◽  
Binding Studies ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels

Valproic acid (VPA) is an anticonvulsant drug that is also used to treat migraines and bipolar disorder. Its proposed biological targets include human voltage-gated sodium channels, among other membrane proteins. We used the prokaryotic NavMs sodium channel, which has been shown to be a good exemplar for drug binding to human sodium channels, to examine the structural and functional interactions of VPA. Thermal melt synchrotron radiation circular dichroism spectroscopic binding studies of the full-length NavMs channel (which includes both pore and voltage sensor domains), and a pore-only construct, undertaken in the presence and absence of VPA, indicated that the drug binds to and destabilizes the channel, but not the pore-only construct. This is in contrast to other antiepileptic compounds that have previously been shown to bind in the central hydrophobic core of the pore region of the channel, and that tend to increase the thermal stability of both pore-only constructs and full-length channels. Molecular docking studies also indicated that the VPA binding site is associated with the voltage sensor, rather than the hydrophobic cavity of the pore domain. Electrophysiological studies show that VPA influences the block and inactivation rates of the NavMs channel, although with lower efficacy than classical channel-blocking compounds. It thus appears that, while VPA is capable of binding to these voltage-gated sodium channels, it has a very different mode and site of action than other anticonvulsant compounds.

scholarly journals Extremely Potent Block of Bacterial Voltage-Gated Sodium Channels by µ-Conotoxin PIIIA

Marine Drugs ◽  
2019 ◽  
Vol 17 (9) ◽  
pp. 510 ◽  
Author(s):  
Rocio K. Finol-Urdaneta ◽  
Jeffrey R. McArthur ◽  
Vyacheslav S. Korkosh ◽  
Sun Huang ◽  
Denis McMaster ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Sodium Channel ◽  
Sodium Channels ◽  
Cell Voltage ◽  
Hill Coefficient ◽  
Dependent Manner ◽  
Binding Modes ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
Conducting Pathway

µ-Conotoxin PIIIA, in the sub-picomolar, range inhibits the archetypal bacterial sodium channel NaChBac (NavBh) in a voltage- and use-dependent manner. Peptide µ-conotoxins were first recognized as potent components of the venoms of fish-hunting cone snails that selectively inhibit voltage-gated skeletal muscle sodium channels, thus preventing muscle contraction. Intriguingly, computer simulations predicted that PIIIA binds to prokaryotic channel NavAb with much higher affinity than to fish (and other vertebrates) skeletal muscle sodium channel (Nav 1.4). Here, using whole-cell voltage clamp, we demonstrate that PIIIA inhibits NavBac mediated currents even more potently than predicted. From concentration-response data, with [PIIIA] varying more than 6 orders of magnitude (10−12 to 10−5 M), we estimated an IC50 = ~5 pM, maximal block of 0.95 and a Hill coefficient of 0.81 for the inhibition of peak currents. Inhibition was stronger at depolarized holding potentials and was modulated by the frequency and duration of the stimulation pulses. An important feature of the PIIIA action was acceleration of macroscopic inactivation. Docking of PIIIA in a NaChBac (NavBh) model revealed two interconvertible binding modes. In one mode, PIIIA sterically and electrostatically blocks the permeation pathway. In a second mode, apparent stabilization of the inactivated state was achieved by PIIIA binding between P2 helices and trans-membrane S5s from adjacent channel subunits, partially occluding the outer pore. Together, our experimental and computational results suggest that, besides blocking the channel-mediated currents by directly occluding the conducting pathway, PIIIA may also change the relative populations of conducting (activated) and non-conducting (inactivated) states.

scholarly journals Solution Structure and Alanine Scan of a Spider Toxin That Affects the Activation of Mammalian Voltage-gated Sodium Channels

2006 ◽  
Vol 282 (7) ◽  
pp. 4643-4652 ◽  
Author(s):  
Gerardo Corzo ◽  
Jennifer K. Sabo ◽  
Frank Bosmans ◽  
Bert Billen ◽  
Elba Villegas ◽  
...  
Keyword(s):  
Sodium Channel ◽  
Sodium Channels ◽  
Solution Structure ◽  
Receptor Site ◽  
Amino Acid Sequences ◽  
Structural Motif ◽  
Dimensional Structure ◽  
Voltage Gated Sodium Channel ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels

Magi 5, from the hexathelid spider Macrothele gigas, is a 29-residue polypeptide containing three disulfide bridges. It binds specifically to receptor site 4 on mammalian voltage-gated sodium channels and competes with scorpion β-toxins, such as Css IV from Centruroides suffusus suffusus. As a consequence, Magi 5 shifts the activation voltage of the mammalian rNav1.2a channel to more hyperpolarized voltages, whereas the insect channel, DmNav1, is not affected. To gain insight into toxin-channel interactions, Magi 5 and 23 analogues were synthesized. The three-dimensional structure of Magi 5 in aqueous solution was determined, and its voltage-gated sodium channel-binding surfaces were mapped onto this structure using data from electrophysiological measurements on a series of Ala-substituted analogues. The structure clearly resembles the inhibitor cystine knot structural motif, although the triple-stranded β-sheet typically found in that motif is partially distorted in Magi 5. The interactive surface of Magi 5 toward voltage-gated sodium channels resembles in some respects the Janus-faced atracotoxins, with functionally important charged residues on one face of the toxin and hydrophobic residues on the other. Magi 5 also resembles the scorpion β-toxin Css IV, which has distinct nonpolar and charged surfaces that are critical for channel binding and has a key Glu involved in voltage sensor trapping. These two distinct classes of toxin, with different amino acid sequences and different structures, may utilize similar groups of residues on their surface to achieve the common end of modifying voltage-gated sodium channel function.

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