Voltage-gated potassium channels whose primary subunits contain six transmembrane segments and form tetramers to create a pore with a voltage sensor. They are related to their founding member, shaker protein, Drosophila.
Cell membrane glycoproteins that are selectively permeable to potassium ions. At least eight major groups of K channels exist and they are made up of dozens of different subunits.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
A class of drugs that act by inhibition of potassium efflux through cell membranes. Blockade of potassium channels prolongs the duration of ACTION POTENTIALS. They are used as ANTI-ARRHYTHMIA AGENTS and VASODILATOR AGENTS.
Potassium channels where the flow of K+ ions into the cell is greater than the outward flow.
Potassium channel whose permeability to ions is extremely sensitive to the transmembrane potential difference. The opening of these channels is induced by the membrane depolarization of the ACTION POTENTIAL.
Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.
The opening and closing of ion channels due to a stimulus. The stimulus can be a change in membrane potential (voltage-gated), drugs or chemical transmitters (ligand-gated), or a mechanical deformation. Gating is thought to involve conformational changes of the ion channel which alters selective permeability.
A delayed rectifier subtype of shaker potassium channels that is the predominant VOLTAGE-GATED POTASSIUM CHANNEL of T-LYMPHOCYTES.
A delayed rectifier subtype of shaker potassium channels that is selectively inhibited by a variety of SCORPION VENOMS.
A delayed rectifier subtype of shaker potassium channels that is commonly mutated in human episodic ATAXIA and MYOKYMIA.
Potassium channels whose activation is dependent on intracellular calcium concentrations.
Voltage-dependent cell membrane glycoproteins selectively permeable to calcium ions. They are categorized as L-, T-, N-, P-, Q-, and R-types based on the activation and inactivation kinetics, ion specificity, and sensitivity to drugs and toxins. The L- and T-types are present throughout the cardiovascular and central nervous systems and the N-, P-, Q-, & R-types are located in neuronal tissue.
A shaker subfamily that is prominently expressed in NEURONS and are necessary for high-frequency, repetitive firing of ACTION POTENTIALS.
A family of voltage-gated potassium channels that are characterized by long N-terminal and C-terminal intracellular tails. They are named from the Drosophila protein whose mutation causes abnormal leg shaking under ether anesthesia. Their activation kinetics are dependent on extracellular MAGNESIUM and PROTON concentration.
A voltage-gated potassium channel that is expressed primarily in the HEART.
A delayed rectifier subtype of shaker potassium channels that conducts a delayed rectifier current. It contributes to ACTION POTENTIAL repolarization of MYOCYTES in HEART ATRIA.
A subfamily of shaker potassium channels that shares homology with its founding member, Shab protein, Drosophila. They regulate delayed rectifier currents in the NERVOUS SYSTEM of DROSOPHILA and in the SKELETAL MUSCLE and HEART of VERTEBRATES.
A family of delayed rectifier voltage-gated potassium channels that share homology with their founding member, KCNQ1 PROTEIN. KCNQ potassium channels have been implicated in a variety of diseases including LONG QT SYNDROME; DEAFNESS; and EPILEPSY.
A fast inactivating subtype of shaker potassium channels that contains two inactivation domains at its N terminus.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
A major class of calcium activated potassium channels whose members are voltage-dependent. MaxiK channels are activated by either membrane depolarization or an increase in intracellular Ca(2+). They are key regulators of calcium and electrical signaling in a variety of tissues.
Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).
A shaker subfamily of potassium channels that participate in transient outward potassium currents by activating at subthreshold MEMBRANE POTENTIALS, inactivating rapidly, and recovering from inactivation quickly.
Heteromultimers of Kir6 channels (the pore portion) and sulfonylurea receptor (the regulatory portion) which affect function of the HEART; PANCREATIC BETA CELLS; and KIDNEY COLLECTING DUCTS. KATP channel blockers include GLIBENCLAMIDE and mitiglinide whereas openers include CROMAKALIM and minoxidil sulfate.
A very slow opening and closing voltage-gated potassium channel that is expressed in NEURONS and is commonly mutated in BENIGN FAMILIAL NEONATAL CONVULSIONS.
The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.
An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.
Potassium channels that contain two pores in tandem. They are responsible for baseline or leak currents and may be the most numerous of all K channels.
The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
A very slow opening and closing voltage-gated potassium channel that is expressed in NEURONS and is closely related to KCNQ2 POTASSIUM CHANNEL. It is commonly mutated in BENIGN FAMILIAL NEONATAL CONVULSIONS.
A potassium-selective ion channel blocker. (From J Gen Phys 1994;104(1):173-90)
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A class of drugs that act by selective inhibition of calcium influx through cellular membranes.
A group of slow opening and closing voltage-gated potassium channels. Because of their delayed activation kinetics they play an important role in controlling ACTION POTENTIAL duration.
An aquatic genus of the family, Pipidae, occurring in Africa and distinguished by having black horny claws on three inner hind toes.
The ability of a substrate to allow the passage of ELECTRONS.
A family of inwardly-rectifying potassium channels that are activated by PERTUSSIS TOXIN sensitive G-PROTEIN-COUPLED RECEPTORS. GIRK potassium channels are primarily activated by the complex of GTP-BINDING PROTEIN BETA SUBUNITS and GTP-BINDING PROTEIN GAMMA SUBUNITS.
A major class of calcium-activated potassium channels that are found primarily in excitable CELLS. They play important roles in the transmission of ACTION POTENTIALS and generate a long-lasting hyperpolarization known as the slow afterhyperpolarization.
Cell membrane glycoproteins that form channels to selectively pass chloride ions. Nonselective blockers include FENAMATES; ETHACRYNIC ACID; and TAMOXIFEN.
Venoms from animals of the order Scorpionida of the class Arachnida. They contain neuro- and hemotoxins, enzymes, and various other factors that may release acetylcholine and catecholamines from nerve endings. Of the several protein toxins that have been characterized, most are immunogenic.
An antidiabetic sulfonylurea derivative with actions similar to those of chlorpropamide.
A 37-amino acid residue peptide isolated from the scorpion Leiurus quinquestriatus hebraeus. It is a neurotoxin that inhibits calcium activated potassium channels.
One of the POTASSIUM CHANNEL BLOCKERS, with secondary effect on calcium currents, which is used mainly as a research tool and to characterize channel subtypes.
Long-lasting voltage-gated CALCIUM CHANNELS found in both excitable and nonexcitable tissue. They are responsible for normal myocardial and vascular smooth muscle contractility. Five subunits (alpha-1, alpha-2, beta, gamma, and delta) make up the L-type channel. The alpha-1 subunit is the binding site for calcium-based antagonists. Dihydropyridine-based calcium antagonists are used as markers for these binding sites.
The rate dynamics in chemical or physical systems.
A major class of calcium-activated potassium channels that were originally discovered in ERYTHROCYTES. They are found primarily in non-excitable CELLS and set up electrical gradients for PASSIVE ION TRANSPORT.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
The pore-forming subunits of large-conductance calcium-activated potassium channels. They form tetramers in CELL MEMBRANES.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A potassium-channel opening vasodilator that has been investigated in the management of hypertension. It has also been tried in patients with asthma. (Martindale, The Extra Pharmacopoeia, 30th ed, p352)
A guanidine that opens POTASSIUM CHANNELS producing direct peripheral vasodilatation of the ARTERIOLES. It reduces BLOOD PRESSURE and peripheral resistance and produces fluid retention. (Martindale The Extra Pharmacopoeia, 31st ed)
An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.
Potassium or potassium compounds used in foods or as foods.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
A class of drugs that act by inhibition of sodium influx through cell membranes. Blockade of sodium channels slows the rate and amplitude of initial rapid depolarization, reduces cell excitability, and reduces conduction velocity.
Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.
ATP-BINDING CASSETTE PROTEINS that are highly conserved and widely expressed in nature. They form an integral part of the ATP-sensitive potassium channel complex which has two intracellular nucleotide folds that bind to sulfonylureas and their analogs.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Arthropods of the order Scorpiones, of which 1500 to 2000 species have been described. The most common live in tropical or subtropical areas. They are nocturnal and feed principally on insects and other arthropods. They are large arachnids but do not attack man spontaneously. They have a venomous sting. Their medical significance varies considerably and is dependent on their habits and venom potency rather than on their size. At most, the sting is equivalent to that of a hornet but certain species possess a highly toxic venom potentially fatal to humans. (From Dorland, 27th ed; Smith, Insects and Other Arthropods of Medical Importance, 1973, p417; Barnes, Invertebrate Zoology, 5th ed, p503)
CALCIUM CHANNELS that are concentrated in neural tissue. Omega toxins inhibit the actions of these channels by altering their voltage dependence.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Inorganic compounds that contain barium as an integral part of the molecule.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
A condition due to decreased dietary intake of potassium, as in starvation or failure to administer in intravenous solutions, or to gastrointestinal loss in diarrhea, chronic laxative abuse, vomiting, gastric suction, or bowel diversion. Severe potassium deficiency may produce muscular weakness and lead to paralysis and respiratory failure. Muscular malfunction may result in hypoventilation, paralytic ileus, hypotension, muscle twitches, tetany, and rhabomyolysis. Nephropathy from potassium deficit impairs the concentrating mechanism, producing POLYURIA and decreased maximal urinary concentrating ability with secondary POLYDIPSIA. (Merck Manual, 16th ed)
Established cell cultures that have the potential to propagate indefinitely.
Venoms from snakes of the family Elapidae, including cobras, kraits, mambas, coral, tiger, and Australian snakes. The venoms contain polypeptide toxins of various kinds, cytolytic, hemolytic, and neurotoxic factors, but fewer enzymes than viper or crotalid venoms. Many of the toxins have been characterized.
The relationship between the dose of an administered drug and the response of the organism to the drug.
Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.
A subgroup of TRP cation channels that contain 3-4 ANKYRIN REPEAT DOMAINS and a conserved C-terminal domain. Members are highly expressed in the CENTRAL NERVOUS SYSTEM. Selectivity for calcium over sodium ranges from 0.5 to 10.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.
Inorganic compounds that contain potassium as an integral part of the molecule.
A subgroup of cyclic nucleotide-regulated ION CHANNELS within the superfamily of pore-loop cation channels. They are expressed in OLFACTORY NERVE cilia and in PHOTORECEPTOR CELLS and some PLANTS.
A heterogenous group of transient or low voltage activated type CALCIUM CHANNELS. They are found in cardiac myocyte membranes, the sinoatrial node, Purkinje cells of the heart and the central nervous system.
A member of the alkali metals. It has an atomic symbol Cs, atomic number 50, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.
Compounds with a core of fused benzo-pyran rings.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A highly neurotoxic polypeptide from the venom of the honey bee (Apis mellifera). It consists of 18 amino acids with two disulfide bridges and causes hyperexcitability resulting in convulsions and respiratory paralysis.
The regulatory subunits of large-conductance calcium-activated potassium channels.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Proteins that bind specific drugs with high affinity and trigger intracellular changes influencing the behavior of cells. Drug receptors are generally thought to be receptors for some endogenous substance not otherwise specified.
Agents that increase calcium influx into calcium channels of excitable tissues. This causes vasoconstriction in VASCULAR SMOOTH MUSCLE and/or CARDIAC MUSCLE cells as well as stimulation of insulin release from pancreatic islets. Therefore, tissue-selective calcium agonists have the potential to combat cardiac failure and endocrinological disorders. They have been used primarily in experimental studies in cell and tissue culture.
The study of PHYSICAL PHENOMENA and PHYSICAL PROCESSES as applied to living things.
An element that is an alkali metal. It has an atomic symbol Rb, atomic number 37, and atomic weight 85.47. It is used as a chemical reagent and in the manufacture of photoelectric cells.
A derivative of the NIACINAMIDE that is structurally combined with an organic nitrate. It is a potassium-channel opener that causes vasodilatation of arterioles and large coronary arteries. Its nitrate-like properties produce venous vasodilation through stimulation of guanylate cyclase.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
Proteins prepared by recombinant DNA technology.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A family of proton-gated sodium channels that are primarily expressed in neuronal tissue. They are AMILORIDE-sensitive and are implicated in the signaling of a variety of neurological stimuli, most notably that of pain in response to acidic conditions.
Sodium channels found on salt-reabsorbing EPITHELIAL CELLS that line the distal NEPHRON; the distal COLON; SALIVARY DUCTS; SWEAT GLANDS; and the LUNG. They are AMILORIDE-sensitive and play a critical role in the control of sodium balance, BLOOD VOLUME, and BLOOD PRESSURE.
A subgroup of TRP cation channels named after melastatin protein. They have the TRP domain but lack ANKYRIN repeats. Enzyme domains in the C-terminus leads to them being called chanzymes.
CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
A benzothiadiazine derivative that is a peripheral vasodilator used for hypertensive emergencies. It lacks diuretic effect, apparently because it lacks a sulfonamide group.
A subgroup of TRP cation channels named after vanilloid receptor. They are very sensitive to TEMPERATURE and hot spicy food and CAPSAICIN. They have the TRP domain and ANKYRIN repeats. Selectivity for CALCIUM over SODIUM ranges from 3 to 100 fold.
The physical characteristics and processes of biological systems.
Stable potassium atoms that have the same atomic number as the element potassium, but differ in atomic weight. K-41 is a stable potassium isotope.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
10-carbon saturated monocarboxylic acids.
Organic compounds containing both the hydroxyl and carboxyl radicals.
An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Synthetic transcripts of a specific DNA molecule or fragment, made by an in vitro transcription system. This cRNA can be labeled with radioactive uracil and then used as a probe. (King & Stansfield, A Dictionary of Genetics, 4th ed)
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Elements of limited time intervals, contributing to particular results or situations.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
A delayed rectifier subtype of shaker potassium channels that has been described in NEURONS and ASTROCYTES.
A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.
Unstable isotopes of potassium that decay or disintegrate emitting radiation. K atoms with atomic weights 37, 38, 40, and 42-45 are radioactive potassium isotopes.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Use of electric potential or currents to elicit biological responses.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
A family of neuronal calcium-sensor proteins that interact with and regulate potassium channels, type A.
The class of true jellyfish, in the phylum CNIDARIA. They are mostly free-swimming marine organisms that go through five stages in their life cycle and exhibit two body forms: polyp and medusa.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
A broad group of eukaryotic six-transmembrane cation channels that are classified by sequence homology because their functional involvement with SENSATION is varied. They have only weak voltage sensitivity and ion selectivity. They are named after a DROSOPHILA mutant that displayed transient receptor potentials in response to light. A 25-amino-acid motif containing a TRP box (EWKFAR) just C-terminal to S6 is found in TRPC, TRPV and TRPM subgroups. ANKYRIN repeats are found in TRPC, TRPV & TRPN subgroups. Some are functionally associated with TYROSINE KINASE or TYPE C PHOSPHOLIPASES.
Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.
Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.
A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.
An actinomycete used for production of commercial ANTIBIOTICS and as a host for gene cloning.
A condition that is characterized by episodes of fainting (SYNCOPE) and varying degree of ventricular arrhythmia as indicated by the prolonged QT interval. The inherited forms are caused by mutation of genes encoding cardiac ion channel proteins. The two major forms are ROMANO-WARD SYNDROME and JERVELL-LANGE NIELSEN SYNDROME.
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
Drugs used to cause dilation of the blood vessels.
Peptide neurotoxins from the marine fish-hunting snails of the genus CONUS. They contain 13 to 29 amino acids which are strongly basic and are highly cross-linked by disulfide bonds. There are three types of conotoxins, omega-, alpha-, and mu-. OMEGA-CONOTOXINS inhibit voltage-activated entry of calcium into the presynaptic membrane and therefore the release of ACETYLCHOLINE. Alpha-conotoxins inhibit the postsynaptic acetylcholine receptor. Mu-conotoxins prevent the generation of muscle action potentials. (From Concise Encyclopedia Biochemistry and Molecular Biology, 3rd ed)
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.
Pyridines substituted in any position with an amino group. May be hydrogenated, but must retain at least one double bond.
Membrane proteins whose primary function is to facilitate the transport of positively charged molecules (cations) across a biological membrane.
CALCIUM CHANNELS located within the PURKINJE CELLS of the cerebellum. They are involved in stimulation-secretion coupling of neurons.
The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)
A group of compounds that are monomethyl derivatives of pyridines. (From Dorland, 28th ed)
A potent direct-acting peripheral vasodilator (VASODILATOR AGENTS) that reduces peripheral resistance and produces a fall in BLOOD PRESSURE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p371)
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
An aminoperhydroquinazoline poison found mainly in the liver and ovaries of fishes in the order TETRAODONTIFORMES, which are eaten. The toxin causes paresthesia and paralysis through interference with neuromuscular conduction.
A superorder of CEPHALOPODS comprised of squid, cuttlefish, and their relatives. Their distinguishing feature is the modification of their fourth pair of arms into tentacles, resulting in 10 limbs.
A genus of the family Muridae consisting of eleven species. C. migratorius, the grey or Armenian hamster, and C. griseus, the Chinese hamster, are the two species used in biomedical research.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
A subgroup of cyclic nucleotide-regulated ION CHANNELS of the superfamily of pore-loop cation channels that are opened by hyperpolarization rather than depolarization. The ion conducting pore passes SODIUM, CALCIUM, and POTASSIUM cations with a preference for potassium.
Layers of lipid molecules which are two molecules thick. Bilayer systems are frequently studied as models of biological membranes.
Abnormally low potassium concentration in the blood. It may result from potassium loss by renal secretion or by the gastrointestinal route, as by vomiting or diarrhea. It may be manifested clinically by neuromuscular disorders ranging from weakness to paralysis, by electrocardiographic abnormalities (depression of the T wave and elevation of the U wave), by renal disease, and by gastrointestinal disorders. (Dorland, 27th ed)
An inorganic compound that is used as a source of iodine in thyrotoxic crisis and in the preparation of thyrotoxic patients for thyroidectomy. (From Dorland, 27th ed)
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.
The hollow, muscular organ that maintains the circulation of the blood.
The accumulation of an electric charge on a object
Toxic substances from microorganisms, plants or animals that interfere with the functions of the nervous system. Most venoms contain neurotoxic substances. Myotoxins are included in this concept.
Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.
Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.
An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.
A voltage-gated sodium channel subtype that mediates the sodium ion PERMEABILITY of CARDIOMYOCYTES. Defects in the SCN5A gene, which codes for the alpha subunit of this sodium channel, are associated with a variety of CARDIAC DISEASES that result from loss of sodium channel function.
CALCIUM CHANNELS located in the neurons of the brain.
Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade.
The nonstriated involuntary muscle tissue of blood vessels.
A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.
A sulphonylurea hypoglycemic agent with actions and uses similar to those of CHLORPROPAMIDE. (From Martindale, The Extra Pharmacopoeia, 30th ed, p290)
The relationships of groups of organisms as reflected by their genetic makeup.
Venoms from jellyfish; CORALS; SEA ANEMONES; etc. They contain hemo-, cardio-, dermo- , and neuro-toxic substances and probably ENZYMES. They include palytoxin, sarcophine, and anthopleurine.
A potent vasodilator agent with calcium antagonistic action. It is a useful anti-anginal agent that also lowers blood pressure.
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
The electrical properties, characteristics of living organisms, and the processes of organisms or their parts that are involved in generating and responding to electrical charges.
Unstable isotopes of rubidium that decay or disintegrate emitting radiation. Rb atoms with atomic weights 79-84, and 86-95 are radioactive rubidium isotopes.
A tetrameric calcium release channel in the SARCOPLASMIC RETICULUM membrane of SMOOTH MUSCLE CELLS, acting oppositely to SARCOPLASMIC RETICULUM CALCIUM-TRANSPORTING ATPASES. It is important in skeletal and cardiac excitation-contraction coupling and studied by using RYANODINE. Abnormalities are implicated in CARDIAC ARRHYTHMIAS and MUSCULAR DISEASES.
Venoms from mollusks, including CONUS and OCTOPUS species. The venoms contain proteins, enzymes, choline derivatives, slow-reacting substances, and several characterized polypeptide toxins that affect the nervous system. Mollusk venoms include cephalotoxin, venerupin, maculotoxin, surugatoxin, conotoxins, and murexine.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
Positively charged atoms, radicals or group of atoms with a valence of plus 1, which travel to the cathode or negative pole during electrolysis.
Contractile tissue that produces movement in animals.
Mice which carry mutant genes for neurologic defects or abnormalities.
An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.
The characteristic 3-dimensional shape and arrangement of multimeric proteins (aggregates of more than one polypeptide chain).
Proteins found in any species of bacterium.
Different forms of a protein that may be produced from different GENES, or from the same gene by ALTERNATIVE SPLICING.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.
A voltage-gated sodium channel subtype that mediates the sodium ion permeability of excitable membranes. Defects in the SCN2A gene which codes for the alpha subunit of this sodium channel are associated with benign familial infantile seizures type 3, and early infantile epileptic encephalopathy type 11.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.

