Structure of the human voltage-gated sodium channel Nav1.4 in complex with β1

Science ◽  
2018 ◽  
Vol 362 (6412) ◽  
pp. eaau2486 ◽  
Author(s):  
Xiaojing Pan ◽  
Zhangqiang Li ◽  
Qiang Zhou ◽  
Huaizong Shen ◽  
Kun Wu ◽  
...  
Keyword(s):  
Model Building ◽  
Fast Inactivation ◽  
Potential Generation ◽  
Voltage Gated ◽  
Cryo Electron Microscopy ◽  
Disease Mutations ◽  
Mechanistic Investigation ◽  
Pore Domain ◽  
Blocking Mechanism ◽  
Insight Into

Voltage-gated sodium (Nav) channels, which are responsible for action potential generation, are implicated in many human diseases. Despite decades of rigorous characterization, the lack of a structure of any human Nav channel has hampered mechanistic understanding. Here, we report the cryo–electron microscopy structure of the human Nav1.4-β1 complex at 3.2-Å resolution. Accurate model building was made for the pore domain, the voltage-sensing domains, and the β1 subunit, providing insight into the molecular basis for Na+ permeation and kinetic asymmetry of the four repeats. Structural analysis of reported functional residues and disease mutations corroborates an allosteric blocking mechanism for fast inactivation of Nav channels. The structure provides a path toward mechanistic investigation of Nav channels and drug discovery for Nav channelopathies.

P1597Two novel mutations in SCN5A gene cause enhanced inactivation and lead to Brugada syndrome

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
A Zaytseva ◽  
A V Karpushev ◽  
A V Karpushev ◽  
Y Fomicheva ◽  
Y Fomicheva ◽  
...  
Keyword(s):  
Steady State ◽  
Sodium Channel ◽  
Brugada Syndrome ◽  
Slow Inactivation ◽  
Fast Inactivation ◽  
Novel Mutations ◽  
Patch Clamp Technique ◽  
Inactivation Curve ◽  
Voltage Gated ◽  
Cardiac Sodium Channel

Abstract Background Mutations in gene SCN5A, encoding cardiac potential-dependent sodium channel Nav1.5, are associated with various arrhythmogenic disorders among which the Brugada syndrome (BrS) and the Long QT syndrome (LQT) are the best characterized. BrS1 is associated with sodium channel dysfunction, which can be reflected by decreased current, impaired activation and enhanced inactivation. We found two novel mutations in our patients with BrS and explored their effect on fast and slow inactivation of cardiac sodium channel. Purpose The aim of this study was to investigate the effect of BrS (Y739D, L1582P) mutations on different inactivation processes in in vitro model. Methods Y739D and L1582P substitutions were introduced in SCN5A cDNA using site-directed mutagenesis. Sodium currents were recorded at room temperature in transfected HEK293-T cells using patch-clamp technique with holding potential −100 mV. In order to access the fast steady-state inactivation curve we used double-pulse protocol with 10 ms prepulses. To analyze voltage-dependence of slow inactivation we used two-pulse protocol with 10s prepulse, 20ms test pulse and 25ms interpulse at −100mV to allow recovery from fast inactivation. Electrophysiological measurements are presented as mean ±SEM. Results Y739D mutation affects highly conserved tyrosine 739 among voltage-gated sodium and calcium channels in the segment IIS2. Mutation L1582P located in the loop IVS4-S5, and leucine in this position is not conserved among voltage-gated channels superfamily. We have shown that Y739D leads to significant changes in both fast and slow inactivation, whereas L1582P enhanced slow inactivation only. Steady-state fast inactivation for Y739D was shifted on 8.9 mV towards more negative potentials compare with that for WT, while L1582P did not enhanced fast inactivation (V1/2 WT: −62.8±1.7 mV; Y739D: −71.7±2.3 mV; L1582P: −58.7±1.4 mV). Slow inactivation was increased for both substitutions (INa (+20mV)/INa (−100mV) WT: 0.45±0.03; Y739D: 0,34±0.09: L1582P: 0.38±0.04). Steady-state fast inactivation Conclusions Both mutations, observed in patients with Brugada syndrome, influence on the slow inactivation process. Enhanced fast inactivation was shown only for Y739D mutant. The more dramatic alterations in sodium channel biophysical characteristics are likely linked with mutated residue conservativity. Acknowledgement/Funding RSF #17-15-01292

scholarly journals Proton Sensors in the Pore Domain of the Cardiac Voltage-gated Sodium Channel

2013 ◽  
Vol 288 (7) ◽  
pp. 4782-4791 ◽  
Author(s):  
David K. Jones ◽  
Colin H. Peters ◽  
Charlene R. Allard ◽  
Tom W. Claydon ◽  
Peter C. Ruben
Keyword(s):  
Sodium Channel ◽  
Voltage Gated Sodium Channel ◽  
Voltage Gated ◽  
Pore Domain

scholarly journals Insight into the RNA Exosome Complex Through Modeling Pontocerebellar Hypoplasia Type 1b Disease Mutations in Yeast

