keyword
MENU ▼
Read by QxMD icon Read
search

voltage gated potassium channel

keyword
https://www.readbyqxmd.com/read/27922120/regulation-of-human-cardiac-potassium-channels-by-full-length-kcne3-and-kcne4
#1
Geoffrey W Abbott
Voltage-gated potassium (Kv) channels comprise pore-forming α subunits and a multiplicity of regulatory proteins, including the cardiac-expressed and cardiac arrhythmia-linked transmembrane KCNE subunits. After recently uncovering novel, N-terminally extended (L) KCNE3 and KCNE4 isoforms and detecting their transcripts in human atrium, reported here are their functional effects on human cardiac Kv channel α subunits expressed in Xenopus laevis oocytes. As previously reported for short isoforms KCNE3S and KCNE4S, KCNE3L inhibited hERG; KCNE4L inhibited Kv1...
December 6, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27919210/three-dimensional-modelling-of-the-voltage-gated-sodium-ion-channel-from-anopheles-gambiae-reveals-spatial-clustering-of-evolutionarily-conserved-acidic-residues-at-the-extracellular-sites
#2
Rithvik S Vinekar, Ramanathan Sowdhamini
The eukaryotic voltage-gated sodium channel(e-Nav) is a large asymmetric transmembrane protein with important functions concerning neurological function. No structure has been resolved at high resolution for this protein. A homology model of the transmembrane and extracellular regions of an Anopheles gambiae para-like channel with emphasis on the pore entrance has been constructed, based upon the templates provided by a prokaryotic sodium channel and a potassium two-pore channel. The latter provides a template for the extracellular regions, which are located above the entrance to the pore, which is likely to open at a side of a dome formed by these loops...
December 5, 2016: Current Neuropharmacology
https://www.readbyqxmd.com/read/27916464/subtype-specific-block-of-voltage-gated-k-channels-by-%C3%AE-conopeptides
#3
Enrico Leipold, Florian Ullrich, Markus Thiele, Alesia A Tietze, Heinrich Terlau, Diana Imhof, Stefan H Heinemann
The neurotoxic cone snail peptide μ-GIIIA specifically blocks skeletal muscle voltage-gated sodium (NaV1.4) channels. The related conopeptides μ-PIIIA and μ-SIIIA, however, exhibit a wider activity spectrum by also inhibiting the neuronal NaV channels NaV1.2 and NaV1.7. Here we demonstrate that those μ-conopeptides with a broader target range also antagonize select subtypes of voltage-gated potassium channels of the KV1 family: μ-PIIIA and μ-SIIIA inhibited KV1.1 and KV1.6 channels in the nanomolar range, while being inactive on subtypes KV1...
December 1, 2016: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/27913935/regulation-of-contractile-responses-of-vascular-smooth-muscle-cells-under-conditions-of-hypoxia-reoxygenation
#4
S V Gusakova, Yu G Birulina, L V Smagliy, I V Kovalev, I V Petrova, A V Nosarev, S N Orlov
We analyzed the effects of hypoxia and reoxygenation on changes in contractile activity in rat aortic smooth muscles. Both hypoxia and reoxygenation induced relaxation of smooth muscle cells precontracted with high-potassium Krebs solution (30 mM KCl) or α1-adrenoceptor agonist phenylephrine. Vasodilation resulted from enhancement of potassium permeability of smooth muscle cell membranes caused by activation of voltage-gated potassium channels (triggered by both precontracting agents) or by opening of ATP-sensitive potassium channels (phenylephrine)...
December 2, 2016: Bulletin of Experimental Biology and Medicine
https://www.readbyqxmd.com/read/27874088/g9a-participates-in-nerve-injury-induced-kcna2-downregulation-in-primary-sensory-neurons
#5
Lingli Liang, Xiyao Gu, Jian-Yuan Zhao, Shaogen Wu, Xuerong Miao, Jifang Xiao, Kai Mo, Jun Zhang, Brianna Marie Lutz, Alex Bekker, Yuan-Xiang Tao
Nerve injury-induced downregulation of voltage-gated potassium channel subunit Kcna2 in the dorsal root ganglion (DRG) is critical for DRG neuronal excitability and neuropathic pain genesis. However, how nerve injury causes this downregulation is still elusive. Euchromatic histone-lysine N-methyltransferase 2, also known as G9a, methylates histone H3 on lysine residue 9 to predominantly produce a dynamic histone dimethylation, resulting in condensed chromatin and gene transcriptional repression. We showed here that blocking nerve injury-induced increase in G9a rescued Kcna2 mRNA and protein expression in the axotomized DRG and attenuated the development of nerve injury-induced pain hypersensitivity...