Mutations in the S4 region isolate the final voltage-dependent cooperative step in potassium channel activation. (1/462)

Charged residues in the S4 transmembrane segment play a key role in determining the sensitivity of voltage-gated ion channels to changes in voltage across the cell membrane. However, cooperative interactions between subunits also affect the voltage dependence of channel opening, and these interactions can be altered by making substitutions at uncharged residues in the S4 region. We have studied the activation of two mutant Shaker channels that have different S4 amino acid sequences, ILT (V369I, I372L, and S376T) and Shaw S4 (the S4 of Drosophila Shaw substituted into Shaker), and yet have very similar ionic current properties. Both mutations affect cooperativity, making a cooperative transition in the activation pathway rate limiting and shifting it to very positive voltages, but analysis of gating and ionic current recordings reveals that the ILT and Shaw S4 mutant channels have different activation pathways. Analysis of gating currents suggests that the dominant effect of the ILT mutation is to make the final cooperative transition to the open state of the channel rate limiting in an activation pathway that otherwise resembles that of Shaker. The charge movement associated with the final gating transition in ILT activation can be measured as an isolated component of charge movement in the voltage range of channel opening and accounts for 13% ( approximately 1.8 e0) of the total charge moved in the ILT activation pathway. The remainder of the ILT gating charge (87%) moves at negative voltages, where channels do not open, and confirms the presence of Shaker-like conformational changes between closed states in the activation pathway. In contrast to ILT, the activation pathway of Shaw S4 seems to involve a single cooperative charge-moving step between a closed and an open state. We cannot detect any voltage-dependent transitions between closed states for Shaw S4. Restoring basic residues that are missing in Shaw S4 (R1, R2, and K7) rescues charge movement between closed states in the activation pathway, but does not alter the voltage dependence of the rate-limiting transition in activation.  (+info)

Helical structure and packing orientation of the S2 segment in the Shaker K+ channel. (2/462)

Six transmembrane segments, S1-S6, cluster around the central pore-forming region in voltage-gated K+ channels. To investigate the structural characteristics of the S2 segment in the Shaker K+ channel, we replaced each residue in S2 singly with tryptophan (or with alanine for the native tryptophan). All but one of the 23 Trp mutants expressed voltage-dependent K+ currents in Xenopus oocytes. The effects of the mutations were classified as being of low or high impact on channel gating properties. The periodicity evident in the effects of these mutations supports an alpha-helical structure for the S2 segment. The high- and low-impact residues cluster onto opposite faces of a helical wheel projection of the S2 segment. The low-impact face is also tolerant of single mutations to asparagine. All results are consistent with the idea that the low-impact face projects toward membrane lipids and that changes in S2 packing occur upon channel opening. We conclude that the S2 segment is a transmembrane alpha helix and that the high-impact face packs against other transmembrane segments in the functional channel.  (+info)

Overexpression of a Shaker-type potassium channel in mammalian central nervous system dysregulates native potassium channel gene expression. (3/462)

The nervous system maintains a delicate balance between excitation and inhibition, partly through the complex interplay between voltage-gated sodium and potassium ion channels. Because K+ channel blockade or gene deletion causes hyperexcitability, it is generally assumed that increases in K+ channel gene expression should reduce neuronal network excitability. We have tested this hypothesis by creating a transgenic mouse that expresses a Shaker-type K+ channel gene. Paradoxically, we find that addition of the extra K+ channel gene results in a hyperexcitable rather than a hypoexcitable phenotype. The presence of the transgene leads to a complex deregulation of endogenous Shaker genes in the adult central nervous system as well as an increase in network excitability that includes spontaneous cortical spike and wave discharges and a lower threshold for epileptiform bursting in isolated hippocampal slices. These data suggest that an increase in K+ channel gene dosage leads to dysregulation of normal K+ channel gene expression, and it may underlie a mechanism contributing to the pathogenesis of human aneuploidies such as Down syndrome.  (+info)

Molecular modeling of voltage-gated potassium channel pore. (4/462)

AIM: To build a structure model for the pore of voltage-gated Shaker potassium channel and examine its validity. METHODS: (1) Structural restraints were derived from experimental and theoretical studies; (2) An initial structural motif satisfying the derived restraints was first constructed, and further refined by restrained molecular mechanics; (3) The quality of the model was judged by the criterion that whether it could clarify molecular mechanisms of channel functions and explain the known experimental facts. RESULTS: (1) A computer pore structure was proposed, in which the residues within signature sequence (corresponding to Shaker 439-446) dipped into the membrane and formed the narrow part of the pore in a non-periodic conformation, while the other residues in the P region constituted the outer mouth of the pore; (2) The ion selectivity was achieved through cation-pi orbital interaction mechanism at position 445 and oxygen cage mechanism at position 447; (3) Different binding modes led to different affinity of CTX and AgTx2 to channel; and (4) The inside of pore was dominated by negative electrostatic potential. CONCLUSION: The model proposed was consistent with the derived restraints from the experimental results.  (+info)

IA in Kenyon cells of the mushroom body of honeybees resembles shaker currents: kinetics, modulation by K+, and simulation. (5/462)

Cultured Kenyon cells from the mushroom body of the honeybee, Apis mellifera, show a voltage-gated, fast transient K+ current that is sensitive to 4-aminopyridine, an A current. The kinetic properties of this A current and its modulation by extracellular K+ ions were investigated in vitro with the whole cell patch-clamp technique. The A current was isolated from other voltage-gated currents either pharmacologically or with suitable voltage-clamp protocols. Hodgkin- and Huxley-style mathematical equations were used for the description of this current and for the simulation of action potentials in a Kenyon cell model. Activation and inactivation of the A current are fast and voltage dependent with time constants of 0.4 +/- 0.1 ms (means +/- SE) at +45 mV and 3.0 +/- 1.6 ms at +45 mV, respectively. The pronounced voltage dependence of the inactivation kinetics indicates that at least a part of this current of the honeybee Kenyon cells is a shaker-like current. Deactivation and recovery from inactivation also show voltage dependency. The time constant of deactivation has a value of 0.4 +/- 0.1 ms at -75 mV. Recovery from inactivation needs a double-exponential function to be fitted adequately; the resulting time constants are 18 +/- 3.1 ms for the fast and 745 +/- 107 ms for the slow process at -75 mV. Half-maximal activation of the A current occurs at -0.7 +/- 2.9 mV, and half-maximal inactivation occurs at -54.7 +/- 2.4 mV. An increase in the extracellular K+ concentration increases the conductance and accelerates the recovery from inactivation of the A current, affecting the slow but not the fast time constant. With respect to these modulations the current under investigation resembles some of the shaker-like currents. The data of the A current were incorporated into a reduced computational model of the voltage-gated currents of Kenyon cells. In addition, the model contained a delayed rectifier K+ current, a Na+ current, and a leakage current. The model is able to generate an action potential on current injection. The model predicts that the A current causes repolarization of the action potential but not a delay in the initiation of the action potential. It further predicts that the activation of the delayed rectifier K+ current is too slow to contribute markedly to repolarization during a single action potential. Because of its fast activation, the A current reduces the amplitude of the net depolarizing current and thus reduces the peak amplitude and the duration of the action potential.  (+info)

The effects of level of expression of a jellyfish Shaker potassium channel: a positive potassium feedback mechanism. (6/462)

1. When jellyfish Shaker potassium channels (jShak2) are heterologously expressed in Xenopus oocytes at different levels they demonstrate density-dependent changes in electrical and kinetic properties of macroscopic currents. 2. The activation and inactivation properties of jShak2 channels depend on the extracellular potassium concentration. In this study we present experimental data which show that expression-dependent changes in kinetic and electrical properties of jShak2 macroscopic currents can be explained by the positive feedback effect of dynamic accumulation of K+ in the perimembranal space.  (+info)

Auxiliary Hyperkinetic beta subunit of K+ channels: regulation of firing properties and K+ currents in Drosophila neurons. (7/462)

Auxiliary Hyperkinetic beta subunit of K+ channels: regulation of firing properties and K+ currents in Drosophila neurons. Molecular analysis and heterologous expression have shown that K+ channel beta subunits regulate the properties of the pore-forming alpha subunits, although how they influence neuronal K+ currents and excitability remains to be explored. We studied cultured Drosophila "giant" neurons derived from mutants of the Hyperkinetic (Hk) gene, which codes for a K+ channel beta subunit. Whole cell patch-clamp recording revealed broadened action potentials and, more strikingly, persistent rhythmic spontaneous activities in a portion of mutant neurons. Voltage-clamp analysis demonstrated extensive alterations in the kinetics and voltage dependence of K+ current activation and inactivation, especially at subthreshold membrane potentials, suggesting a role in regulating the quiescent state of neurons that are capable of tonic firing. Altered sensitivity of Hk currents to classical K+ channel blockers (4-aminopyridine, alpha-dendrotoxin, and TEA) indicated that Hk mutations modify interactions between voltage-activated K+ channels and these pharmacological probes, apparently by changing both the intra- and extracellular regions of the channel pore. Correlation of voltage- and current-clamp data from the same cells indicated that Hk mutations affect not only the persistently active neurons, but also other neuronal categories. Shaker (Sh) mutations, which alter K+ channel alpha subunits, increased neuronal excitability but did not cause the robust spontaneous activity characteristic of some Hk neurons. Significantly, Hk Sh double mutants were indistinguishable from Sh single mutants, implying that the rhythmic Hk firing pattern is conferred by intact Shalpha subunits in a distinct neuronal subpopulation. Our results suggest that alterations in beta subunit regulation, rather than elimination or addition of alpha subunits, may cause striking modifications in the excitability state of neurons, which may be important for complex neuronal function and plasticity.  (+info)

Peptidyl inhibitors of shaker-type Kv1 channels elicit twitches in guinea pig ileum by blocking kv1.1 at enteric nervous system and enhancing acetylcholine release. (8/462)