Genetics ◽  
2016 ◽  
Vol 205 (1) ◽  
pp. 221-237 ◽  
Author(s):  
Milo B. Fasken ◽  
Jillian S. Losh ◽  
Sara W. Leung ◽  
Sergine Brutus ◽  
Brittany Avin ◽  
...  
Keyword(s):  
Pontocerebellar Hypoplasia ◽  
Disease Mutations ◽  
Rna Exosome ◽  
Insight Into ◽  
Exosome Complex

scholarly journals Brief structural insight into the allosteric gating mechanism of BK (Slo1) channel

2019 ◽  
Vol 97 (6) ◽  
pp. 498-502
Author(s):  
János Almássy ◽  
Péter P. Nánási
Keyword(s):  
Quaternary Structure ◽  
Short Review ◽  
Bk Channel ◽  
The Past ◽  
Gating Model ◽  
Cryo Electron Microscopy ◽  
Gating Mechanism ◽  
Electrophysiological Measurements ◽  
Structural Insight ◽  
Insight Into

The big conductance Ca2+-dependent K+ channel, also known as BK, MaxiK, Slo1, or KCa1.1, is a ligand- and voltage-gated K+ channel. Although structure-function studies of the past decades, involving mutagenesis and electrophysiological measurements, revealed fine details of the mechanism of BK channel gating, the exact molecular details remained unknown until the quaternary structure of the protein has been solved at a resolution of 3.5 Å using cryo-electron microscopy. In this short review, we are going to summarize these results and interpret the gating model of the BK channel in the light of the recent structural results.

scholarly journals Modulation of Kv2.1 channel gating and TEA sensitivity by distinct domains of SNAP-25

2006 ◽  
Vol 396 (2) ◽  
pp. 363-369 ◽  
Author(s):  
Yan He ◽  
Youhou Kang ◽  
Yuk-Man Leung ◽  
Fuzhen Xia ◽  
Xiaodong Gao ◽  
...  
Keyword(s):  
Hormone Secretion ◽  
Channel Gating ◽  
Receptor Proteins ◽  
Cell Excitability ◽  
Voltage Gated ◽  
Channel Inactivation ◽  
Protein Receptor ◽  
Outer Pore ◽  
Pore Domain ◽  
Protein Attachment

Distinct domains within the SNARE (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor) proteins, STX1A (syntaxin 1A) and SNAP-25 (synaptosome-associated protein-25 kDa), regulate hormone secretion by their actions on the cell's exocytotic machinery, as well as voltage-gated Ca2+ and K+ channels. We examined the action of distinct domains within SNAP-25 on Kv2.1 (voltage gated K+ 2.1) channel gating. Dialysis of N-terminal SNAP-25 domains, S197 (SNAP-251–197) and S180 (SNAP-251–180), but not S206 (full-length SNAP-251–206) increased the rate of Kv2.1 channel activation and slowed channel inactivation. Remarkably, these N-terminal SNAP-25 domains, acting on the Kv2.1 cytoplasmic N-terminus, potentiated the external TEA (tetraethylammonium)-mediated block of Kv2.1. To further examine whether these are effects of the channel pore domain, internal K+ was replaced with Na+ and external K+ was decreased from 4 to 1 mM, which decreased the IC50 of the TEA block from 6.8±0.9 mM to >100 mM. Under these conditions S180 completely restored TEA sensitivity (7.9±1.5 mM). SNAP-25 C-terminal domains, SNAP-25198–206 and SNAP-25181–197, had no effect on Kv2.1 gating kinetics. We conclude that different domains within SNAP-25 can form distinct complexes with Kv2.1 to execute a fine allosteric regulation of channel gating and the architecture of the outer pore structure in order to modulate cell excitability.

Cryo-EM structure of the human cohesin-NIPBL-DNA complex

Science ◽  
2020 ◽  
Vol 368 (6498) ◽  
pp. 1454-1459 ◽  
Author(s):  
Zhubing Shi ◽  
Haishan Gao ◽  
Xiao-chen Bai ◽  
Hongtao Yu
Keyword(s):  
Electron Microscopy ◽  
Sister Chromatid ◽  
Base Pair ◽  
Adenosine Triphosphatase ◽  
Cryo Electron Microscopy ◽  
Synergistic Activation ◽  
Medium Resolution ◽  
Chromatid Cohesion ◽  
Dna Complex ◽  
Insight Into

