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voltage gated potassium channel

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https://www.readbyqxmd.com/read/28808020/kcne1-and-kcne3-modulate-kcnq1-channels-by-affecting-different-gating-transitions
#1
Rene Barro-Soria, Rosamary Ramentol, Sara I Liin, Marta E Perez, Robert S Kass, H Peter Larsson
KCNE β-subunits assemble with and modulate the properties of voltage-gated K(+) channels. In the heart, KCNE1 associates with the α-subunit KCNQ1 to generate the slowly activating, voltage-dependent potassium current (IKs) in the heart that controls the repolarization phase of cardiac action potentials. By contrast, in epithelial cells from the colon, stomach, and kidney, KCNE3 coassembles with KCNQ1 to form K(+) channels that are voltage-independent K(+) channels in the physiological voltage range and important for controlling water and salt secretion and absorption...
August 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28802123/clathrodin-hymenidin-and-oroidin-and-their-synthetic-analogues-as-inhibitors-of-the-voltage-gated-potassium-channels
#2
Nace Zidar, Aleš Žula, Tihomir Tomašič, Marc Rogers, Robert W Kirby, Jan Tytgat, Steve Peigneur, Danijel Kikelj, Janez Ilaš, Lucija Peterlin Mašič
We have prepared three alkaloids from the Agelas sponges, clathrodin, hymenidin and oroidin, and a series of their synthetic analogues, and evaluated their inhibitory effect against six isoforms of the Kv1 subfamily of voltage-gated potassium channels, Kv1.1-Kv1.6, expressed in Chinese Hamster ovary (CHO) cells using automated patch clamp electrophysiology assay. The most potent inhibitor was the (E)-N-(3-(2-amino-1H-imidazol-4-yl)allyl)-4,5-dichloro-1H-pyrrole-2-carboxamide (6g) with IC50 values between 1...
August 7, 2017: European Journal of Medicinal Chemistry
https://www.readbyqxmd.com/read/28793216/smit1-modifies-kcnq-channel-function-and-pharmacology-by-physical-interaction-with-the-pore
#3
Rían W Manville, Daniel L Neverisky, Geoffrey W Abbott
Voltage-gated potassium channels of the KCNQ (Kv7) subfamily are essential for control of cellular excitability and repolarization in a wide range of cell types. Recently, we and others found that some KCNQ channels functionally and physically interact with sodium-dependent solute transporters, including myo-inositol transporters SMIT1 and SMIT2, potentially facilitating various modes of channel-transporter signal integration. In contrast to indirect effects such as channel regulation by SMIT-transported, myo-inositol-derived phosphatidylinositol 4,5-bisphosphate (PIP2), the mechanisms and functional consequences of the physical interaction of channels with transporters have been little studied...
August 8, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28791017/differentially-expressed-potassium-channels-are-associated-with-function-of-human-effector-memory-cd8-t-cells
#4
Ji Hyun Sim, Kyung Soo Kim, Hyoungjun Park, Kyung-Jin Kim, Haiyue Lin, Tae-Joo Kim, Hyun Mu Shin, Gwanghun Kim, Dong-Sup Lee, Chan-Wook Park, Dong Hun Lee, Insoo Kang, Sung Joon Kim, Chung-Hyun Cho, Junsang Doh, Hang-Rae Kim
The voltage-gated potassium channel, Kv1.3, and the Ca(2+)-activated potassium channel, KCa3.1, regulate membrane potentials in T cells, thereby controlling T cell activation and cytokine production. However, little is known about the expression and function of potassium channels in human effector memory (EM) CD8(+) T cells that can be further divided into functionally distinct subsets based on the expression of the interleukin (IL)-7 receptor alpha (IL-7Rα) chain. Herein, we investigated the functional expression and roles of Kv1...
2017: Frontiers in Immunology
https://www.readbyqxmd.com/read/28782041/a-bimodal-activation-mechanism-underlies-scorpion-toxin-induced-pain
#5
Shilong Yang, Fan Yang, Bei Zhang, Bo Hyun Lee, Bowen Li, Lei Luo, Jie Zheng, Ren Lai
Venomous animals use peptide toxins for hunting and self-defense. To achieve these goals, toxins need to bind to their targets with high affinity due to the small amount that a single bite or sting can deliver. The scorpion toxin BmP01 is linked to sting-induced excruciating pain; however, the reported minimum concentrations for activating TRPV1 channel or inhibiting voltage-gated potassium (Kv) channels (both in the micromolar range) appear too high to be biologically relevant. We show that the effective concentration of BmP01 is highly pH-dependent-it increases by about 10-fold in inhibiting Kv channels upon a 1-U drop in pH but decreases more than 100-fold in activating TRPV1...