Potent and selective peptidyl blockers of the Shaker-type (Kv1) voltage-gated potassium channels were used to determine the role of these channels in regulating the spontaneous motility of smooth muscle preparations. Margatoxin (MgTX), kaliotoxin, and agitoxin-2 at 1 to 10 nM and agitoxin-1 at 50 to 100 nM induce twitches in guinea pig ileum strips. These twitches are abolished by tetrodotoxin (TTX, 0.5 microM), atropine (1 microM), hexamethonium (10 microM), or nifedipine (0.1 microM). It is proposed that blockade of Kv1 channels by MgTX, kaliotoxin, or the agitoxins increases excitability of intramural nerve plexuses in the ileum, promoting release of acetylcholine from excitatory motor nerve terminals. This, in turn, leads to Ca2+-dependent action potentials and twitching of the muscle fibers. MgTX does not induce twitches in several other guinea pig and/or rat vascular, genitourinary, or gastrointestinal smooth muscles, although small increases in spontaneous myogenic activity may be seen in detrusor muscle exposed to >30 nM MgTX. This effect is not reversed by TTX or atropine. The TTX- and atropine-sensitive twitches of guinea pig ileum are also induced by nanomolar concentrations of alpha-dendrotoxin, a selective blocker of Shaker Kv1.1 and 1.2 subtypes, or stichodactylatoxin, a peptide isolated from sea anemone that displays high affinity for Kv1.1 and 1.3, but not by charybdotoxin, which blocks Kv1.2 and 1.3 but not 1.1. The data taken together suggest that high-affinity blockade of Kv1.1 underlies the ability of MgTX, kaliotoxin, agitoxin-1, agitoxin-2, alpha-dendrotoxin, and stichodactylatoxin to elicit TTX-sensitive twitches in guinea pig ileum.  (+info)

