Mediates the voltage-dependent potassium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a potassium-selective channel through which potassium ions may pass in accordance with their electrochemical gradient.
CuratedUniProtKB
According to TCDB this is a transporter from family:
voltage-gated ion channel (VIC) superfamily 1.A.1.2.10
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.
Proc. Natl. Acad. Sci. U.S.A. 88, 7892-7895 (1991)[PubMed:1715584]
We have cloned a cDNA (designated RAK) coding for a delayed-rectifier K current (IRAK) from adult rat heart atrium and expressed it in Xenopus oocytes. RAK differs from the cloned rat brain K current, BK2 [McKinnon, D. (1989) J. Biol. Chem. 264, 8230-8236], by one amino acid at residue 411. RAK expressed in oocytes compares closely to the intrinsic adult rat atrial delayed-rectifier current measured by using whole-cell recording of single isolated cells. Northern blot analysis confirmed the presence of the channel in adult rat atrium, and to a lesser extent, in rat ventricle. IRAK activates with time constants ranging from 58 ms at -20 mV to 6 ms at +60 mV and does not show significant inactivation over 800 ms. It is blocked by 4-aminopyridine greater than barium much greater than tetraethylammonium chloride, which is similar to the relative potencies of these blockers on the native delayed rectifier current. We conclude that the main delayed rectifier K current in adult rat atria is virtually identical to a neuronal delayed rectifier, BK2.
Catalysis of the transmembrane transfer of a potassium ion by an outwardly-rectifying voltage-gated channel. An outwardly rectifying current-voltage relation is one where at any given driving force the outward flow of K+ ions exceeds the inward flow for the opposite driving force.
Catalysis of facilitated diffusion of a potassium ion (by an energy-independent process) involving passage through a transmembrane aqueous pore or channel without evidence for a carrier-mediated mechanism.
J. Biol. Chem. 264, 8230-8236 (1989)[PubMed:2722779]
A putative second potassium channel expressed in rat brain is identified by cloning and characterization of cDNA clones. Two cDNA clones, isolated from rat brain libraries, encode a 499-residue protein that is 80% identical with a previously described rat brain potassium channel and 68% identical with a Drosophila potassium channel. This new potassium channel is called BK2 to distinguish it from the previously described potassium channel (BK1). The BK2 gene, unlike the Drosophila potassium channel gene complex, appears to produce a single, large (approximately 9.5-kilobase) RNA transcript. Southern analysis of rat genomic DNA indicates that the BK1 and BK2 transcripts are the products of independent genes. Analysis of the distribution of BK2 transcripts in rat brain by in situ hybridization histochemistry suggests that the BK2 gene is ubiquitously expressed by central nervous system neurons. Identification of this putative second mammalian potassium channel cDNA indicates the existence of a potassium channel gene family, confirming electrophysiological data on the diversity of potassium channels expressed in rat brain.
Catalysis of the transmembrane transfer of a potassium ion by a voltage-gated channel. A voltage-gated channel is a channel whose open state is dependent on the voltage across the membrane in which it is embedded.
Proc. Natl. Acad. Sci. U.S.A. 87, 9411-9415 (1990)[PubMed:2251283]
We recently isolated a family of three closely related mouse K+ channel genes (MK1, MK2, and MK3) with coding regions contained in single uninterrupted exons. Here we have used patch-clamp recordings from Xenopus oocytes injected with mRNA to show that MK3 encodes a channel with biophysical and pharmacological properties indistinguishable from those of voltage-gated type n K+ channels in T cells. In addition, we used the polymerase chain reaction to demonstrate the presence of MK3 mRNA in T cells. These data suggest that MK3 may encode the T-cell voltage-gated type n K+ channel. We also show that MK3 and MK2 are localized on human chromosomes 13 and 12, respectively.
The process that contributes to the act of creating the structural organization of the optic nerve. This process pertains to the physical shaping of a rudimentary structure. The sensory optic nerve originates from the bipolar cells of the retina and conducts visual information to the brainstem. The optic nerve exits the back of the eye in the orbit, enters the optic canal, and enters the central nervous system at the optic chiasm (crossing) where the nerve fibers become the optic tract just prior to entering the hindbrain.
Proc. Natl. Acad. Sci. U.S.A. 87, 9411-9415 (1990)[PubMed:2251283]
We recently isolated a family of three closely related mouse K+ channel genes (MK1, MK2, and MK3) with coding regions contained in single uninterrupted exons. Here we have used patch-clamp recordings from Xenopus oocytes injected with mRNA to show that MK3 encodes a channel with biophysical and pharmacological properties indistinguishable from those of voltage-gated type n K+ channels in T cells. In addition, we used the polymerase chain reaction to demonstrate the presence of MK3 mRNA in T cells. These data suggest that MK3 may encode the T-cell voltage-gated type n K+ channel. We also show that MK3 and MK2 are localized on human chromosomes 13 and 12, respectively.
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.
IEAInterPro 2 GO
Pathways
According to Reactome, this protein belongs to the following pathway:
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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