Mediates the voltage-dependent potassium ion permeability of excitable membranes. Channels open or close in response to the voltage difference across the membrane, letting potassium ions pass in accordance with their electrochemical gradient.
Catalysis of the transmembrane transfer of a potassium ion by a delayed rectifying voltage-gated channel. A delayed rectifying current-voltage relation is one where channel activation kinetics are time-dependent, and activation is slow.
Am. J. Physiol. 274, G901-11-G901-11 (1998)[PubMed:9612272]
Kv2.2, homologous to the shab family of Drosophila voltage-gated K+ channels, was isolated from human and canine colonic circular smooth muscle-derived mRNA. Northern hybridization analysis performed on RNA prepared from tissues and RT-PCR performed on RNA isolated from dispersed and selected smooth muscle cells demonstrate that Kv2.2 is expressed in smooth muscle cells found in all regions of the canine gastrointestinal (GI) tract and in several vascular tissues. Injection of Kv2.2 mRNA into Xenopus oocytes resulted in the expression of a slowly activating K+ current (time to half maximum current, 97 +/- 8.6 ms) mediated by 15 pS (symmetrical K+) single channels. The current was inhibited by tetraethylammonium (IC50 = 2.6 mM), 4-aminopyridine (IC50 = 1.5 mM at +20 mV), and quinine (IC50 = 13.7 microM) and was insensitive to charybdotoxin. Low concentrations of quinine (1 microM) were used to preferentially block the slow component of the delayed rectifier current in native colonic myocytes. These data suggest that Kv2.2 may contribute to this current in native GI smooth muscle cells.
Am. J. Physiol. 274, G901-11-G901-11 (1998)[PubMed:9612272]
Kv2.2, homologous to the shab family of Drosophila voltage-gated K+ channels, was isolated from human and canine colonic circular smooth muscle-derived mRNA. Northern hybridization analysis performed on RNA prepared from tissues and RT-PCR performed on RNA isolated from dispersed and selected smooth muscle cells demonstrate that Kv2.2 is expressed in smooth muscle cells found in all regions of the canine gastrointestinal (GI) tract and in several vascular tissues. Injection of Kv2.2 mRNA into Xenopus oocytes resulted in the expression of a slowly activating K+ current (time to half maximum current, 97 +/- 8.6 ms) mediated by 15 pS (symmetrical K+) single channels. The current was inhibited by tetraethylammonium (IC50 = 2.6 mM), 4-aminopyridine (IC50 = 1.5 mM at +20 mV), and quinine (IC50 = 13.7 microM) and was insensitive to charybdotoxin. Low concentrations of quinine (1 microM) were used to preferentially block the slow component of the delayed rectifier current in native colonic myocytes. These data suggest that Kv2.2 may contribute to this current in native GI smooth muscle cells.
The process of creating protein oligomers, compounds composed of a small number, usually between three and ten, of identical component monomers. Oligomers may be formed by the polymerization of a number of monomers or the depolymerization of a large protein polymer.
Am. J. Physiol. 274, G901-11-G901-11 (1998)[PubMed:9612272]
Kv2.2, homologous to the shab family of Drosophila voltage-gated K+ channels, was isolated from human and canine colonic circular smooth muscle-derived mRNA. Northern hybridization analysis performed on RNA prepared from tissues and RT-PCR performed on RNA isolated from dispersed and selected smooth muscle cells demonstrate that Kv2.2 is expressed in smooth muscle cells found in all regions of the canine gastrointestinal (GI) tract and in several vascular tissues. Injection of Kv2.2 mRNA into Xenopus oocytes resulted in the expression of a slowly activating K+ current (time to half maximum current, 97 +/- 8.6 ms) mediated by 15 pS (symmetrical K+) single channels. The current was inhibited by tetraethylammonium (IC50 = 2.6 mM), 4-aminopyridine (IC50 = 1.5 mM at +20 mV), and quinine (IC50 = 13.7 microM) and was insensitive to charybdotoxin. Low concentrations of quinine (1 microM) were used to preferentially block the slow component of the delayed rectifier current in native colonic myocytes. These data suggest that Kv2.2 may contribute to this current in native GI smooth muscle cells.
Protein involved in the transport of ions. Such proteins are usually transmembrane and mediate a movement of ions across cell membranes. Transport may be passive (facilitated diffusion; down the electrochemical gradient), or active (against the electrochemical gradient). Active transport requires energy which may come from light, oxidation reactions, ATP hydrolysis, or cotransport of other ions or molecules.
Protein involved in the transport of a molecule (metabolite, protein, etc), a ion or an electron across cell membranes, inside the cell or in a tissue fluid.
Protein which is part of a transmembrane protein complex that forms a hydrophilic channel across the lipid bilayer through which specific inorganic ions can diffuse down their electrochemical gradients. The channels are usually gated and only open in response to a specific stimulus, such as a change in membrane potential (voltage-gated) or the binding of a ligand (ligand-gated channel).
Protein which is part of a transmembrane protein complex that forms a hydrophilic channel across the lipid bilayer through which potassium ions can diffuse down their electrochemical gradient. The channels are gated and only open in response to a specific stimulus, such as a change in membrane potential (voltage-gated). They are important for the regulation of the resting membrane potential and for the control of the shape and frequency of action potentials.
Protein which is a component of a voltage-gated channel. Voltage-gated ion channels are responsible for the electrical activity in a variety of cell types. They probably exist in all life forms.
A reference proteome is a set of protein sequences derived from a complete proteome which constitutes a defined standard for a particular user community. Reference proteomes are manually defined according to a number of criteria. They cover the proteomes of well- studied model organisms and other proteomes of interest for biomedical and biotechnological research. Reference proteomes have been selected to provide broad coverage of the tree of life, and constitute a representative cross-section of the taxonomic diversity to be found within UniProtKB.
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