In this paper, we investigated the interaction of hanatoxin with the Shaker Kv channel. In contrast to the inhibitory actions of the toxin on Kv2.1 channels investigated in previous studies (Swartz and MacKinnon, 1997a,b; Li-Smerin and Swartz, 1998, 2000, 2001; Lee et al., 2003; Wang et al., 2004; Phillips et al., 2005; Alabi et al., 2007; Bosmans et al., 2008), our results show that hanatoxin facilitates opening of the Shaker Kv channel by interacting with the paddle motif (Figs. 1-3), stabilizing the voltage sensor in the activated state (Fig. 5), and influencing the final opening transition to stabilize the open state of the pore (Figs. 4 and 6). Although the effects of hanatoxin on the G-V relations (Figs. 1 and 2), the kinetics of channel closure (Figs. 1 and 4), and the ILT channel (Fig. 6) could in part be explained by effects on the final opening transition in Shaker, the pronounced effects of the toxin on gating currents (Fig. 5) suggest that early transitions in the voltage sensors are ...
Backbench Business. Shaker Aamer. John McDonnell (Hayes and Harlington) (Lab): I beg to move, That this House calls on the US Government to release Shaker Aamer from his imprisonment in Guantánamo Bay and to allow him to return to his family in the UK.. I thank the Backbench Business Committee for allocating time for this critical debate at an important time in the campaign to secure the release of Shaker Aamer. By way of introduction, I pay tribute to all those who have campaigned so hard over many years to bring Shaker Aamers case to our attention. I pay tribute to the Save Shaker Aamer Campaign, and all those campaigners who have stood in Parliament Square month after month protesting in their orange boiler suits with their placards until someone began to listen to them. I pay tribute to the We Stand with Shaker campaign, to Shakers family who have joined us today and to the organisations Reprieve and Amnesty International. I pay tribute, too, to the full range of newspapers that ...
Previous studies on the interaction between the inactivating peptide of the Shaker B K+ channel (ShB peptide, H2N-MAAVAGLYGLGEDRQHRKKQ) and anionic phospholipid vesicles, used as model targets, have shown that the ShB peptide: (i) binds to the vesicle surface with high affinity; (ii) readily adopts a strongly hydrogen-bonded β-structure; and (iii) becomes inserted into the hydrophobic bilayer. We now report fluorescence studies showing that the vesicle-inserted ShB peptide is in a monomeric form and, therefore, the observed β-structure must be intramolecularly hydrogen-bonded to produce a β-hairpin conformation. Also, additional freeze-fracture and accessibility-to-trypsin studies, which aimed to estimate how deeply and in which orientation the folded monomeric peptide inserts into the model target, have allowed us to build structural models for the target-inserted peptide. In such models, the peptide has been folded near G6 to configure a long β-hairpin modelled to produce an internal ...
Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. Their diverse functions include regulating neurotransmitter release, heart rate, insulin secretion, neuronal excitability, epithelial electrolyte transport, smooth muscle contraction, and cell volume. Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has been shown to have human homolog(s). This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. This member contains six membrane-spanning domains with a shaker-type repeat in the fourth segment. It belongs to the delayed rectifier class, members of which allow nerve cells to efficiently repolarize following an action potential. It plays an essential role in T-cell proliferation and activation. This gene appears to be intronless and it is clustered together with KCNA2 and KCNA10 genes on chromosome 1.
1989 by the National Academy of Sciences. Contributed by N. Davidson, July 14, 1989. We thank Barbara Thorne for expert assistance in the construction of the recombinant virus and J.H. Strauss and R.W. Aldrich for advice. Charybdotoxin was a generous gift of Dr. M.L. Garcia (Merck Sharp & Dohme Research Laboratories). This work was supported by National Institutes of Health Grants GM10991, GM29836, and DK37274, by the Cystic Fibrosis Foundation, and by fellowships from the Max Kade Foundation (A.K.) and the National Institutes of Health (R.J.L.). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. §1734 solely to indicate this fact ...
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The equilibrium of voltage sensors between resting and activated states, as reflected in the gating charge (Q) versus voltage (V) relation, is sensitive to the initial voltage from which gating currents are elicited. For example, in a variety of voltage-activated channels and the Ci-VSP voltage-sensitive phosphatase, Q-V relations exhibit a pronounced shift to negative voltages when gating currents are elicited from positive voltages (Bezanilla et al., 1982; Olcese et al., 1997; Villalba-Galea et al., 2008). Villalba-Galea et al. (2008) have proposed that prolonged activation of voltage sensors at positive voltages causes them to shift into a relaxed state, and that the crystal structures of Kv channels represent this relaxed state rather than the activated state. Our constraints with bridges between S4 in both pre-open and open states are compatible with the crystal structure of the Kv1.2 paddle chimera, as discussed above, suggesting that the structural differences between activated and ...
Tujuan : Mengetahui hubungan antara temuan klinis ( skor Alvarado ) dengan temuan operasi jaringan appendik pada kasus appendisitis akut dewasa. Latar belakang : Diagnosa appendisitis akut tidak mudah ditegakkan hanya berdasarkan gambaran klinis. Keadaan ini menghasilkan angka appendektomi negatif sebesar 20% dan angka perforasi sebesar 20-30%. Salah satu upaya meningkatkan kualitas dan kuantitas pelayanan medis ialah membuat diagnosa yang tepat. Telah banyak dikemukakan cara untuk menurunkan insidensi appendektomi negatif, salah satunya adalah dengan instrumen skor Alvarado. Skor Alvarado adalah sistem skoring sederhana yang bisa dilakukan dengan mudah, cepat, dan kurang invasif. Morbiditas dan mortalitas appendisitis akut masih cukup tinggi. Hal ini disebabkan keterlambatan diagnosa dan penanganan pembedahan. Pembedahan yang terlambat mungkin tetap berhubungan dengan perforasi. Sebagian besar penderita dengan risiko appendisitis perforasi mempunyai skor Alvarado yang tinggi. Tujuan dari ...
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CHARLES MINER, a well known member of the North Family Shakers, Enfield, N. H. committed suicide sometime during Monday night, on May 1st, shooting himself through the head with a small rifle, in his room, at Shaker Village. He was about 62 years of age. This Spring he had charge of the sugar camp and to the many who visited him there, [he] seemed to be social and happy, but at other times he has shown signs of being a little out. Lately he talked of leaving the Shakers, and only the P.M. before he shot himself, he was over in the village at North Enfield, endeavoring to obtain employ. His dead body was discovered in his room, on Tuesday morning, the rifle by his side. ...
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Kv1.2 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is selectively inhibited by a variety of SCORPION VENOMS.
Kv1.1 Potassium Channel: A delayed rectifier subtype of shaker potassium channels that is commonly mutated in human episodic ATAXIA and MYOKYMIA.
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Phosphatidic acid influences the gating of voltage-gated K+ channels through a non-specific surface charge mechanism and through a specific interaction between a voltage sensor arginine and the primary phosphate head group on the cytoplasmic membrane leaflet.
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TIP: Adjust the intensity of your Gold Standard 100% Whey™ by varying the amount of liquid that you use to prepare it. For a bolder flavor with slightly more body and sweetness, mix each scoop with 4-6 oz of water, milk, or your favorite beverage. For a milder tasting, less sweet shake, use 8-10 oz of liquid per scoop.. SHAKER: Bringing a shaker cup with you to the gym is the best way to get a powerful dose of protein immediately after your workout. Just pour in 6-8 oz of your preferred beverage and then add one rounded scoop of Gold Standard 100% Whey™ to your shaker cup. Cover and shake for 25-30 seconds. Dont have a shaker cup? Pick yourself up one of our Shaker Bottles. Click Here!. SUGGESTED USE: Consume approximately 1 gram of protein per pound of body weight per day through a combination of high protein foods and protein supplements. For even best results, consume your daily protein allotment over several small meals spread evenly throughout the day.. BLENDER: Add one rounded scoop ...
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Ahojky, tak ja sa pripojim :) Ja mam rovnakeho priatela ako Ty - v urcitom smere. On sice za mnou chodi pravidelne, sme spolu ale uz par rokov, ale nebolo to vzdy rovnake - najskor sme sa spolu stretavali vonku, potom chodil on za mnou a ja k nemu este nie, pak ja k nemu viackrat za tyzden a on menej krat za mnou, teraz zasa chodi viacmenej on ku mne a spolocne id. k nim k jeho rod. na navstevu, proste ako nam to vyhovuje kvoli ostatnym veciam - praci a podobne. Zalezi, ako ste spolu dlho. My v tomto problem nemame, skor je problem v tom, ze on aj podla znamenia na nom sedi, ze je skor taky domased a ja skor spolocenska.. tak skor bol problem, ako travit vikend, ked mame volno. Zo zaciatku sme samozrejme spolu podnikali vela veci, casom sa to otupilo, uz si bol asi mnou isty :-), tak sa nesnazil az tak - pretoze to nie je jeho prirodzena stranka.. No a tu som nastupila ja - kdezto on to neprijimal moc pozitivne moje navrhy chodit niekam von (do prirody, na vylety a pod.), takze sme vsetko ...
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AbstrakPerubahan gambaran elektrokardiogram (EKG) terjadi pada fase akut IMA EST baik berupa perubahan repolarisasi ataupun perubahan depolarisasi. Skor QRS Selvester dan pemanjangan kompleks QRS merupakan parameter yang digunakan untuk memperkirakan luas infark dan penilaian iskemia. Tujuan penulisan ini adalah untuk mengetahui mekanisme perubahan durasi QRS dan skor QRS Selvester setelah reperfusi yang optimal. Penulisan artikel ini berdasarkan studi kepustakaan yang terkait dengan peranan durasi QRS dan skor QRS Selvester serta keberhasilan reperfusi miokard. Iskemia mengakibatkan perubahan gambaran listrik sel miokard normal, sehingga terjadi perubahan gambaran EKG yaitu meliputi perubahan gelombang T, elevasi segmen ST dan distorsi dengan pemanjangan kompleks QRS. Penilaian luas infark dapat dilakukan dengan menilai skor QRS Selvester. Iskemia juga mengakibatkan pemanjangan kompleks QRS melalui pemanjangan konduksi purkinye dan blok peri-infark. Reperfusi optimal dapat mengakibatkan regresi ...
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Maurotoxin (MTX) is a 34-residue toxin that was isolated initially from the venom of the scorpion Scorpio maurus palmatus. Unlike the other toxins of the α-KTx6 family (Pi1, Pi4, Pi7, and HsTx1), MTX exhibits a unique disulfide bridge organization of the type C(1) C(5) , C(2) C(6) , C(3) C(4) , and C(7) C(8) (instead of the conventional C(1) C(5) , C(2) C(6) , C(3) C(7) , and C(4) C(8) , herein referred to as Pi1-like) that does not prevent its folding along the classic α/β scaffold of scorpion toxins. MTX(Pi1) is an MTX variant with a conventional pattern of disulfide bridging without any primary structure alteration of the toxin. Here, using MTX and/or MTX(Pi1) as models, we investigated how the type of folding influences toxin recognition of the Shaker B potassium channel. Amino acid residues of MTX that were studied for Shaker B recognition were selected on the basis of their homologous position in charybdotoxin, a three disulfide-bridged scorpion toxin also active on this
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Charybdotoxin occludes the pore of calcium-activated voltage-gated shaker K+ channels by binding to one of four independent, overlapping binding sites.[6][7] It binds both to the open and the closed states. In addition, the block is enhanced as the ionic strength is lowered.[8] This block occurs as the Asn 30 on the CTX interacts with the Asp 381 on the K+ channel.[9] The blockade of K+ channels by the charybdotoxin peptide causes neuronal hyperexcitability. Mutations of the Lys31Gln and the Asn30Gln had the effect of lessening the CTX block of the pore on the shaker channel.[9] ...
Bench-Top Shaker (Voltage 240) [G099A S60024] - Reciprocating shaking and mixing with bench-top convenience is now available. Glas-Cols Bench-Top Shaker is an adaptable, user-friendly shaker that is capable of many hours of continuous hands free shaking and mixing. This shaker features:A variable-speed motor that provides gentle, low-speed shaking to vigorous, high-speed shaking. A built-in shaking head with
White dog shaker syndrome (also known as idiopathic steroid responsive shaker syndrome, shaker dog syndrome and little white shakers syndrome; Latin name Idiopathic Cerebellitis) causes full body tremors in small dog breeds. It is most common in West Highland White Terriers, Maltese, Bichons, and Poodles,[1] and other small dogs. There is a sudden onset of the disease at one to two years of age. It is more likely to occur, and the symptom is worse during times of stress. Nystagmus, difficulty walking, and seizures may occur in some dogs.. The cause is unknown, but it may be mediated by the immune system. One theory is that there is an autoimmune-induced generalized deficiency of neurotransmitters.[2] Cerebrospinal fluid analysis may reveal an increased number of lymphocytes.[3] Treatment with corticosteroids may put the dog into remission, or diazepam may control the symptoms.[4] Typically the two drugs are used together.[5] There is a good prognosis, and symptoms usually resolve with ...
Tonic Studios - Essentials Number Shaker Set - DIE & Blisters No. 7 - 2827E With numbers 0-9 celebrate any milestone occasion from birthdays to anniversaries and so much more. Fill your shaker blister with liquids, glitter, sequins, confetti, sweets, seed peals etc. Set includes 1 Number 7 die and 5 Number 7 shaker blisters for multiple uses. Look out for other die and shaker numbers in the range!
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en] Oligodendrocyte precursor (OP) cells are exposed to multiple extrinsic signals that control their proliferation and differentiation. Previous cell proliferation studies and electrophysiological analysis in cultured cells and in brain slices have suggested that outward potassium channels, particularly Kv1 subunits, may have a prominent role in OP cell proliferation. In the present study, we assessed to what extent overexpression of Kv1.3, Kv1.4, Kv1.5, and Kv1.6 can affect OP cell proliferation and differentiation in culture. We observed that overexpression of Kv1.3 or Kv1.4 increased OP cell proliferation in the absence of mitogens, whereas Kv1.6 overexpression inhibited mitogen-induced OP cell cycle progression. Interestingly, Kv1.3, Kv1.4, Kv1.5, and Kv1.6 overexpression did not interfere with the kinetics of oligodendrocyte differentiation. This study represents the first demonstration that the activity of potassium channels containing distinct Kv1 subunit proteins directly controls ...
Recommended Articles:. Horresh I, Poliak S, Grant S, et al.. 2008. Multiple Molecular Interactions Determine the Clustering of Caspr2 and Kv1 Channels in Myelinated Axons. JOURNAL OF NEUROSCIENCE 28(52): 14213-14222 Goldberg EM, Clark BD, Zagha E, et al.. 2008. K+ channels at the axon initial segment dampen near-threshold excitability of neocortical fast-spiking GABAergic interneurons. NEURON 58 (3): 387-400 Kole MHP, Letzkus JJ, Stuart GJ. 2007. Axon initial segment Kv1 channels control axonal action potential waveform and synaptic efficacy. NEURON 55( 4): 633-647 Gu C, Zhou W, Puthenveedu MA, et al. 2006. The microtubule plus-end tracking protein EB1 is required for Kv1 voltage-gated K+ channel axonal targeting. NEURON 52(5 ): 803-816 Kleopa KA, Elman LB, Lang B, et al. 2006. Neuromyotonia and limbic encephalitis sera target mature Shaker-type K+ channels: subunit specificity correlates with clinical manifestations. BRAIN 129(Part 6):1570-1584 Hasband MN, Park EW, Zhen DK, et al. 2002. ...
Recommended Articles:. Horresh I, Poliak S, Grant S, et al.. 2008. Multiple Molecular Interactions Determine the Clustering of Caspr2 and Kv1 Channels in Myelinated Axons. JOURNAL OF NEUROSCIENCE 28(52): 14213-14222 Goldberg EM, Clark BD, Zagha E, et al.. 2008. K+ channels at the axon initial segment dampen near-threshold excitability of neocortical fast-spiking GABAergic interneurons. NEURON 58 (3): 387-400 Kole MHP, Letzkus JJ, Stuart GJ. 2007. Axon initial segment Kv1 channels control axonal action potential waveform and synaptic efficacy. NEURON 55( 4): 633-647 Gu C, Zhou W, Puthenveedu MA, et al. 2006. The microtubule plus-end tracking protein EB1 is required for Kv1 voltage-gated K+ channel axonal targeting. NEURON 52(5 ): 803-816 Kleopa KA, Elman LB, Lang B, et al. 2006. Neuromyotonia and limbic encephalitis sera target mature Shaker-type K+ channels: subunit specificity correlates with clinical manifestations. BRAIN 129(Part 6):1570-1584 Hasband MN, Park EW, Zhen DK, et al. 2002. ...
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Grapevine (Vitisvinifera L.), one of the most important fruit crops, is a model plant for studying the physiology of fleshy fruits. Here, we report on the characterization of a new grapevine Shaker-type K+ channel, VvK5.1. Phylogenetic analysis revealed that VvK5.1 belongs to the SKOR-like subfamily. Our functional characterization of VvK5.1 in Xenopus oocytes confirms that it is an outwardly rectifying K+ channel that displays strict K+ selectivity. Gene expression level analyses by RT-qPCR showed that the VvK5.1 expression was detected in berries, roots, and flowers. In contrast to its Arabidopsis thaliana counterpart that is involved in K+ secretion in the root pericycle, allowing root-to-shoot K+ translocation, VvK5.1 expression territory is strongly enlarged. We showed by in situ hybridization that VvK5.1 is expressed in the phloem and perivascular cells of berries and in flower pistil. In the root, in addition to be expressed in the root pericycle like AtSKOR, a strong expression of VvK5.1 ...
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Save 30% BSN - Syntha-6 Chocolate Milkshake with Free Shaker Bottle 5 Pounds You get a FREE BSN Shaker Bottle 25 Oz (Value $6.99) with each container of Syntha-6 5 LB purchased.
600ml Protein Shaker Bottle Capacity 800ml, but Measurement only shows up to 600ml With a flip top lid and a shaker ball Comes in two different measurements - Ml and Oz Great for holding your protein shakes in! Lightweight and portable bottles, with a lid (Only Yellow Lid available) so that it doesnt leak! Without an
Inspired by the simplicity, utility, and honesty of designs from the Shaker community, the Shaker Dinnerware collection is all thoughtful, functional form. No superflous line in sight, no unnecessary flourishes. The Serveware pieces are a sensible way to dish out dinner, with soft raised edges and slightly footed botto