August 2017: Science Advances
https://www.readbyqxmd.com/read/28780589/development-of-brain-ventricular-system
#6
REVIEW
Vladimir Korzh
The brain ventricular system (BVS) consists of brain ventricles and channels connecting ventricles filled with cerebrospinal fluid (CSF). The disturbance of CSF flow has been linked to neurodegenerative disease including hydrocephalus, which manifests itself as an abnormal expansion of BVS. This relatively common developmental disorder has been observed in human and domesticated animals and linked to functional deficiency of various cells lineages facing BVS, including the choroid plexus or ependymal cells that generate CSF or the ciliated cells that cilia beating generates CSF flow...
August 5, 2017: Cellular and Molecular Life Sciences: CMLS
https://www.readbyqxmd.com/read/28774677/conorfamide-sr3-a-structurally-novel-specific-inhibitor-of-the-shaker-k-channel
#7
Elba Campos-Lira, Elissa Carrillo, Manuel B Aguilar, Joanna Gajewiak, Froylán Gómez-Lagunas, Estuardo López-Vera
Conorfamides (CNFs) are toxins initially characterized from the venom duct of the venomous marine snail Conus spurius from the Gulf of Mexico; at their C-termini, these toxins are amidated and have high sequence similarity with the molluskan cardioexcitatory tetrapeptide Phe-Met-Arg-Phe-NH2 (FMRFamide or FMRFa) and other FMRFa-related peptides (FaRPs) found in the five molluskan classes, and in other invertebrate and vertebrate phyla. These peptides were the first FaRPs found to be present in any venom, and they are biologically active in mice, limpets, and/or freshwater snails...
July 31, 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28767591/identification-of-key-genes-associated-with-rheumatoid-arthritis-with-bioinformatics-approach
#8
Xiaokun Gang, Yan Sun, Fei Li, Tong Yu, Zhende Jiang, Xiujie Zhu, Qiyao Jiang, Yao Wang
We aimed to identify key genes associated with rheumatoid arthritis (RA).The microarray datasets of GSE1919, GSE12021, and GSE21959 (35 RA samples and 32 normal controls) were downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) in RA samples were identified using the t test in limma package. Functional enrichment analysis was performed using clusterProfiler package. A protein-protein interaction (PPI) network of selected DEGs was constructed based on the Human Protein Reference Database...
August 2017: Medicine (Baltimore)
https://www.readbyqxmd.com/read/28758418/intermittent-hypoxia-training-in-prediabetes-patients-beneficial-effects-on-glucose-homeostasis-hypoxia-tolerance-and-gene-expression
#9
Tetiana V Serebrovska, Alla G Portnychenko, Tetiana I Drevytska, Vladimir I Portnichenko, Lei Xi, Egor Egorov, Anna V Gavalko, Svitlana Naskalova, Valentina Chizhova, Valeriy B Shatylo
The present study aimed at examining beneficial effects of intermittent hypoxia training (IHT) under prediabetic conditions. We investigate the effects of three-week IHT on blood glucose level, tolerance to acute hypoxia, and leukocyte mRNA expression of hypoxia inducible factor 1α (HIF-1α) and its target genes, i.e. insulin receptor, facilitated glucose transporter-solute carrier family-2, and potassium voltage-gated channel subfamily J. Seven healthy and 11 prediabetic men and women (44-70 years of age) were examined before, next day and one month after three-week IHT (3 sessions per week, each session consisting 4 cycles of 5-min 12% O2 and 5-min room air breathing)...
January 1, 2017: Experimental Biology and Medicine
https://www.readbyqxmd.com/read/28751455/calcineurin-dysregulation-underlies-spinal-cord-injury-induced-k-channel-dysfunction-in-drg-neurons
#10
Benjamin M Zemel, Tanziyah Muqeem, Eric V Brown, Miguel Goulão, Mark W Urban, Stephen R Tymanskyj, Angelo C Lepore, Manuel Covarrubias
Dysfunction of the fast-inactivating Kv3.4 potassium current in dorsal root ganglion (DRG) neurons contributes to the hyperexcitability associated with persistent pain induced by spinal cord injury (SCI). However, the underlying mechanism is not known. In light of our previous work demonstrating modulation of the Kv3.4 channel by phosphorylation, we investigated the role of the phosphatase calcineurin (CaN) using electrophysiological, molecular and imaging approaches in adult Sprague-Dawley female rats. Pharmacological inhibition of CaN in small-diameter DRG neurons slows repolarization of the somatic action potential (AP) and attenuates the Kv3...