As a ring-shaped adenosine triphosphatase (ATPase) machine, cohesin organizes the eukaryotic genome by extruding DNA loops and mediates sister chromatid cohesion by topologically entrapping DNA. How cohesin executes these fundamental DNA transactions is not understood. Using cryo–electron microscopy (cryo-EM), we determined the structure of human cohesin bound to its loader NIPBL and DNA at medium resolution. Cohesin and NIPBL interact extensively and together form a central tunnel to entrap a 72–base pair DNA. NIPBL and DNA promote the engagement of cohesin’s ATPase head domains and ATP binding. The hinge domains of cohesin adopt an “open washer” conformation and dock onto the STAG1 subunit. Our structure explains the synergistic activation of cohesin by NIPBL and DNA and provides insight into DNA entrapment by cohesin.

scholarly journals Cryo-EM structures of the DCPIB-inhibited volume-regulated anion channel LRRC8A in lipid nanodiscs

2018 ◽  
Author(s):  
David M. Kern ◽  
SeCheol Oh ◽  
Richard K. Hite ◽  
Stephen G. Brohawn
Keyword(s):  
Lipid Bilayers ◽  
Critical Role ◽  
Anion Channel ◽  
Lipid Binding ◽  
Channel Structure ◽  
Anion Channels ◽  
Cryo Electron Microscopy ◽  
Lipid Nanodiscs ◽  
Insight Into

AbstractHypoosmotic conditions activate volume-regulated anion channels in vertebrate cells. These channels are formed by leucine-rich repeat-containing protein 8 (LRRC8) family members and contain LRRC8A in homo- or hetero-hexameric assemblies. Here we present single-particle cryo-electron microscopy structures of LRRC8A in complex with the inhibitor DCPIB reconstituted in lipid nanodiscs. DCPIB plugs the channel like a cork in a bottle - binding in the extracellular selectivity filter and sterically occluding ion conduction. Constricted and expanded structures reveal coupled dilation of cytoplasmic LRRs and the channel pore, suggesting a mechanism for channel gating by internal stimuli. Conformational and symmetry differences between LRRC8A structures determined in detergent micelles and lipid bilayers related to reorganization of intersubunit lipid binding sites demonstrate a critical role for the membrane in determining channel structure. These results provide insight into LRRC8 gating and inhibition and the role of lipids in the structure of an ionic-strength sensing ion channel.

scholarly journals A surface plasmon resonance approach to monitor toxin interactions with an isolated voltage-gated sodium channel paddle motif

2015 ◽  
Vol 145 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Marie-France Martin-Eauclaire ◽  
Géraldine Ferracci ◽  
Frank Bosmans ◽  
Pierre E. Bougis
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Polarized Light ◽  
Voltage Sensor ◽  
Label Free ◽  
Fast Inactivation ◽  
Scorpion Toxins ◽  
Voltage Gated ◽  
Do So

Animal toxins that inhibit voltage-gated sodium (Nav) channel fast inactivation can do so through an interaction with the S3b–S4 helix-turn-helix region, or paddle motif, located in the domain IV voltage sensor. Here, we used surface plasmon resonance (SPR), an optical approach that uses polarized light to measure the refractive index near a sensor surface to which a molecule of interest is attached, to analyze interactions between the isolated domain IV paddle and Nav channel–selective α-scorpion toxins. Our SPR analyses showed that the domain IV paddle can be removed from the Nav channel and immobilized on sensor chips, and suggest that the isolated motif remains susceptible to animal toxins that target the domain IV voltage sensor. As such, our results uncover the inherent pharmacological sensitivities of the isolated domain IV paddle motif, which may be exploited to develop a label-free SPR approach for discovering ligands that target this region.

Uterine Excitability and Ion Channels and Their Changes with Gestation and Hormonal Environment

2020 ◽  
Vol 83 (1) ◽  
Author(s):  
Susan Wray ◽  
Sarah Arrowsmith
Keyword(s):  
Ion Channels ◽  
Inward Rectifier ◽  
Cation Channels ◽  
Annual Review ◽  
Publication Date ◽  
K Channels ◽  
Voltage Gated ◽  
New Findings ◽  
Voltage Dependent ◽  
Pore Domain

We address advances in the understanding of myometrial physiology, focusing on excitation and the effects of gestation on ion channels and their relevance to labor. This review moves through pioneering studies to exciting new findings. We begin with the myometrium and its myocytes and describe how excitation might initiate and spread in this myogenic smooth muscle. We then review each of the ion channels in the myometrium: L- and T-type Ca2+ channels, KATP (Kir6) channels, voltage-dependent K channels (Kv4, Kv7, and Kv11), twin-pore domain K channels (TASK, TREK), inward rectifier Kir7.1, Ca2+-activated K+ channels with large (KCNMA1, Slo1), small (KCNN1–3), and intermediate (KCNN4) conductance, Na-activated K channels (Slo2), voltage-gated (SCN) Na+ and Na+ leak channels, nonselective (NALCN) channels, the Na K-ATPase, and hyperpolarization-activated cation channels. We finish by assessing how three key hormones— oxytocin, estrogen, and progesterone—modulate and integrate excitability throughout gestation. Expected final online publication date for the Annual Review of Physiology, Volume 83 is February 10, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

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