November 22, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27872215/intramolecular-interactions-that-control-voltage-sensitivity-in-the-jshak1-potassium-channel-from-polyorchis-penicillatus
#6
Nazlee Sharmin, Warren J Gallin
Voltage-gated potassium ion (Kv) channel proteins respond to changes in membrane potential by changing the probability of K(+) flux through an ion-selective pore. Kv channels from different paralogous and orthologous families have widely varying V50 values. The voltage-sensing transmembrane helices (S4) of different channels contain 4-7 basic residues that are responsible for transducing changes in transmembrane potential into the energy required to shift the equilibrium between the open- and closed-channel conformations...
November 21, 2016: Journal of Experimental Biology
https://www.readbyqxmd.com/read/27861921/potassium-channels-in-the-heart-structure-function-and-regulation
#7
Eleonora Grandi, Michael C Sanguinetti, Daniel C Bartos, Donald M Bers, Ye Chen-Izu, Nipavan Chiamvimonvat, Henry M Colecraft, Brian P Delisle, Jordi Heijman, Manuel F Navedo, Sergei Noskov, Catherine Proenza, Jamie I Vandenberg, Vladimir Yarov-Yarovoy
This paper is the outcome of the fourth UC Davis Systems Approach to Understanding Cardiac Excitation-Contraction Coupling and Arrhythmias Symposium, a biannual event that aims to bring together leading experts in subfields of cardiovascular biomedicine to focus on topics of importance to the field. The theme of the 2016 symposium was 'K(+) Channels and Regulation'. Experts in the field contributed their experimental and mathematical modelling perspectives and discussed emerging questions, controversies and challenges on the topic of cardiac K(+) channels...
November 13, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27861914/a-unifying-hypothesis-for-m1-muscarinic-receptor-signalling-in-pyramidal-neurons
#8
Sameera Dasari, Corey Hill, Allan T Gulledge
Gq -coupled muscarinic acetylcholine (ACh) receptors (mAChRs) mediate two distinct electrophysiological responses in cortical pyramidal neurons: transient inhibition driven by calcium-dependent small conductance potassium ("SK") channels, and longer-lasting and voltage-dependent excitation involving non-specific cation channels. Here we examine the interaction of these two cholinergic responses with respect to their contributions to intracellular calcium dynamics, testing the unifying hypothesis that rundown of inhibitory SK responses at resting membrane potentials (RMPs) reflects depletion of intracellular calcium stores, while mAChR-driven excitation acts to refill those stores by promoting voltage-dependent entry of extracellular calcium...
November 12, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27861889/margatoxin-bound-quantum-dots-as-a-novel-inhibitor-of-the-voltage-gated-ion-channel-kv1-3
#9
Austin B Schwartz, Anshika Kapur, Wentao Wang, Zhenbo Huang, Erminia Fardone, Goutam Palui, Hedi Mattoussi, Debra Ann Fadool
Venom-derived ion channel inhibitors have strong channel selectivity, potency, and stability; however, tracking delivery to their target can be challenging. Herein, we utilized luminescent quantum dots (QDs) conjugated to margatoxin (MgTx) as a traceable vehicle to target a voltage-dependent potassium channel, Kv1.3, which has a select distribution and well characterized role in immunity, glucose metabolism, and sensory ability. We screened both unconjugated (MgTx) and conjugated MgTx (QD-MgTx) for their ability to inhibit Shaker channels Kv1...
November 8, 2016: Journal of Neurochemistry
https://www.readbyqxmd.com/read/27861228/seronegative-bulbar-myasthenia-gravis-associated-with-voltage-gated-potassium-channel-antibodies
#10
Taofik Nasrat, Wensa Esarraj, Maher Fakhouri, Edwin George
No abstract text is available yet for this article.