Green spatter ceramic salt and pepper shakers with a stylistic man on the front of each shaker Rubber stopper in each one. All decoration is under glaze. Excellent condition. Measures 2.50 tall.
The Northeastern Woodworkers Associations September Meeting may be of interest to folks here... Thursday, September 11, 2008, 7:00 pm Shaker Heritage Society Meetinghouse Albany-Shaker Road, Albany, NY What Is Shaker Furniture? By Jerry Grant
This gene encodes a member of the potassium channel, voltage-gated, shaker-related subfamily. The encoded protein is one of the beta subunits, which are auxiliary proteins associating with functional Kv-alpha subunits. The encoded protein forms a heterodimer with the potassium voltage-gated channel, shaker-related subfamily, member 5 gene product and regulates the activity of the alpha subunit. [provided by RefSeq, May 2012 ...
Neurons could alter the properties and the amount ofI A by differentially regulating A-channel gene expression. Like their Drosophila homologs, thePanulirus shaker and shal genes both encode α-subunits for rapidly inactivating A-type channels, although with somewhat different properties than for the Drosophilachannels (Fig. 2, Table 1; M. Kim et al., 1995, 1996; Baro et al., 1996a). We compared the I As obtained from overexpressing shaker and shal cRNA inXenopus oocytes (lobsterI shaker and lobsterI shal) with the six pyloricI As (Fig. 2, Table 1). We discovered that the variations in pyloric I As were not consistent with the idea that distinct pyloric I As result from different mixtures of shaker and shal A-channels. Instead, we found that the pyloric cell I As qualitatively resemble lobster I shal more than lobster I shaker; however, no pyloricI A was identical in all parameters to lobsterI shal.. The voltage dependence of the six pyloric I As was quite variable but generally resembled ...
K(v)3.4 belongs to the shaw subfamily of shaker-type potassium channels. It conducts fast inactivating, high threshold currents in the central nervous system and in fast-twitch skeletal muscle fibers. The corresponding mouse gene, Kcnc4, consists of five exons spanning a region of 20 kb. Approximately 700 bp of regulatory sequence were delineated. It is GC rich and lacks typical TATA and CAAT motifs. Instead, seven Sp-1 and three E-box elements define putative regulatory sequences. The mouse K(v)3.4 mRNA has a size of 3639 bp, 1120 bp of which are 3 untranslated region. A transcript initiated from an alternative 5-exon was identified by RACE and verified by genomic analysis. This isoform, designated K(v)3.4d, is predominantly expressed in skeletal muscle and probably results from alternative promoter usage. It encodes a channel protein with a novel N-terminal cytoplasmic domain. It lacks the conserved sequence motifs encoding the shaw-type tetramerization domain and the ball peptide, which ...
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Shaker-type, voltage-gated K+ (KV1) channels are an important determinant of the resting membrane potential and diameter of small cerebral arteries. During hype...
All the data gathered on the effects of PIP2 on Kir6.2/SUR1 channels can be interpreted by a stabilization of the channel in the open conformation (Enkvetchakul et al., 2000). Similarly, our data can also be interpreted by a model based on the stabilization by PIP2 of the open conformation of KCNQ1/KCNE1 channels. This model is also comparable to Shaker channels kinetic models, i.e. one or more transitions of the four subunits followed by one or more additional concerted transitions (Schoppa and Sigworth, 1998). In the model that we used, one transition of the four subunits and one concerted transition were sufficient to convincingly fit the data. The model illustrates how variations in PIP2 levels are accompanied by changes in deactivation with no changes in activation kinetics. The requirement of the four domains to be in the on state to allow the channel to finally open makes this transition slow and rate limiting. Since this step is PIP2‐independent (kS4 is constant and k′S4 ...
In this study, we found that mutation E219R shifts Q-V relationship leftwards by 126 mV at 0 Ca2+ compared with WT and changes slope factor from 50 to 38 mV, indicating an increase of gating charge (Fig. 1A,B). In addition to the direct effects on voltage sensor movements, the mutation also shifts G-V relationship rightwards at 0 Ca2+ and increases Ca2+ sensitivity (Fig. 1C-F), which are the results of an electrostatic interaction between E219R and E321/E324 (Figs. 2 and 3) that alters the coupling among the activation gate, voltage sensor, and Ca2+ binding (Fig. 4; Table 2).. Ion channels often contain distinct structural domains for sensing physiological stimuli and the pore-activation gate. The coupling among these domains during channel activation is an important molecular process that has not been fully understood. One basic question is as follows: what kind of changes in the properties of channel function would indicate a change of coupling? It has been elegantly shown that, in ...
Lows in Motion is not your typical fundraiser; its a unique and energetic Shaker - pun intended. Our annual event provides an opportunity for community members to unite in the fight against Parkinsons disease (PD), with all funds raised going to Parkinson Society Saskatchewan (PSS). We pride ourselves on delivering an event chock full of entertainment and activities suitable for all ages.. PD is a chronic and progressive movement disorder, which means symptoms persist and worsen over time. It is classified as a neurodegenerative disease because of the characteristic degeneration of bodily tissues. Over 100,000 Canadians and nearly 1 million people in the United States are currently living with PD, with ten more receiving this life-altering diagnosis each day.. ...
Shaker tests are important for product validation - but what profile to run? Learn how to create accelerated shaker profiles for frequency domain testing.. In this presentation, well explore how concepts of vibration and durability analysis can be brought together to create a realistic shaker test. Well also show how quantifiable comparisons can be made between existing shaker profiles - for example, how to compare a sine sweep test to a random PSD test, or how to compare an existing test specification with new measured field vibration data. ...
The Amplicom PowerTel 725 Bundle includes the popular PowerTel 720 Amplified Cordless Telephone and the PowerTel 601 Wrist Shaker. The Amplicom PowerTel 720 cordless telephone offers high fidelity sound and low distortion when amplified. Expand your home telephone system with up to 4 additional handsets, and enjoy thes
Using the Shaker causes a steel ball to vibrate, creating a movement in your airways which travels deep into your lungs and shakes stubborn mucus loose.
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A vibration table is incorporated in the LDS V780 low-force shaker table from Brüel & Kjær, this helps to perform successful dynamics and vibration testing.
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... targets are Shaker-type (Kv1) K+ channels. HgTX1 shows high affinity with Kv1.1, Kv1.2, Kv1.3 voltage-gated potassium channels ... Hongotoxin belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 2 subfamily. There ... Hongotoxin (HgTX) is an ion channel toxin, which blocks Shaker-type (Kv1) K+ channels. The toxin is derived from the venom of ... HgTX4 and HgTX5 are potent selective inhibitors of Kv1 voltage-gated potassium channels (By similarity). ND, not determined. ...
Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has ... McCormack T, McCormack K (1995). "Shaker K+ channel beta subunits belong to an NAD(P)H-dependent oxidoreductase superfamily". ... Voltage-gated potassium channel subunit beta-1 is a protein that in humans is encoded by the KCNAB1 gene. Potassium channels ... "Entrez Gene: KCNAB1 potassium voltage-gated channel, shaker-related subfamily, beta member 1". England SK, Uebele VN, Shear H, ...
These include the sodium, potassium, calcium, ryanodine receptor, HCN, CNG, CatSper, and TRP channels. This large group of ion ... Shaker-related: Kv1.4 (KCNA4) Kvα3.x - Shaw-related: Kv3.3 (KCNC3), Kv3.4 (KCNC4) Kvα4.x - Shal-related: Kv4.1 (KCND1), Kv4.2 ( ... The transmembrane cation channel superfamily was defined in InterPro and Pfam as the family of tetrameric ion channels. ... Durell SR, Guy HR (2001). "A family of putative Kir potassium channels in prokaryotes". BMC Evolutionary Biology. 1: 14. doi: ...
The primary targets consist of voltage-gated Shaker-related potassium channels, ether-a-go-go related gene (HERG) potassium ... TmTx belongs to the short scorpion toxin superfamily and the potassium channel inhibitor family. Adhering to the nomenclature ... calcium-activated potassium channel), respectively. Another suggested target is the Kv1.6 channel, a voltage-gated potassium ... It belongs to the group of alpha potassium toxins (α-KTx: alpha toxin affecting potassium channels). This group contains short- ...
"Multiple potassium-channel components are produced by alternative splicing at the Shaker locus in Drosophila". Nature. 331 ( ... K+ channel subunits containing one pore domain can be assigned into one of two superfamilies: those that possess six ... channels; the KCNQ channels (originally known as KvLQT channels); the EAG-like K+ channels; and three types of calcium (Ca)- ... Potassium channels are the most diverse group of the ion channel family. They are important in shaping the action potential, ...
Such genetic methods allowed the genetic identification of the "Shaker" K+ channel gene in Drosophila before ion channel gene ... at ualberta.ca UMich Orientation of Proteins in Membranes families/superfamily-8 - Spatial positions of voltage gated potassium ... potassium channel blocker and potassium channel opener. Ion channel Potassium channel tetramerisation domain Ion channel family ... Voltage-gated potassium channels (VGKCs) are transmembrane channels specific for potassium and sensitive to voltage changes in ...
... shaker superfamily of potassium channels MeSH D12.776.543.550.425.750.900.500.124 - kv1.1 potassium channel MeSH D12.776. ... shaker superfamily of potassium channels MeSH D12.776.543.585.400.750.900.624.124 - kv1.1 potassium channel MeSH D12.776. ... shab potassium channels MeSH D12.776.543.550.425.750.900.249 - ether-a-go-go potassium channels MeSH D12.776.543.550.425.750. ... shab potassium channels MeSH D12.776.543.585.400.750.900.249 - ether-a-go-go potassium channels MeSH D12.776.543.585.400.750. ...
Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has ... McCormack T, McCormack K (1995). "Shaker K+ channel beta subunits belong to an NAD(P)H-dependent oxidoreductase superfamily". ... "Entrez Gene: KCNAB2 potassium voltage-gated channel, shaker-related subfamily, beta member 2". Hoek KS, Schlegel NC, Eichhoff ... Gu C, Jan YN, Jan LY (2003). "A conserved domain in axonal targeting of Kv1 (Shaker) voltage-gated potassium channels". Science ...
... shaker superfamily of potassium channels MeSH D12.776.157.530.400.600.900.500.124 - kv1.1 potassium channel MeSH D12.776. ... shab potassium channels MeSH D12.776.157.530.400.600.900.249 - ether-a-go-go potassium channels MeSH D12.776.157.530.400.600. ... kcnq potassium channels MeSH D12.776.157.530.400.600.900.124.249.500 - kcnq1 potassium channel MeSH D12.776.157.530.400.600. ... 900.124.249.750 - kcnq2 potassium channel MeSH D12.776.157.530.400.600.900.124.249.875 - kcnq3 potassium channel MeSH D12.776. ...
Potassium channels are the largest and most diverse class of voltage-gated channels, with over 100 encoding human genes. These ... Koishi R, Xu H, Ren D, Navarro B, Spiller BW, Shi Q, Clapham DE (March 2004). "A superfamily of voltage-gated sodium channels ... Webster SM, Del Camino D, Dekker JP, Yellen G (April 2004). "Intracellular gate opening in Shaker K+ channels defined by high- ... Voltage-gated ion-channels are usually ion-specific, and channels specific to sodium (Na+), potassium (K+), calcium (Ca2+), and ...
... of other important voltage conducting proteins such as the drosophilla-derived Shaker and the human hERG potassium channel. ... "Overview of molecular relationships in the voltage-gated ion channel superfamily". Pharmacological Reviews. 57 (4): 387-95. doi ... Calcium channel Potassium channel Sodium channel Schrempf H, Schmidt O, Kümmerlen R, Hinnah S, Müller D, Betzler M, Steinkamp T ... KcsA (K channel of streptomyces A) is a prokaryotic potassium channel from the soil bacteria Streptomyces lividans that has ...
The potassium channels that hanatoxin inhibits have huge diversity and are involved in a number of functions such as regulation ... Gonzalez, C. e.a. (2000). "Modulation of the Shaker K(+) channel gating kinetics by the S3-S4 linker". Journal of General ... http://supfam.org/SUPERFAMILY/cgi-bin/search.cgi?search_field=hanatoxin, consulted 10th Oct. 2012. http://www.t3db.org/toxins, ... Swartz, K.J.; MacKinnon, R. (1995). "An Inhibitor of the Kv2.1 Potassium Channel Isolated from the Venom of a Chilean Tarantula ...
... together forming the tetrameric channel's pore, the new channel had just two Shaker-like repeats, each of which was equipped ... dimerise to form a functional channel. "Two P domain potassium channels". Guide to Pharmacology. Retrieved 2019-05-28. Rang, HP ... a protein superfamily specialized for electrical signaling and ionic homeostasis". Science's STKE. 2004 (253): re15. doi: ... As implied by their name, TPC channels possess two pores and were named for their two Shaker-like repeats, which each have a ...
Four sequence-related potassium channel genes - shaker, shaw, shab, and shal - have been identified in Drosophila, and each has ... a new member of the neurexin superfamily, is localized at the juxtaparanodes of myelinated axons and associates with K+ ... "Entrez Gene: KCNA2 potassium voltage-gated channel, shaker-related subfamily, member 2". Coleman SK, Newcombe J, Pryke J, Dolly ... Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural ...
Some potassium channels: Inward-rectifier potassium channels: These channels allow potassium ions to flow into the cell in an " ... Cyclic nucleotide-gated channels: This superfamily of channels contains two families: the cyclic nucleotide-gated (CNG) ... together forming the tetrameric channel's pore, the new channel had just two Shaker-like repeats, each of which was equipped ... Potassium channels Voltage-gated potassium channels e.g., Kvs, Kirs etc. Calcium-activated potassium channels e.g., BKCa or ...
In a few cases, those of Kir1.1a, Kir6.1 and Kir6.2, for example, direct interaction with a member of the ABC superfamily has ... Inward-rectifier potassium channels (Kir, IRK) are a specific subset of potassium channels. To date, seven subfamilies have ... such as the delayed rectifier and A-type potassium channels. Those more "typical" potassium channels preferentially carry ... "Inwardly Recifying Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and ...
... results in activation of calcium-sensitive potassium channels, muscular contraction,[4] excitation of neurons, up-regulation of ... High-voltage-gated calcium channels include the neural N-type channel blocked by ω-conotoxin GVIA, the R-type channel (R stands ... to at least 1 site on the channel, as Ca2+-null CaM mutants abolish CGI in L-type channels. Not all channels exhibit the same ... P-type calcium channel ("Purkinje") /Q-type calcium channel. HVA (high voltage activated). Cav2.1 (CACNA1A). α2δ, β, possibly γ ...
In a few cases, those of Kir1.1a, Kir6.1 and Kir6.2, for example, direct interaction with a member of the ABC superfamily has ... Inward-rectifier potassium channels (Kir, IRK) are a specific subset of potassium channels. To date, seven subfamilies have ... such as the delayed rectifier and A-type potassium channels. Those more "typical" potassium channels preferentially carry ... "Inwardly Recifying Potassium Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and ...
Plant Shaker channels are members of the 6 transmembrane-1 pore (6TM-1P) cation channel superfamily as the animal Shaker (Kv) ... Shaker channels constitute the major pathway for K(+) in the plasma membrane. ... Shaker Superfamily of Potassium Channels / chemistry* * Shaker Superfamily of Potassium Channels / metabolism* ... cation channel superfamily as the animal Shaker (Kv) and HCN channels. All these channels are voltage-gated K(+) channels: Kv ...
INVOLVED IN potassium ion transmembrane transport (ortholog); FOUND IN axon; axon terminus; integral component of plasma ... ENCODES a protein that exhibits delayed rectifier potassium channel activity (ortholog); ... Superfamily-SCOP. BTB/POZ_fold. UniProtKB/Swiss-Prot. UniGene. Mm.62535. ENTREZGENE. ... potassium voltage gated channel, shaker related, subfamily, member 6; potassium voltage-gated channel subfamily A member 6; ...
Shaker complex. In a first stage, a large number of models of the complex are generated using high temperature molecular ... Potassium Channels * Scorpion Venoms * Shaker Superfamily of Potassium Channels * Water * agitoxin 2 ... Modeling the Structure of Agitoxin in Complex With the Shaker K+ Channel: A Computational Approach Based on Experimental ... In this final complex, the toxin is bound to the extracellular entrance of the channel along the pore axis via a combination of ...
... the chromoionophore compounds further comprise a second chromophoric moiety which is insensitive to potassium binding by the ... Potassium channel subunits of the Shaker-like superfamily share a characteristic six transmembrane/1 pore domain structure. ... The Shaker-like channel family includes the voltage-gated potassium channels as well as the delayed rectifier type channels ... A second superfamily of potassium channels is composed of the inward rectifying channels (Kir). Kir channels have the property ...
... targets are Shaker-type (Kv1) K+ channels. HgTX1 shows high affinity with Kv1.1, Kv1.2, Kv1.3 voltage-gated potassium channels ... Hongotoxin belongs to the short scorpion toxin superfamily. Potassium channel inhibitor family. Alpha-KTx 2 subfamily. There ... Hongotoxin (HgTX) is an ion channel toxin, which blocks Shaker-type (Kv1) K+ channels. The toxin is derived from the venom of ... HgTX4 and HgTX5 are potent selective inhibitors of Kv1 voltage-gated potassium channels (By similarity). ND, not determined. ...
Voltage-gated potassium channels (Kv) of the Shaker-related superfamily are assembled from membrane-integrated alpha subunits ... The beta subunits may increase Kv channel surface expression and/or confer A-type behavior to noninactivating Kv channels in ... Functional and molecular aspects of voltage-gated K+ channel beta subunits.. Pongs O1, Leicher T, Berger M, Roeper J, Bähring R ... Loss of function of Kv beta 1.1 subunits leads to a reduction of A-type Kv channel activity in hippocampal and striatal neurons ...
In mammalian axons, homomeric and heteromeric Kv1 channels of the Shaker superfamily mediate a range of fast activating, slowly ... 1996) Ultrastructural localization of Shaker-related potassium channel subunits and synapse-associated protein 90 to septate- ... but is densely packed with Shaker type Kv1 voltage-gated potassium channels (McNamara et al., 1993; Laube et al., 1996). The ... lacks both sodium channels and local exocytotic machinery, and yet contains a dense cluster of voltage-gated potassium channels ...