July 27, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28750836/a-likely-case-of-limbic-encephalitis-in-a-patient-with-voltage-gated-potassium-channel-complex-antibody-without-a-known-antigenic-target-a-review-of-the-disease-state-and-value-of-antibody-titers
#11
David R Spiegel, Anastasia Samaras, Cameron L Oldham, Meghana Kaloji, Alyssa Warren, Shannon Maj, Sharmeen R Husain, Jeremy I Solomons, Stephanie Le
No abstract text is available yet for this article.
June 1, 2017: Psychosomatics
https://www.readbyqxmd.com/read/28747510/nonspecific-block-of-voltage-gated-potassium-channels-has-greater-effect-on-distal-schaffer-collaterals-than-proximal-schaffer-collaterals-during-periods-of-high-activity
#12
Benjamin Owen, Rishi Reddy, Lawrence M Grover
Previous studies established different responses between proximal and distal portions of Schaffer collateral axons during high-frequency and burst stimulation, with distal axons demonstrating biphasic changes in excitability (hyperexcitability followed by depression), but proximal axons showing only monophasic depression. Voltage-dependent potassium (KV) channels are important determinants of axonal excitability, and block of KV channels can promote axon hyperexcitability. We therefore hypothesized that block of KV channels should lead to biphasic response changes in proximal Schaffer collaterals, like those seen in distal Schaffer collaterals...
July 2017: Physiological Reports
https://www.readbyqxmd.com/read/28747083/a-novel-variant-with-positive-natural-selection-influenced-hb-a2-levels-in-chinese-individuals-with-%C3%AE-thalassemia
#13
Shanjuan Yu, Yang Chen, Ketong Lai, Roma Kajal Dewan, Yunyan He
β-Thalassemia (β-thal) is the most common inherited hemolytic anemia worldwide. Elevated Hb A2 is a mark of β-thal carriers. The aim of this study was to identify the pathogenic variants associated with the Hb A2 levels. One thousand and thirty β-thal carriers were recruited for this study. Using positive natural expression quantitative trait loci (eQTL) analysis, a significant variant was selected. Genotyping for the rs231841 polymorphism was performed by the Sequenom MassARRAY IPLEX platform. All genetic association analyses were performed with the PLINK program...
July 26, 2017: Hemoglobin
https://www.readbyqxmd.com/read/28746852/photo-cross-linking-of-iks-demonstrates-state-dependent-interactions-between-kcne1-and-kcnq1
#14
Maartje Westhoff, Christopher I Murray, Jodene Eldstrom, David Fedida
The slow delayed rectifier potassium current (IKs) is a key repolarizing current during the cardiac action potential. It consists of four KCNQ1 α-subunits and up to four KCNE1 β-subunits, which are thought to reside within external clefts of the channel. The interaction of KCNE1 with KCNQ1 dramatically delays opening of the channel but the mechanisms by which this occur are not yet fully understood. Here, we have used unnatural amino acid photo-cross-linking to investigate the dynamic interactions that occur between KCNQ1 and KCNE1 during activation gating...
July 25, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28731153/altered-profile-of-mrna-expression-in-atrioventricular-node-of-streptozotocin%C3%A2-induced-diabetic-rats
#15
Frank Christopher Howarth, Khatija Parekh, Petrilla Jayaprakash, Edward Samuel Inbaraj, Murat Oz, Halina Dobrzynski, Thomas Edward Adrian
Prolonged action potential duration, reduced action potential firing rate, upstroke velocity and rate of diastolic depolarization have been demonstrated in atrioventricular node (AVN) cells from streptozotocin (STZ)‑induced diabetic rats. To further clarify the molecular basis of these electrical disturbances, the mRNA profiles encoding a variety of proteins associated with the generation and conduction of electrical activity in the AVN, were evaluated in the STZ‑induced diabetic rat heart. Expression of mRNA was measured in AVN biopsies using reverse transcription‑quantitative polymerase chain reaction techniques...