December 2016: Journal of Clinical Neuromuscular Disease
https://www.readbyqxmd.com/read/27856205/differential-expression-of-romk-and-kcnq1-potassium-channels-in-bladder-urothelium-of-patients-with-interstitial-cystitis-painful-bladder-syndrome
#11
Jane-Dar Lee, Ming-Huei Lee, Wen-Kai Yang, Kuan-Lin Wang, Tsung-Han Lee
OBJECTIVE: To investigate the changes including expression and localization of two potassium channels, renal outer medullary K(+) channel (ROMK) and voltage-gated K(+) channel 7.1 (KCNQ1), after increased urinary potassium leakage in patients with interstitial cystitis/painful bladder syndrome (IC/PBS). METHODS: The study group included 24 patients with IC/PBS and a control group consisting of 12 volunteers without any IC/PBS symptoms. Bladder biopsies were taken from both groups...
November 14, 2016: Urology
https://www.readbyqxmd.com/read/27853286/disulfide-mapping-the-voltage-sensing-mechanism-of-a-voltage-dependent-potassium-channel
#12
Tomohiro Nozaki, Shin-Ichiro Ozawa, Hitomi Harada, Tomomi Kimura, Masanori Osawa, Ichio Shimada
Voltage-dependent potassium (Kv) channels allow for the selective permeability of potassium ions in a membrane potential dependent manner, playing crucial roles in neurotransmission and muscle contraction. Kv channel is a tetramer, in which each subunit possesses a voltage-sensing domain (VSD) and a pore domain (PD). Although several lines of evidence indicated that membrane depolarization is sensed as the movement of helix S4 of the VSD, the detailed voltage-sensing mechanism remained elusive, due to the difficulty of structural analyses at resting potential...
November 17, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27851471/1836-a-complicated-picture-of-voltage-gated-potassium-channel-antibody-disorder
#13
James Salonia, Steven Chakupurakal, Susannah Kurtz
No abstract text is available yet for this article.
December 2016: Critical Care Medicine
https://www.readbyqxmd.com/read/27847683/clinical-utility-of-seropositive-voltage-gated-potassium-channel-complex-antibody
#14
Adham Jammoul, Luay Shayya, Karin Mente, Jianbo Li, Alexander Rae-Grant, Yuebing Li
BACKGROUND: Antibodies against voltage-gated potassium channel (VGKC)-complex are implicated in the pathogenesis of acquired neuromyotonia, limbic encephalitis, faciobrachial dystonic seizure, and Morvan syndrome. Outside these entities, the clinical value of VGKC-complex antibodies remains unclear. METHODS: We conducted a single-center review of patients positive for VGKC-complex antibodies over an 8-year period. RESULTS: Among 114 patients positive for VGKC-complex antibody, 11 (9...
October 2016: Neurology. Clinical Practice
https://www.readbyqxmd.com/read/27836728/altered-gene-expression-profile-in-a-mouse-model-of-scn8a-encephalopathy
#15
Ryan S Sprissler, Jacy L Wagnon, Rosie K Bunton-Stasyshyn, Miriam H Meisler, Michael F Hammer
SCN8A encephalopathy is a severe, early-onset epilepsy disorder resulting from de novo gain-of-function mutations in the voltage-gated sodium channel Nav1.6. To identify the effects of this disorder on mRNA expression, RNA-seq was performed on brain tissue from a knock-in mouse expressing the patient mutation p.Asn1768Asp (N1768D). RNA was isolated from forebrain, cerebellum, and brainstem both before and after seizure onset, and from age-matched wildtype littermates. Altered transcript profiles were observed only in forebrain and only after seizures...
November 9, 2016: Experimental Neurology
https://www.readbyqxmd.com/read/27826710/the-action-of-smooth-muscle-cell-potassium-channels-in-the-pathology-of-pulmonary-arterial-hypertension
#16
REVIEW
Yasunobu Hayabuchi
Many different types of potassium channels with various functions exist in pulmonary artery smooth muscle cells, contributing to many physiological actions and pathological conditions. The deep involvement of these channels in the onset and exacerbation of pulmonary arterial hypertension (PAH) also continues to be revealed. In 2013, KCNK3 (TASK1), which encodes a type of two-pore domain potassium channel, was shown to be a predisposing gene for PAH by genetic mutation, and it was added to the PAH classification at the Fifth World Symposium on Pulmonary Hypertension (Nice International Conference)...