Potassium Channels/physiology. MESH. Shaker Superfamily of Potassium Channels. MESH. Thermodynamics. MESH. ... Structure of the inactivating gate from the Shaker voltage gated K⁺ channel analyzed by NMR spectroscopy ... which blocks the open channel from the cytoplasmic side. Inactivating ball domains of various Kv channels are also biologically ... which blocks the open channel from the cytoplasmic side. Inactivating ball domains of various Kv channels are also biologically ...
Members of the superfamily of voltage-gated ion channels are the molecular components underlying electrical excitability in ... Luminescence Resonance Energy Transfer Studies of the Shaker Potassium Voltage-Gated Ion Channel. Welcome to the IDEALS ... Luminescence Resonance Energy Transfer Studies of the Shaker Potassium Voltage-Gated Ion Channel. Posson, David John ... Luminescence Resonance Energy Transfer Studies of the Shaker Potassium Voltage-Gated Ion Channel. ...
Kv4 channels may underlie the IA in DRG neurons. We combined electrophysiology, molecular biology (whole-tissue and single-cell ... Matching Kv4 channel properties, activation and inactivation of this IA occur in the subthreshold range of membrane potentials ... Contrasting the expression patterns of Kv4 channels in the central and peripheral nervous systems, we discuss possible ... Recent studies have demonstrated DRG hyperexcitability associated with downregulation of A-type K+ channels; however, the ...
For one member of this superfamily, the transiently voltage-activated Shaker H4 potassium channel, specific amino acid residues ... The main classes of voltage-dependent channels (sodium-, calcium-, and potassium-selective channels) have closely related ... Furthermore, variation at one of these amino acid positions among naturally occurring potassium channels may account for most ... Voltage-dependent ion channels are responsible for electrical signaling in neurons and other cells. ...
These include the sodium, potassium, calcium, ryanodine receptor, HCN, CNG, CatSper, and TRP channels. This large group of ion ... Shaker-related: Kv1.4 (KCNA4) Kvα3.x - Shaw-related: Kv3.3 (KCNC3), Kv3.4 (KCNC4) Kvα4.x - Shal-related: Kv4.1 (KCND1), Kv4.2 ( ... The transmembrane cation channel superfamily was defined in InterPro and Pfam as the family of tetrameric ion channels. ... Durell SR, Guy HR (2001). "A family of putative Kir potassium channels in prokaryotes". BMC Evolutionary Biology. 1: 14. doi: ...
Shaker Superfamily of Potassium Channels/*chemistry/*metabolism Identifiers. URN: urn:nbn:se:su:diva-18687ISI: 000246599900015 ... Contribution of hydrophobic and electrostatic interactions to the membrane integration of the Shaker K+ channel voltage sensor ...
... that AKT1 and KAT1 are members of a family of plant channels similar in structure and sequence to the shaker superfamily of ... Among the several shaker-like channel genes identified in plants isAKT2 (Cao et al., 1995; Ketchum and Slayman, 1996), a K+ ... 2000) A shaker-like channel with weak rectification is expressed in both source and sink phloem tissues of Arabidopsis. Plant ... 1998b) Identification and disruption of a plant shaker-like outward channel involved in K+ release into the xylem sap. Cell 94: ...
Shaker Superfamily of Potassium Channels Medicine & Life Sciences * Palinuridae Medicine & Life Sciences ... Expression of Panulirus shaker potassium channel splice variants. Receptors and Channels. 1998 Jul 31;5(5):291-304. ... title = "Expression of Panulirus shaker potassium channel splice variants",. abstract = "In Drosophila shaker voltage-dependent ... Expression of Panulirus shaker potassium channel splice variants. In: Receptors and Channels. 1998 ; Vol. 5, No. 5. pp. 291-304 ...
... including the Shaker potassium channel (Kreusch et al., 1998) and, as an isolated domain, the Kv1.2 channel itself (Minor et al ... This superfamily includes members whose SCOP family is the "tetramerization domain of potassium channels." This structure, ... The assertions of the presence of the SCOP superfamilies "POZ domain" and "voltage-gated potassium channels" are the only two ... Crystal structure of the tetramerization domain of the Shaker potassium channel. Nature. 392:945-948. ...
Potassium Channels * Fluorescence In Situ Hybridization * Shaker Superfamily of Potassium Channels * Chromosomes, Human, Pair 3 ... Localization of two potassium channel β subunit genes, KCNA1B and KCNA2B. Schultz, D., Litt, M., Smith, L., Thayer, M. & ... Skeletal muscle and small-conductance calcium-activated potassium channels. Pribnow, D., Johnson-Pais, T., Bond, C. T., Keen, J ...
Expression of background potassium channels in rat DRG is cell-specific and down-regulated in a neuropathic pain model. Pollema ... Properties and functional role of voltage-dependent potassium channels in dendrites of rat cerebellar Purkinje neurons. Martina ... Voltage-dependent potassium currents during fast spikes of rat cerebellar Purkinje neurons: Inhibition by BDS-I toxin. Martina ... Acid-sensing ion channels contribute to chemosensitivity of breathing-related neurons of the nucleus of the solitary tract. ...
Shaker Superfamily of Potassium Channels Chromosomes, Human, Pair 3 Chromosomes, Human, Pair 1 ... N2 - The gating properties and current amplitudes of mammalian voltage- activated Shaker potassium channels are modulated by at ... AB - The gating properties and current amplitudes of mammalian voltage- activated Shaker potassium channels are modulated by at ... The gating properties and current amplitudes of mammalian voltage- activated Shaker potassium channels are modulated by at ...
Potassium Channels * Spectrum Analysis * Shaker Superfamily of Potassium Channels * Lanthanoid Series Elements ... Atomic scale movement of the voltage-sensing region in a potassium channel measured via spectroscopy. Cha, A., Snyder, G. E., ...
Highly temperature-sensitive behavior of voltage-gated potassium channels provides a mechanistic model for how heat-activated ... TRP channels serve as temperature and pain sensors. ... Shaker ILT and Shaker V2 channels. For Shaker WT channel I2 was ... channels. As members of the tetrameric cation channel superfamily, TRP channels and Kv channels are structurally similar. They ... Activation of Shaker potassium channels. II. Kinetics of the V2 mutant channel * NE Schoppa ...
Shaker Superfamily of Potassium Channels Chemical Compounds * NADP Chemical Compounds * Aldo-Keto Reductases Chemical Compounds ... "Kvβ subunit oxidoreductase activity and Kv1 potassium channel trafficking",. abstract = "Voltage-gated Kv1 potassium channels ... Voltage-gated Kv1 potassium channels consist of poreforming α subunits and cytoplasmic Kvβ subunits. The latter play diverse ... Kvβ subunit oxidoreductase activity and Kv1 potassium channel trafficking. Journal of Biological Chemistry. 2002 Mar 8;277(10): ...
Recently, synthetic mutagenesis studies in the Drosophila melanogaster Shaker channel and analysis of human disease-causing ... highly selective pore typical of potassium channels. This channel has evolved to yield qualitatively different ion permeability ... The N.at-K v 3.2 potassium channel has an unusual weak inward rectifier phenotype. Several mutations of two amino acids in the ... The typical selectivity filter in potassium channels is formed by a tetrameric arrangement of the carbonyl groups of the ...
We further focus on the mechanisms of FFA modulation operating on voltage-gated and ligand-gated ion channel function, ... We further focus on the mechanisms of FFA modulation operating on voltage-gated and ligand-gated ion channel function, ... has been interpreted as a protective mechanism possibly operative on ion channels, which in some cases is of stimulatory nature ... has been interpreted as a protective mechanism possibly operative on ion channels, which in some cases is of stimulatory nature ...
Clinical-pathologic correlations in voltage-gated Kv1 potassium channel complex-subtyped autoimmune painful polyneuropathy. ... P/Q- and N-type calcium-channel antibodies: Oncological, neurological, and serological accompaniments. Zalewski, N. L., Lennon ...
Shaker Superfamily of Potassium Channels Shaker Superfamily of Potassium Channels Flagellin フラゲリン ...
Shaker Superfamily of Potassium Channels. *kappa-conotoxin PVIIA. Grant support. *GM 58187/GM/NIGMS NIH HHS/United States ... Electrostatic recognition and induced fit in the kappa-PVIIA toxin binding to Shaker potassium channel.. Huang X1, Dong F, Zhou ... and electrostatic calculations were performed to study the binding process of kappa-PVIIA to the Shaker potassium channel and ... BD simulations, guided by electrostatic interactions, led to an initial alignment between the toxin and the channel protein. MD ...
Shaker Superfamily of Potassium Channels 25% * DNA Probes 17% 199 Scopus citations ... A family of putative potassium channel genes in Drosophila. Butler, A., Wei, A., Baker, K. & Salkoff, L., 1989, In: Science. ... A human calcium-activated potassium channel gene expressed in vascular smooth muscle. McCobb, D. P., Fowler, N. L., ... Jegla, T. & Salkoff, L., May 30 1995, In: Receptors and Channels. 3, 1, p. 51-60 10 p.. Research output: Contribution to ...
D12.776.157.530.400.600.900.124.500 Shab Potassium Channels .. D12.776.157.530.400.600.900.500 Shaker Superfamily of Potassium ... KCNB2 Potassium Channel .. Kv2 Potassium Channels .. Kv2.1 Potassium Channel .. Kv2.2 Potassium Channel .. Potassium Channel, ... Potassium Channel, Kv2.2 .. Potassium Channels, Kv2 .. Potassium Channels, Shab .. A subfamily of shaker potassium channels ... Shab Potassium Channels .. CDRK Potassium Channel .. DRK1 Potassium Channel .. ...
  • The movement of four S4s, one from each identical subunit of Shaker, is coupled to the "gate" which opens and closes the pore. (illinois.edu)
  • Here, by a combination of structural modeling and biochemical and cell biological analyses of structure-based mutations, we investigate the potential role for putative Kvβ subunit enzymatic activity in the trafficking of Kv1 channels. (elsevier.com)
  • Loss-of-function mutations in the Caenorhabditis elegans gene sup-18 suppress the defects in muscle contraction conferred by a gain-of-function mutation in SUP-10, a presumptive regulatory subunit of the SUP-9 two-pore domain K + channel associated with muscle membranes. (prolekare.cz)
  • Four of these subfamilies, Kv1 (Shaker), Kv2 (Shab), Kv3 (Shaw) and Kv4 (Shal), consist of pore-forming alpha subunits that associate with different types of beta subunit. (ebi.ac.uk)
  • Primary structure of a beta subunit of alpha-dendrotoxin-sensitive K+ channels from bovine brain. (pnas.org)
  • Additionally, the background K+ channel subunit TASK-1, which comprises four transmembrane segments and two pore domains, is also involved in both oxygen- and acid-sensing in peripheral chemoreceptors. (antibody-antibodies.com)
  • However, the proportions of the different syndromes, the numbers with associated tumours and the relationships with potassium channel subunit antibody specificities have been unclear. (ox.ac.uk)
  • 1989) of what is now known to be the CNG channel α subunit facilitated its molecular characterization. (ubc.ca)
  • Expression in mammalian cells helped resolve confusion regarding the JVL of the rod CNG channel a subunit. (ubc.ca)
  • PCR was used to construct cDNA clones which code for both the 63 and 80 kDa forms of the a subunit of the rod CNG channel. (ubc.ca)
  • The cloned CNG channel β subunit cDNA codes for a protein with a predicted molecular mass of 155 kDa (Korschen et al, 1995). (ubc.ca)
  • The expressed a subunit reconstituted alone did not generate functional cGMP-gated channels. (ubc.ca)
  • The system presented here will be useful to further define CNG α and β subunit interactions and to carry out structure-function studies on the channel using a biochemical efflux assay. (ubc.ca)
  • Moreover, FS stress-induced tyrosine phosphorylation of both the NR2B subunit of the NMDA subtype of glutamate receptor and the K + -channel subunit Kvβ2 was regulated by SIRPα. (jneurosci.org)
  • BK Ca channels are formed by subunit homotetramers, each comprising a conserved transmembrane voltage-sensing domain (VSD), a pore domain, and a large intracellular ligand-binding domain (Fig. 1), recently visualized by cryoelectron microscopy (Wang and Sigworth, 2009). (sciencedocbox.com)
  • Different Shaker family α-subunit genes generate distinct voltage-dependent K + currents when expressed in heterologous expression systems. (jneurosci.org)
  • [3] [4] For most voltage-gated ion channels , the pore-forming subunit(s) are called the α subunit, while the auxiliary subunits are denoted β, γ, and so on. (orange.com)
  • The HVCN1 and Putative tyrosine-protein phosphatase proteins do not contain an expected ion conduction pore domain, but rather have homology only to the voltage sensor domain of voltage gated ion channels. (wikipedia.org)
  • This problem of resolving proteins in the "twilight zone" is particularly acute in the study of ion channels. (rupress.org)
  • which provides easily parsable files containing the sequences, and SCOP (structural classification of proteins) superfamily assignments, of domains from the PDB. (rupress.org)
  • Sensing the heat given off by an object or the temperature of the environment is possible, at least in part, because of proteins called temperature-sensitive TRP ion channels. (elifesciences.org)
  • Voltage-gated ion channels are membrane proteins containing a selective pore that allows permeable ions to transit the membrane in response to a change in the transmembrane voltage. (biomedcentral.com)
  • These are all highly similar proteins, with only small amino acid changes causing the diversity of the voltage-dependent gating mechanism, channel conductance and toxin binding properties. (ebi.ac.uk)
  • Antibodies to Kv1 potassium channel-complex proteins leucine-rich, glioma inactivated 1 protein and contactin-associated protein-2 in limbic encephalitis, Morvan's syndrome and acquired neuromyotonia. (ox.ac.uk)
  • The remaining 18 sera were negative for potassium channel subunits and associated proteins by the methods employed. (ox.ac.uk)
  • The interaction between these channels and Caspr2 was suggested to depend on PDZ scaffolding proteins. (pubmedcentralcanada.ca)
  • To directly evaluate the role of PDZ domain proteins in the function of Caspr2, we examined the ability of transgenic Caspr2 molecules lacking either their cytoplasmic domain (Caspr2dCT), or their PDZ-binding sequence (Caspr2dPDZ), to restore Kv1 channel clustering in Caspr2 null mice. (pubmedcentralcanada.ca)
  • These domains contain a unique set of protein complexes including, ion channels, cell adhesion molecules (CAMs) and cytoskeletal adapter proteins. (pubmedcentralcanada.ca)
  • Genetic and phenotypic studies of yeast have identified several proteins involved in the regulation of potassium transport. (asm.org)
  • Sodium, calcium, and potassium channels form a family of integral membrane proteins that selectively regulate ion conductance across an otherwise impermeable lipid membrane. (pnas.org)
  • In addition, the coexpression of Kir2.1 ion channels with synapse-associated 97 proteins was partially impaired. (intechopen.com)
  • The primary structure of ChTX is similar to a number of neurotoxins of diverse origin, which suggests that ChTX is a member of a superfamily of proteins that modify ion-channel activities. (smartox-biotech.com)
  • Aldo-keto reductases ( AKRs ) form a superfamily of proteins characterised by their common three-dimensional structure and reaction mechanism in catalysing the reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H)-dependent oxido-reduction of carbonyl groups. (biomedcentral.com)
  • I N T R O D U C T I O N Large-conductance voltage- and Ca 2+ -activated K + (BK Ca or MaxiK) channels are ubiquitous membrane proteins that potently regulate cellular excitability (Toro et al. (sciencedocbox.com)
  • Ion channels are pore-forming proteins that help to establish and control the small voltage gradient across the plasma membrane of all living cells (see cell potential ) by allowing the flow of ions down their electrochemical gradient . (wikidoc.org)
  • In terms of function, these proteins transport potassium (K + ) , with a greater tendency for K + uptake than K + export. (wikipedia.org)
  • Our analysis found that several ion channels and a class of thioesterases constitute the possible cyclic nucleotide binding proteins in plants. (biomedcentral.com)
  • This protein superfamily of more than 140 members is one of the largest groups of signal transduction proteins, and many family members are the molecular targets for toxins and therapeutic agents. (aspetjournals.org)
  • The functional elements of the ion channel superfamily of proteins can be divided into three complementary aspects: ion conductance, pore gating, and regulation. (aspetjournals.org)
  • Ion channels are pore-forming membrane proteins that allow ions to pass through the channel pore. (orange.com)
  • [1] Ion channels are one of the two classes of ionophoric proteins, the other being ion transporters . (orange.com)
  • Ion channels are integral membrane proteins , typically formed as assemblies of several individual proteins. (orange.com)
  • Despite the absence of crystal structures of plant Shaker channels, functional analyses coupled to homology modeling, mostly based on Kv and HCN crystals, have permitted the identification of several regions contributing to plant Shaker channel gating. (nih.gov)
  • Functional and molecular aspects of voltage-gated K+ channel beta subunits. (nih.gov)
  • This nonconventional axo-axonic contact extends beyond the perisomatic chemical GABAergic synaptic boutons to the distal AIS, lacks both sodium channels and local exocytotic machinery, and yet contains a dense cluster of voltage-gated potassium channels whose functional contribution is unknown. (jneurosci.org)
  • Contrasting the expression patterns of Kv4 channels in the central and peripheral nervous systems, we discuss possible functional roles of these channels in primary sensory neurons. (frontiersin.org)
  • In vitro phenotypic modulation of VSMCs was associated to an increased functional expression of Kv1.3 channels, and only selective Kv1.3 channel blockers were able to inhibit porcine VSMC proliferation. (bvsalud.org)
  • These subunits do not themselves possess any functional activity, but appear to form heteromeric channels with Kv2 subunits, and thus modulate Shab channel activity [ PMID: 9305895 ]. (ebi.ac.uk)
  • The functional channel is a homotetramer. (creativebiomart.net)
  • Potassium channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. (antibody-antibodies.com)
  • Voltage-gated potassium (Kv) channels represent the most complex class of voltage-gated ion channels from both functional and structural standpoints. (antibody-antibodies.com)
  • I then spent 8 years working on ion channels as drug targets in industry, before returning to academics to explore the functional roles of newly discovered K+ channels in neuronal signaling. (psu.edu)
  • We study the functional evolution of the major neuronal ion channel gene families in order to better understand how they pattern the activity of neurons and circuits. (psu.edu)
  • Functional evolution of Erg potassium channel gating reveals an ancient origin for IKr. (psu.edu)
  • Expanded functional diversity of Shaker K + channels in cnidarians is driven by gene expansion. (psu.edu)