July 20, 2017: Molecular Medicine Reports
https://www.readbyqxmd.com/read/28728838/kcnq2-encephalopathy-a-case-due-to-a-de-novo-deletion
#16
Carlotta Spagnoli, Grazia Gabriella Salerno, Alessandro Iodice, Daniele Frattini, Francesco Pisani, Carlo Fusco
KCNQ2 encephalopathy is characterized by severely abnormal EEG, neonatal-onset epilepsy and developmental delay. It is caused by mutations (typically missense) in the KCNQ2 gene, encoding the voltage gated potassium channel Kv7.2 and leading to a negative-dominant effect. We present one case experiencing recurrent neonatal seizures with changing hemispheres of origin, reminiscent of epilepsy of infancy with migrating focal seizures. At 9months of age the patient is still seizure-free on carbamazepine, although he is developing a spastic-dystonic tetraplegia with severe dysphagia...
July 17, 2017: Brain & Development
https://www.readbyqxmd.com/read/28728818/mechanosensitive-piezo-channels-in-the-gastrointestinal-tract
#17
C Alcaino, G Farrugia, A Beyder
Sensation of mechanical forces is critical for normal function of the gastrointestinal (GI) tract and abnormalities in mechanosensation are linked to GI pathologies. In the GI tract there are several mechanosensitive cell types-epithelial enterochromaffin cells, intrinsic and extrinsic enteric neurons, smooth muscle cells and interstitial cells of Cajal. These cells use mechanosensitive ion channels that respond to mechanical forces by altering transmembrane ionic currents in a process called mechanoelectrical coupling...
2017: Current Topics in Membranes
https://www.readbyqxmd.com/read/28726567/possible-mechanisms-involved-in-the-anti-nociceptive-effects-of-hydro-ethanolic-leaf-extract-of-ziziphus-abyssinica
#18
Eric Boakye-Gyasi, Isaac Tabiri Henneh, Wonder Kofi Mensah Abotsi, Elvis Ofori Ameyaw, Eric Woode
CONTEXT: Various parts of Ziziphus abyssinica Hochst ex. A. Rich (Rhamnaceae) have been used in Ghanaian and African traditional medicine as an analgesic. However, there are little scientific data to support the anti-nociceptive effects of the hydro-ethanolic leaf extract of Ziziphus abyssinica (EthE) as well as the possible mechanisms involved in its anti-nociceptive effects. PURPOSE: To predict possible nociceptive pathways involved in the anti-nociceptive effects of EthE...
December 2017: Pharmaceutical Biology
https://www.readbyqxmd.com/read/28726484/annals-express-experience-with-newer-central-nervous-system-autoantibodies
#19
Abid Karim, Saiju Jacob
In the last decade, a large number of neuronal cell-surface antibodies have been described which are responsible for a range of neuroimmunological central nervous system disorders. Unlike the paraneoplastic antibodies which target intracellular antigens, these antibodies appear to be pathogenic and hence identification and prompt treatment can make a substantial impact on clinical outcomes of these patients. We review the common antibodies against the ionotropic Glutamate receptors (NMDAR, AMPAR), metabotropic Glutamate receptors (mGluR1 and mGluR5), voltage gated potassium channel-complex proteins (LGI1, CASPR2), and other antibodies targeted against Glycine receptor, Glutamic acid decarboxylase (GAD), Gamma Amino Butyric Acid B (GABAB), Dopamine-2-receptor (D2R) and Dipeptidyl-peptidase-like protein 6 (DPPX)...
January 1, 2017: Annals of Clinical Biochemistry
https://www.readbyqxmd.com/read/28718820/a-transcriptomic-survey-of-ion-channel-based-conotoxins-in-the-chinese-tubular-cone-snail-conus-betulinus
#20
Yu Huang, Chao Peng, Yunhai Yi, Bingmiao Gao, Qiong Shi
Conotoxins in the venom of cone snails (Conus spp.) are a mixture of active peptides that work as blockers, agonists, antagonists, or inactivators of various ion channels. Recently we reported a high-throughput method to identify 215 conotoxin transcripts from the Chinese tubular cone snail, C. betulinus. Here, based on the previous datasets of four transcriptomes from three venom ducts and one venom bulb, we explored ion channel-based conotoxins and predicted their related ion channel receptors. Homologous analysis was also performed for the most abundant ion channel protein, voltage-gated potassium (Kv; with Kv1...
July 18, 2017: Marine Drugs
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