November 8, 2016: Pediatric Cardiology
https://www.readbyqxmd.com/read/27826078/participation-of-potassium-channels-in-the-antinociceptive-effect-of-docosahexaenoic-acid-in-the-rat-formalin-test
#17
Arizai Yolia Landa-Juárez, Mario I Ortiz, Gilberto Castañeda-Hernández, Aracely Evangelina Chávez-Piña
Docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid (PUFA) that has shown gastroprotective, cardioprotective, neuroprotective, anti-inflammatory and antinociceptive effects in different models. However, its action mechanism is still not well-defined. Reports indicate that some PUFAs regulate potassium (K(+)) channels in ventricular myocytes of rodents. As a result, the aim of this study was to evaluate the probable participation of K(+) channels in the antinociceptive effect of DHA. The rat paw 1% formalin test was used to assess nociception and antinociception...
December 15, 2016: European Journal of Pharmacology
https://www.readbyqxmd.com/read/27810559/interaction-site-for-the-inhibition-of-tarantula-jingzhaotoxin-xi-on-voltage-gated-potassium-channel-kv2-1
#18
Huai Tao, Xia Chen, Meichun Deng, Yucheng Xiao, Yuanyuan Wu, Zhonghua Liu, Sainan Zhou, Yingchun He, Songping Liang
Jingzhaotoxin-XI (JZTX-XI) is a 34-residue peptide from the Chinese tarantula Chilobrachys jingzhao venom that potently inhibits both voltage-gated sodium channel Nav1.5 and voltage-gated potassium channel Kv2.1. In the present study, we further showed that JZTX-XI blocked Kv2.1 currents with the IC50 value of 0.39 ± 0.06 μM. JZTX-XI significantly shifted the current-voltage (I-V) curves and normalized conductance-voltage (G-V) curves of Kv2.1 channel to more depolarized voltages. Ala-scanning mutagenesis analyses demonstrated that mutants I273A, F274A, and E277A reduced toxin binding affinity by 10-, 16-, and 18-fold, respectively, suggesting that three common residues (I273, F274, E277) in the Kv2...
December 15, 2016: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/27802162/the-c-terminal-domain-of-kv1-3-regulates-functional-interactions-with-the-kcne4-subunit
#19
Laura Solé, Sara R Roig, Albert Vallejo-Gracia, Antonio Serrano-Albarrás, Ramón Martínez-Mármol, Michael M Tamkun, Antonio Felipe
The voltage-dependent K(+) channel Kv1.3 (also known as KCNA3), which plays crucial roles in leukocytes, physically interacts with KCNE4. This interaction inhibits the K(+) currents because the channel is retained within intracellular compartments. Thus, KCNE subunits are regulators of K(+) channels in the immune system. Although the canonical interactions of KCNE subunits with Kv7 channels are under intensive investigation, the molecular determinants governing the important Kv1.3- KCNE4 association in the immune system are unknown...
November 15, 2016: Journal of Cell Science
https://www.readbyqxmd.com/read/27796577/regulation-of-human-cardiac-kv1-5-channels-by-extracellular-acidification
#20
Shuang Wang, Wei-Guang Ding, Jia-Yu Bai, Futoshi Toyoda, Min-Jie Wei, Hiroshi Matsuura
Human Kv1.5 channels (hKv1.5) conduct the ultra-rapid delayed rectifier potassium current (I Kur), which plays an important role in action potential repolarization of atrial myocytes. The present study was undertaken to examine the effects of acidic pH on hKv1.5 wild-type (WT) and its pore mutant channels heterologously expressed in Chinese hamster ovary (CHO) cells using site-directed mutagenesis combined with whole-cell patch-clamp technique. Both extracellular and intracellular acidifications equally and reversely reduced the amplitude of hKv1...
November 2016: Pflügers Archiv: European Journal of Physiology
keyword
keyword
73022
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"