  • In eukaryotic voltage-gated sodium and calcium channels the functional unit is formed by assembly of four homologous domains of a single polypeptide chain. (pnas.org)
  • In contrast, in both eukaryotic and prokaryotic potassium channels the functional unit is a homo-tetramer formed from identical monomers that each correspond to one of the sodium or calcium channel domains ( 1 ). (pnas.org)
  • Reconstitution of the heterologously expressed channel complex comprising the 80 kDa α and complete β subunits generated functional channels. (ubc.ca)
  • Our investigation revealed a reduced level of Kir2.1 channels in deaf patients indicating a crucial role for the functional Shaker superfamily of K+ channels in the non-diseased hearing system. (intechopen.com)
  • 1]. Reconstitution of functional voltage-gated chloride channels from complementary fragments of CLC-1. (bionity.com)
  • By comparing our binding data to functional measurements of potency in full-length channels containing the same single substitutions, we found that two residues, L633 and I636, reduced potency more severely than affinity when mutated, and proposed that these residues are involved in a post-binding transition event. (ubc.ca)
  • This likely reflects a decrease in its ability to form a gating ring in the intact channel and explains the reported inhibition of opening by thismutation.The work presented in this thesis demonstrates the value of studying the C-terminus of the HCN channel in isolation to uncover the mechanism by which the HCN C-terminus and cAMP binding control channel opening that would otherwise be hidden by functional experiments. (ubc.ca)
  • Finol-Urdaneta, R.K., Strüver, N. and Terlau, H.: Molecular and functional differences between heart mKv1.7 channel isoforms. (uni-kiel.de)
  • Rapid inactivation of voltage-gated K+ (Kv) channels is mediated by an N-terminal domain (inactivating ball domain) which blocks the open channel from the cytoplasmic side. (uni-regensburg.de)
  • Synthetic inactivating ball domains from different Kv channels with hardly any sequence homology mediate quite similar effects even on unrelated Kv channel subtypes whose inactivation domain has been deleted. (uni-regensburg.de)
  • Whole-cell recordings demonstrate a robust tetraethylammonium-resistant (20 mM) and 4-aminopyridine-sensitive (5 mM) I A . Matching Kv4 channel properties, activation and inactivation of this I A occur in the subthreshold range of membrane potentials and the rate of recovery from inactivation is rapid and voltage-dependent. (frontiersin.org)
  • The N-terminus of the channel is associated with beta subunits that can modify the inactivation properties of the channel as well as affect expression levels. (creativebiomart.net)
  • Oxidation of the bound NADPH strongly decreases N-type inactivation of potassium channel activity (By similarity). (uniprot.org)
  • δ-conotoxin inhibits fast inactivation of voltage-dependent sodium channels . (rug.nl)
  • The cysteine arrangements are the same for omega, delta and kappa families, even though omega conotoxins are calcium channel blockers, whereas delta conotoxins delay the inactivation of sodium channels, and kappa conotoxins are potassium channel blockers. (rug.nl)
  • In Drosophila shaker voltage-dependent potassium channels, alternative splicing at the amino and carboxy termini produces currents with different electrophysiological characteristics. (elsevier.com)
  • A voltage-dependent potassium channel gene designated Shaw was initially isolated from Drosophila melanogaster (Fruit fly). (ebi.ac.uk)
  • The Shal potassium channel was found in Drosophila melanogaster (Fruit fly). (ebi.ac.uk)
  • BcsTx3 showed a high affinity for Drosophila Shaker IR channels over rKv1.2, hKv1.3 and rKv1.6, and was not active on Na V channels. (tcdb.org)
  • This gene encodes a voltage-gated delayed potassium channel that is phylogenetically related to the Drosophila Shaker channel. (creativebiomart.net)
  • Our data demonstrate that under phototoxic conditions, Drosophila photoreceptors upregulate stress response pathways and simultaneously, downregulate expression of phototransduction components, ion transporters, and calcium channels. (biomedcentral.com)
  • Voltage-gated potassium (K V ) channels, first identified as the gene encoding the Shaker mutation in the fruit fly Drosophila , exemplify the second structural architecture in the ion channel superfamily. (aspetjournals.org)
  • In mammalian axons, homomeric and heteromeric Kv1 channels of the Shaker superfamily mediate a range of fast activating, slowly inactivating (delayed rectifier) repolarizing currents. (jneurosci.org)
  • The gating properties and current amplitudes of mammalian voltage- activated Shaker potassium channels are modulated by at least two associated β subunits (Kvβ1.1 and Kvβ1.2). (elsevier.com)
  • Together, these data suggest that NADP + binding and/or the integrity of the binding pocket structure, but not catalytic activity, of Kvβ subunits is required for intracellular trafficking of Kv1 channel complexes in mammalian cells and for axonal targeting in neurons. (elsevier.com)
  • Antibodies that immunoprecipitate (125)I-alpha-dendrotoxin-labelled voltage-gated potassium channels extracted from mammalian brain tissue have been identified in patients with neuromyotonia, Morvan's syndrome, limbic encephalitis and a few cases of adult-onset epilepsy. (ox.ac.uk)
  • Understanding plant K + channel gating poses several challenges, despite many similarities to that of mammalian Kv and Shaker channel models. (plantphysiol.org)
  • Turkish scorpion Buthacus macrocentrus: General characterization of the venom and description of Bu1, a potent mammalian Na+-channel a-toxin Toxicon, 59, 408-415. (unam.mx)
  • In the yeast Saccharomyces cerevisiae the high-affinity potassium uptake system is encoded by the partially redundant genes TRK1 and TRK2 ( 12 , 24 ). (asm.org)
  • It is difficult to evaluate the extent to which differential Shaker family gene expression contributes to endogenous K + current diversity, because the specific Shaker family gene or genes responsible for a given K + current are still unknown for nearly all adult neurons. (jneurosci.org)
  • Rapidly inactivating voltage-gated potassium channels (KCNA4), of the *shaker-related subfamily. (oxfordreference.com)
  • Nearly all of the members of this superfamily, found in bacteria, archaea and eukaryotes, catalyze cation uptake and/or efflux driven by ATP hydrolysis. (tcdb.org)
  • For one member of this superfamily, the transiently voltage-activated Shaker H4 potassium channel, specific amino acid residues have now been identified that affect channel blockade by the small ion tetraethylammonium, as well as the conduction of ions through the pore. (sciencemag.org)
  • In this channel, mutation of residues R2 or R3 in one of the four S4 helices allows an influx of cations through the aqueous gating-pore along the length of S4. (biomedcentral.com)
  • The validity of the predicted structure for the complex was assessed by calculating the effects of mutating charged and polar residues of both the toxin and the channel protein, with the calculated effects correlating reasonably well with experimental data. (nih.gov)
  • The fourth TM domain has positively charged residues at every third residue and acts as a voltage sensor, which triggers the conformational change that opens the channel pore in response to a displacement in membrane potential [ PMID: 10712896 ]. (ebi.ac.uk)
  • Our data show that mutations of both charges to neutral residues (K538Q and D411N) accelerate the time dependence of charge movement while both mutant channels are gated with faster kinetics than control over a physiologically relevant range of depolarizations. (ubc.ca)
  • External pH modulates EAG superfamily K+ channels through EAG-specific acidic residues in the voltage sensor. (psu.edu)
  • By creating a number of shortened constructs we have shown experimentally that the CTD does indeed contain a stretch of ∼20 α-helical residues preceded by a nonhelical region adjacent to the final transmembrane segment and that the efficiency of assembly of channels in the membrane progressively decreases as the CTD residues are removed. (pnas.org)
  • We have used site-directed mutagenesis to explore residues that are thought to form two electrostatic countercharge centers on either side of a conserved phenylalanine (Phe) residue within the S2 and S3 α-helices of the voltage sensor domain ( VSD ) of Kv channels. (plantphysiol.org)
  • Consistent with molecular dynamic simulations of KAT1, we show that the voltage dependence of the channel gate is highly sensitive to manipulations affecting these residues. (plantphysiol.org)
  • We interpret these findings in the context of the effects on hydration of amino acid residues within the VSD and with an inherent bias of the VSD , when hydrated around a central Phe residue, to the closed state of the channel. (plantphysiol.org)
  • The charybdotoxin receptor of a Shaker K+ channel: peptide and channel residues mediating molecular recognition. (smartox-biotech.com)
  • Point mutagenesis of all 30 solvent-exposed residues identified the part of the CTX molecular surface making contact with the receptor in the K+ channel. (smartox-biotech.com)
  • A mutagenic scan of the S5-S6 linker sequence of the Shaker K+ channel identified those channel residues influencing CTX binding affinity. (smartox-biotech.com)
  • The Shaker residues making the strongest contribution to toxin binding are located close to the pore-lining sequence, and more distant residues on both sides of this region influence CTX binding weakly, probably by an electrostatic mechanism. (smartox-biotech.com)
  • The strategic arrangement of ion channels into subcellular compartments is a fundamental organizing principle linking neuronal form and function. (jneurosci.org)
  • Voltage-gated channels allow the selective flow of ions across the hydrophobic lipid bilayer of a cell, opening and closing in response to changes in the voltage across the membrane. (illinois.edu)
  • In contrast to another 32 superfamilies adopting this motif, AKRs do not require metal ions for functionality, and bind NAD(P)H cofactor in an extended anti-conformation so that they can catalyse 4-pro-R hydride transfer and thus belong to the large group of A-face oxidoreductases. (biomedcentral.com)
  • Ion channels regulate the flow of ions across the membrane in all cells. (wikidoc.org)
  • While some channels permit the passage of ions based solely on charge, the archetypal channel pore is just one or two atoms wide at its narrowest point. (wikidoc.org)
  • It conducts a specific species of ion, such as sodium or potassium , and conveys them through the membrane single file--nearly as quickly as the ions move through free fluid. (wikidoc.org)
  • In addition, ion channels figure in a wide variety of biological processes that involve rapid changes in cells, such as cardiac , skeletal , and smooth muscle contraction , epithelial transport of nutrients and ions, T-cell activation and pancreatic beta-cell insulin release. (wikidoc.org)
  • Ion channels may be classified by the nature of their gating, the species of ions passing through those gates, and the number of gates (pores). (wikidoc.org)
  • At membrane potentials negative to potassium's reversal potential , inwardly rectifying K + channels support the flow of positively charged K + ions into the cell, pushing the membrane potential back to the resting potential. (wikipedia.org)
  • The phenomenon of inward rectification of K ir channels is the result of high-affinity block by endogenous polyamines , namely spermine , as well as magnesium ions, that plug the channel pore at positive potentials, resulting in a decrease in outward currents. (wikipedia.org)
  • The rate of ion transport through the channel is very high (often 10 6 ions per second or greater). (orange.com)
  • Ions pass through channels down their electrochemical gradient , which is a function of ion concentration and membrane potential, "downhill", without the input (or help) of metabolic energy (e.g. (orange.com)
  • Ions often move through the segments of the channel pore in single file nearly as quickly as the ions move through free solution. (orange.com)
  • Here we report that the homologous voltage-gated potassium (Kv) channels also exhibit high temperature sensitivity comparable to that of TRPV1, which is detectable under specific conditions when the voltage sensor is functionally decoupled from the activation gate through either intrinsic mechanisms or mutations. (elifesciences.org)
  • The α subunits have six transmembrane segments, homologous to a single domain of the sodium channels. (wikidoc.org)
  • [4] IRK channels possess a pore domain, homologous to that of voltage-gated ion channels , and flanking transmembrane segments (TMSs). (wikipedia.org)
  • Members of the superfamily of voltage-gated ion channels are the molecular components underlying electrical excitability in nerves and muscle. (illinois.edu)
  • The main classes of voltage-dependent channels (sodium-, calcium-, and potassium-selective channels) have closely related molecular structures. (sciencemag.org)
  • Brownian dynamics (BD) and molecular dynamics (MD) simulations and electrostatic calculations were performed to study the binding process of kappa-PVIIA to the Shaker potassium channel and the structure of the resulting complex. (nih.gov)
  • GENTAUR antibody-antibodies.com The Marketplace for Antibodies : Molecular physiology of oxygen-sensitive potassium channels. (antibody-antibodies.com)
  • Molecular physiology of oxygen-sensitive potassium channels. (antibody-antibodies.com)
  • Molecular biology strategies have recently allowed the identification of the K+ channel subunits expressed in these specialized cells. (antibody-antibodies.com)
  • These results demonstrate that while the molecular assembly of the JXP requires the cytoplasmic domain of Caspr2, its carboxy-terminal PDZ-binding motif is dispensable for Kv1 channel clustering. (pubmedcentralcanada.ca)
  • A heterologous expression system was developed to examine molecular aspects of the α and β subunits of the CNG channel. (ubc.ca)
  • Structure, Molecular Modeling and Function of the First Potassium Channel Blocker, Urotoxin, Isolated from the Venom of the Australian Scorpion Urodacus Yaschenkoi Molecular Pharmacology, 86, 28-41. (unam.mx)
  • Molecular cloning and biochemical characterization of the first Na+-channel alpha-type toxin peptide (Acra4) from Androctonus crassicauda scorpion venom Biochimie, 95, 1216-1222. (unam.mx)
  • Here we review the molecular and evolutionary relationships among the families within the voltage-gated-like (VGL 1 ) ion channel superfamily. (aspetjournals.org)
  • and three types of calcium (Ca)-activated K + channels (BK, IK and SK) [ PMID: 11178249 ]. (ebi.ac.uk)
  • 1998). ω-Phonetoxin-IIA: a calcium channel blocker from the spider Phoneutria nigriventer. (tcdb.org)
  • I move on to do postdoctoral work on the diversity and function of large-conductance calcium-activated (BK) channels in Dr. Richard Aldrich's lab at Stanford. (psu.edu)
  • ω-conotoxin inhibits N-type voltage-dependent calcium channels . (rug.nl)
  • [13] Because N-type voltage-dependent calcium channels are related to algesia (sensitivity to pain ) in the nervous system, ω-conotoxin has an analgesic effect: the effect of ω-conotoxin M VII A is 100 to 1000 times that of morphine . (rug.nl)
  • Purification, sequence, and model structure of charybdotoxin, a potent selective inhibitor of calcium-activated potassium channels. (smartox-biotech.com)
  • Voltage-gated calcium (Ca V ) channels have a similar structure ( Fig. 1 ). (aspetjournals.org)
  • Several other families of ion channels also have this architecture, including calcium-activated potassium (K Ca ) channels, cyclic nucleotide-gated (CNG) and hyperpolarization-activated cyclic nucleotide-modulated (HCN) channels, and transient receptor potential (TRP) channels ( Fig. 1 and see below). (aspetjournals.org)
  • A reverse genetic strategy was used to isolate Arabidopsis plants containing "knockout" mutations in AKT1 and AKT2 , two members of a K + channel gene family. (plantphysiol.org)
  • This channel has evolved to yield qualitatively different ion permeability when compared to all other members of this gene family. (biomedcentral.com)
  • The gene sup-9 of the nematode Caenorhabditis elegans encodes a two-pore domain K + channel [28] . (prolekare.cz)
  • The loss-of-function mutations in the human ether-à-go-go-related gene (hERG) K+ channel serve as one of the primary genetic substrates for congenital long QT syndrome (LQTS), and unlike most Kv channels with fast-activating kinetics, hERG channels have unusually slow activation kinetics. (ubc.ca)
  • 2]. Mutations in the human skeletal muscle chloride channel gene (CLCN1) associated with dominant and recessive myotonia congenita. (bionity.com)
  • Thus it generally is believed that diverse neuronal K + current phenotypes arise, in part, from differences in Shaker family gene expression among neurons. (jneurosci.org)
  • In this paper we explore the role of differential Shaker family gene expression in creating transient K + current ( I A ) diversity in the 14-neuron pyloric network of the spiny lobster, Panulirus interruptus . (jneurosci.org)
  • The cyclic nucleotide-gated (CNG) cation channel of rod photoreceptors plays an important role in the perception of light. (ubc.ca)
  • The direct binding of cyclic AMP upon adrenaline release also enhances channel opening, leading to an increased frequency of action potential. (ubc.ca)
  • In addition to basic understanding, the significance of learning about HCN channel modulation by cAMP is that there may be therapeutic advantage of controlling heart rate via drug interaction with the cyclic nucleotide binding pocket. (ubc.ca)
  • Hyperpolarization-activated Cyclic Nucleotide-gated, HCN, channels contribute to the membrane potential of excitable cells including pacemaker cells of the heart and neurons in the brain. (ubc.ca)
  • Since two-pore domain K + channels regulate the resting membrane potentials of numerous cell types, we suggest that the SUP-18 IYD regulates the activity of the SUP-9 channel using NADH as a coenzyme and thus couples the metabolic state of muscle cells to muscle membrane excitability. (prolekare.cz)
  • Four transmembrane/two-pore domain K + channels play a key role in establishing the resting membrane potentials of many cell types and in modulating their responses to neurotransmitters and second messengers [14] - [16] . (prolekare.cz)
  • K + channel subunits containing one pore domain can be assigned into one of two superfamilies: those that possess six transmembrane (TM) domains and those that possess only two TM domains. (ebi.ac.uk)
  • Several voltage-gated K+ channel subunits comprising six transmembrane segments and a single pore domain (Kv1.2, Kv1.5, Kv2.1, Kv3.1, Kv3.3, Kv4.2 and Kv9.3) are reversibly blocked by hypoxia when expressed in heterologous expression systems. (antibody-antibodies.com)
  • Inward rectifiers also differ from tandem pore domain potassium channels , which are largely responsible for "leak" K + currents. (wikipedia.org)
  • These studies indicate that ChTX is useful as a probe of Ca2+-activated K+-channel function and suggest that the proposed tertiary structure of ChTX may provide insight into the mechanism of channel block. (smartox-biotech.com)
  • HgTX1 shows high affinity with Kv1.1, Kv1.2, Kv1.3 voltage-gated potassium channels, but much lower affinity with Kv1.6 (see table 1 and 2). (wikipedia.org)
  • Episodic ataxia type 1 (EA-1) is an autosomal dominant neurological disorder caused by mutations in the potassium channel Kv1.1. (curehunter.com)
  • Evidence is presented that the decrease in 5-HT2CR editing is caused by down-regulation of adenosine deaminase ADAR2 and that editing of at least one other ADAR2 target, potassium channel Kv1.1, is decreased after SCI. (curehunter.com)
  • A commonly used bioinformatics technique is to assert, based on sequence similarity, that a domain within a channel of interest has the same structure as a reference domain for which the structure is known. (rupress.org)
  • In this study, we exploit recent advances in structural genomics to calculate the sequence-based probability of the presence of putative domains in a number of ion channels. (rupress.org)
  • In particular, for the COOH terminus of the BK channel we find a number of literature proposed domains for which the assertion of common structure based on common sequence has a nontrivial probability of error. (rupress.org)
  • We also explore cases in the channel literature where there appears to be little sequence-based evidence for domains that have been proposed based on sequence similarity. (rupress.org)
  • For each sequence in the query set, we used the hmmsearch program of the HMMer package ( http://hmmer.wustl.edu/ , version 2.3.2 with the default parameters under Cygwin and OS X) to run the query sequence over each of the 9,939 profiles in the Superfamily database ( Fig. 1 ). (rupress.org)
  • We refer to the sequence that was used to seed each Superfamily profile as the "seed sequence. (rupress.org)
  • The typical selectivity filter in potassium channels is formed by a tetrameric arrangement of the carbonyl groups of the conserved amino-acid sequence Gly-Tyr-Gly. (biomedcentral.com)
  • N.at-K v 3.2 , a naturally occurring potassium channel of the Kv3 sequence family, mediates ion permeation through a modified gating pore, not the canonical, highly selective pore typical of potassium channels. (biomedcentral.com)
  • Biochemical characterization revealed that BcsTx3 is a 50 amino acid peptide crosslinked by four disulfide bridges, and sequence comparison allowed BcsTx3 to be classified as a novel type of sea anemone toxin acting on K V channels. (tcdb.org)
  • Sequence analyses predict its CTD will consist of an unordered region followed by an α-helix, which has a propensity to form a multimeric coiled-coil motif, and which could form an association domain in the homotetrameric NaChBac channel. (pnas.org)
  • Based on sequence homology the chloride channels can be subdivided into a number of groups. (bionity.com)
  • Although functionally diverse, AKRs form a protein superfamily based on their high sequence identity and common protein fold, the (α/(β) 8 -barrel structure. (biomedcentral.com)
  • There are many superfamilies of Znf motifs, varying in both sequence and structure. (embl-heidelberg.de)
  • All of these physiological processes are mediated in part by members of the voltage-gated ion channel protein superfamily ( Fig. 1 ) ( Yu and Catterall, 2004 ). (aspetjournals.org)
  • The inwardly rectifying potassium channels comprise the simplest structural motif in the ion channel protein superfamily. (aspetjournals.org)
  • 2018). Efficient Enzymatic Ligation of Inhibitor Cystine Knot Spider Venom Peptides: Using Sortase A To Form Double-Knottins That Probe Voltage-Gated Sodium Channel Na1.7. (tcdb.org)
  • However, it appears that many of these peptides modulate the activity of ion channels . (rug.nl)
  • Biochemical and physiological characterization of a new Na-channel specific peptide from the venom of the Argentinean scorpion Tityus trivittatus Peptides, 68, 11-16. (unam.mx)
  • A K+ channel blocking peptide from the Cuban scorpion Rhopalurus garridoi Peptides, 53, 42-47. (unam.mx)
  • In this final complex, the toxin is bound to the extracellular entrance of the channel along the pore axis via a combination of hydrophobic, hydrogen bonding, and electrostatic interactions. (nih.gov)
  • Specific site-directed mutagenesis experiments are suggested to verify and confirm the structure of the toxin-channel complex. (nih.gov)
  • Hongotoxin (HgTX) is an ion channel toxin, which blocks Shaker-type (Kv1) K+ channels. (wikipedia.org)
  • Hongotoxin belongs to the short scorpion toxin superfamily. (wikipedia.org)
  • The second measures distances between S4 sites and a scorpion toxin bound to the symmetric axis of the channel just above the pore. (illinois.edu)
  • Electrostatic recognition and induced fit in the kappa-PVIIA toxin binding to Shaker potassium channel. (nih.gov)
  • BD simulations, guided by electrostatic interactions, led to an initial alignment between the toxin and the channel protein. (nih.gov)
  • The final complex structure was stabilized through electrostatic interactions with the positively charged side chain of Lys7 of kappa-PVIIA deeply inserted into the channel pore and other hydrogen bonds and by hydrophobic interactions involving Phe9 and Phe23 of the toxin. (nih.gov)
  • 2013). BcsTx3 is a founder of a novel sea anemone toxin family of potassium channel blocker. (tcdb.org)
  • The toxin reversibly blocks channel activity by interacting at the external pore of the channel protein with an apparent Kd of 2.1 nM. (smartox-biotech.com)
  • Our results argue that block of voltage-gated K+ channels results from the binding of one toxin molecule, so that Lys27 enters the pore and interacts with K+ (or Na+) in the ion conduction pathway. (smartox-biotech.com)
  • KCNA1 has several biochemical functions, for example, delayed rectifier potassium channel activity, potassium channel activity, potassium ion transmembrane transporter activity. (creativebiomart.net)
  • The transmembrane cation channel superfamily was defined in InterPro and Pfam as the family of tetrameric ion channels. (wikipedia.org)
  • ACCN4 belongs to the superfamily of acid-sensing ion channels, which are proton-gated, amiloride-sensitive sodium channels. (antibody-antibodies.com)
  • Although potassium channels have been well characterized, much less is known about the structural features of voltage-gated sodium channels (Na V s). (pnas.org)
  • 13 ) isolated NaChBac, a simple prokaryotic sodium channel from Bacillus halodurans that, like potassium channels, but unlike eukaryotic sodium channels, is composed of a single 6TM domain. (pnas.org)
  • μ-conotoxin inhibits voltage-dependent sodium channels in muscles. (rug.nl)
  • [17] Mu-conotoxins target the muscle-specific voltage-gated sodium channels, [7] and are useful probes for investigating voltage-dependent sodium channels of excitable tissues. (rug.nl)
  • The α subunits have an overall structural resemblance to those of the sodium channels and are equally large. (wikidoc.org)
  • Neuronal action potentials are generated and modulated by a precise combination of ionic currents produced by the activity of ion channels. (elifesciences.org)
  • These channels are the primary subunits contributing to transient, voltage-dependent potassium currents in the nervous system (A currents) and the heart (transient outward current), and are inhibited by free fatty acids [ PMID: 15269337 ]. (ebi.ac.uk)
  • To define the antibody specificities, we looked for binding of serum antibodies and their effects on potassium channel currents using human embryonic kidney cells expressing the potassium channel subunits. (ox.ac.uk)
  • Comparing these currents with the I A s obtained from oocytes injected with Panulirus shaker and shal cRNA (lobster I shaker and lobster I shal , respectively) reveals that the pyloric cell I A s more closely resemble lobster I shal than lobster I shaker . (jneurosci.org)
  • Those more "typical" potassium channels preferentially carry outward (rather than inward) potassium currents at depolarized membrane potentials, and may be thought of as "outwardly rectifying. (wikipedia.org)
  • When first discovered, inward rectification was named "anomalous rectification" to distinguish it from outward potassium currents. (wikipedia.org)
  • Other inwardly rectifying channels, termed "strong inward rectifiers," carry very little outward current at all, and are mainly active at voltages negative to the K + reversal potential, where they carry inward current (the much larger currents below the 0 nA line in figure 1). (wikipedia.org)
  • In the ADAM11 mutant, GABAergic release was not altered, but the ultrarapid electrical signal was absent, demonstrating that the dense presynaptic cluster of Kv1 ion channels at these terminals mediate electrical transmission. (jneurosci.org)
  • For example, KAT1 is primarily expressed in guard cells so it is logical to propose that it encodes the well-studied inward-rectifying K + channels that mediate stomatal opening. (plantphysiol.org)
  • Because "voltage-gated" channels underlie the nerve impulse and because "transmitter-gated" channels mediate conduction across the synapses , channels are especially prominent components of the nervous system . (wikidoc.org)
  • HgTX2, HgTX3, HgTX4 and HgTX5 are potent selective inhibitors of Kv1 voltage-gated potassium channels (By similarity). (wikipedia.org)
  • Selective absence of these channels at the pinceau due to mutation of ADAM11 spares spontaneous GABA release from basket cells at the perisomatic synapse yet eliminates ultrarapid ephaptic inhibitory synchronization of Purkinje cell firing. (jneurosci.org)
  • When the channel is in a depolarized conformation, the omega pore closes and the canonical ion-selective pore opens. (biomedcentral.com)
  • The modulation of voltage-gated K+ (Kv) channels, involved in cell proliferation, arises as a potential therapeutic approach for the prevention of intimal hyperplasia present in in-stent restenosis (ISR) and allograft vasculopathy (AV). We studied the effect of PAP-1, a selective blocker of Kv1.3 channels, on development of intimal hyperplasia in vitro and in vivo in 2 porcine models of vascular injury. (bvsalud.org)
  • These are usually highly regulated K + selective leak channels. (ebi.ac.uk)
  • Purified ChTX is a potent and selective inhibitor of the approximately 220-pS Ca2+-activated K+ channel present in GH3 anterior pituitary cells and primary bovine aortic smooth muscle cells. (smartox-biotech.com)
  • Thus, Pi efflux could be mediated by uniporters or ion selective channels. (plantcell.org)
  • The archetypal channel pore is just one or two atoms wide at its narrowest point and is selective for specific species of ion, such as sodium or potassium . (orange.com)
  • Receptors and Channels , 5 (5), 291-304. (elsevier.com)
  • In eukaryotic cells, K + channels are involved in neural signalling and generation of the cardiac rhythm, act as effectors in signal transduction pathways involving G protein-coupled receptors (GPCRs) and may have a role in target cell lysis by cytotoxic T-lymphocytes [ PMID: 1373731 ]. (ebi.ac.uk)
  • Selamectin works by replacing glutamate which normally interacts with receptors that open chloride channels at muscle synapses found in parasites. (bionity.com)
  • They may have agonistic or antagonistic effects on the receptors, block ion channel pores or disrupt the interaction with neighboring molecules. (scielo.br)
  • There are commonly additional regulatory domains which serve to regulate ion conduction and channel gating. (wikipedia.org)
  • the shape of this surface implies that the outer opening of the Shaker channel conduction pore abruptly widens to a 25 x 35 A plateau. (smartox-biotech.com)
  • Examples include the N-terminal T1 domain of Shaker channels ( 5 ) and C-terminal domains (CTDs) of the ether-a-go-go (EAG) ( 6 ) and the inwardly rectifying (K IR ) channels ( 7 ). (pnas.org)
  • Whole-cell current recordings of K ir 2 inwardly-rectifying potassium channels expressed in an HEK293 cell . (wikipedia.org)
  • A channel that is "inwardly-rectifying" is one that passes current (positive charge) more easily in the inward direction (into the cell) than in the outward direction (out of the cell). (wikipedia.org)
  • Temperature-sensitive transient receptor potential (TRP) ion channels are members of the large tetrameric cation channels superfamily but are considered to be uniquely sensitive to heat, which has been presumed to be due to the existence of an unidentified temperature-sensing domain. (elifesciences.org)
  • The crystal structures of a number of potassium channels have been determined ( 2 - 4 ), which have confirmed the tetrameric nature of the channels and details of their transmembrane (TM) regions. (pnas.org)
  • Chloride channel subunits contain between 1 and 12 transmembrane segments. (bionity.com)
  • Nonetheless, it is widely assumed in the literature that eukaryotic and prokaryotic channels share common folds. (rupress.org)
  • The first measures distances between the four identical S4 amino-acid sites on the homotetrameric K+ channel. (illinois.edu)
  • Furthermore, variation at one of these amino acid positions among naturally occurring potassium channels may account for most of their differences in sensitivity to tetraethylammonium. (sciencemag.org)
  • Two of the different amino terminal splice forms were expressed with two alternatively spliced pore forms to produce channels with markedly different characteristics. (elsevier.com)
  • One of the amino termini produced a channel with transient characteristics while the other produced a delayed rectifier-type channel. (elsevier.com)
  • and by changing some of the amino acids in the voltage-gated channel Yang and Zheng could decouple these normally linked actions. (elifesciences.org)
  • Further experiments showed that replacing some of the amino acids in the voltage-gated potassium ion channel with different amino acids could cause the channel to be either opened or closed by heat. (elifesciences.org)
  • Subsequently, several vetebrate potassium channels with similar amino acid sequences were found and, together with the D. melanogaster channel, now constitute the Kv3 family. (ebi.ac.uk)
  • TRK1 encodes the most active transporter, corresponding to a large protein, 1,235 amino acids long, containing eight membrane-spanning domains and with a four-MPM (membrane-pore-membrane) structure similar to that of shaker K + channels ( 9 , 12 ). (asm.org)
  • Charybdotoxin (ChTx) is a 37 amino acid peptide isolated from the venom of the scorpion Leiurus quinquestriatus hebraeus that blocks voltage-gated and large conductance Ca 2+ activated K + channels K Ca 1.1 in nanomolar concentrations (IC 50 ~ 3 nM). (smartox-biotech.com)
  • Accelerates KCNA4 channel closure (By similarity). (uniprot.org)
  • Accelerates the closure of heteromeric channels formed by KCNA1 and KCNA4 (By similarity). (uniprot.org)
  • The beta subunits may increase Kv channel surface expression and/or confer A-type behavior to noninactivating Kv channels in heterologous expression systems. (nih.gov)
  • Harris-Warrick, Ronald M. / Expression of Panulirus shaker potassium channel splice variants . (elsevier.com)
  • Reduced cardiac sodium channel expression is a known causal mechanism in AF. (bvsalud.org)
  • qPCR and western blotting were used to assess ion channel expression. (bvsalud.org)
  • The reduction in INa occurred in association with reduced expression of SCN5a and voltage gated Na+ (NaV1.5) channels as well as a shift in INa activation kinetics. (bvsalud.org)
  • In the KcsA potassium channel the CTD has been shown to be critical for expression, tetramerization, and stability of the closed channel ( 8 , 9 ) as well as having a role in pH sensing ( 10 , 11 ). (pnas.org)
  • Expression of connexins and Kir2.1 ion channels was investigated in the blood cells of deaf patients prior to cochlear implantation, and the results show significantly decreased amounts of connexin26 and connexin43. (intechopen.com)
  • 2009), which modulate the channel activation mechanism and, because of their subtype-restricted expression pattern, confer tissue-specific effects to BK Ca channel function (Orio et al. (sciencedocbox.com)
  • Venom components of the scorpion Centruroides limpidus modulate cytokine expression by T helper lymphocytes: Identification of ion channel-related toxins by mass spectrometry International Immunopharmacology, 84, 106505. (unam.mx)
  • SIGNIFICANCE STATEMENT This study identifies ADAM11 as the first essential molecule for the proper localization of potassium ion channels at presynaptic nerve terminals, where they modulate excitability and the release of neural transmitters. (jneurosci.org)
  • The precise localization of ion channels to specialized sites along dendrites and axons is crucial for nervous system function. (pubmedcentralcanada.ca)
  • In terms of primary structure, they are unrelated to known cation channels or other types of anion channels. (bionity.com)
  • Voltage-gated Kv1 potassium channels consist of poreforming α subunits and cytoplasmic Kvβ subunits. (elsevier.com)
  • Contribution of hydrophobic and electrostatic interactions to the membrane integration of the Shaker K+ channel voltage sensor domain. (diva-portal.org)
  • This is because parts of the ion channel-which act like a 'voltage sensor' and only shift when the membrane voltage changes-normally keep the channel closed and directly open the channel when they move. (elifesciences.org)
  • Both approaches revealed that, after a change in membrane voltage caused the voltage sensor to move, the ion channel remained closed until a high temperature caused it to open. (elifesciences.org)
  • Analyses of the CTDs of 32 putative prokaryotic Na V sequences suggest that a CTD helical bundle is a structural feature conserved throughout the bacterial sodium channel family. (pnas.org)
  • This also includes the 2-TM inward-rectifier potassium channels (Pfam PF01007) found primarily in eukaryotes. (wikipedia.org)
  • This combination of computational methods permits the identification of two possible structural models of AgTx2 in complex with the Shaker K+ channel, additional structural analysis providing further evidence in favor of a single model. (nih.gov)
  • Despite the structural homology to other Kv channels, how individual S4 charges in hERG are positioned and moved under the influence of membrane voltage changes remains controversial. (ubc.ca)
  • We are also interested how the structural polarity of neurons evolved as it relates to directional signaling and ion channel distribution. (psu.edu)
  • The architectures of the ion channel families consist of four variations built upon a common pore-forming structural theme. (aspetjournals.org)
  • We have cloned alternatively spliced forms of shaker from the spiny lobster Panulirus interruptus. (elsevier.com)
  • Accelerates the closure of heteromeric channels formed by KCNA2, KCNA5 and KCNA6 (By similarity). (uniprot.org)
  • Conotoxin κM-RIIIJ, a tool targeting asymmetric heteromeric K v 1 channels. (uni-kiel.de)
  • Promotes the closure of KCNA1, KCNA2 and KCNA5 channels (By similarity). (uniprot.org)
  • Potassium channel inhibitor family. (wikipedia.org)
  • Imperial J., Bansal P.S., Alewood P.F., Daly N.L., Craik D.J., Sporning A., Terlau H., Lopez - Vera E., Bandyopadhyay P.K. and Olivera B.M.: A Novel Conotoxin Inhibitor of Kv1.6 Channel and nAChR Subtypes Defines a New Superfamily of Conotoxins. (uni-kiel.de)