The Kir2.1 inward-rectifier potassium channel is a lipid-gated ion channel encoded by the KCNJ2 gene. [5] [6] [7] [8]
The Kir2.1 inward-rectifier potassium channel is a lipid-gated ion channel encoded by the KCNJ2 gene. [5] [6] [7] [8]
A defect in this gene is associated with Andersen-Tawil syndrome. [9]
A mutation in the KCNJ2 gene has also been shown to cause short QT syndrome. [10]
In neurogenetics, Kir2.1 is used in Drosophila research to inhibit neurons, as overexpression of this channel will hyperpolarize cells.
In optogenetics, a trafficking sequence from Kir2.1 has been added to halorhodopsin to improve its membrane localization. The resulting protein eNpHR3.0 is used in optogenetic research to inhibit neurons with light. [11]
Expression of Kir2.1 gene in human HEK293 cells induce a transient outward current, creating a steady membrane potential close to the reversal potential of potassium. [12]
Kir2.1 has been shown to interact with:
Andersen–Tawil syndrome, also called Andersen syndrome and long QT syndrome 7, is a rare genetic disorder affecting several parts of the body. The three predominant features of Andersen–Tawil syndrome include disturbances of the electrical function of the heart characterised by an abnormality seen on an electrocardiogram and a tendency to abnormal heart rhythms, physical characteristics including low-set ears and a small lower jaw, and intermittent periods of muscle weakness known as hypokalaemic periodic paralysis.
The renal outer medullary potassium channel (ROMK) is an ATP-dependent potassium channel (Kir1.1) that transports potassium out of cells. It plays an important role in potassium recycling in the thick ascending limb (TAL) and potassium secretion in the cortical collecting duct (CCD) of the nephron. In humans, ROMK is encoded by the KCNJ1 gene. Multiple transcript variants encoding different isoforms have been found for this gene.
Inward-rectifier potassium channels (Kir, IRK) are a specific lipid-gated subset of potassium channels. To date, seven subfamilies have been identified in various mammalian cell types, plants, and bacteria. They are activated by phosphatidylinositol 4,5-bisphosphate (PIP2). The malfunction of the channels has been implicated in several diseases. IRK channels possess a pore domain, homologous to that of voltage-gated ion channels, and flanking transmembrane segments (TMSs). They may exist in the membrane as homo- or heterooligomers and each monomer possesses between 2 and 4 TMSs. In terms of function, these proteins transport potassium (K+), with a greater tendency for K+ uptake than K+ export. The process of inward-rectification was discovered by Denis Noble in cardiac muscle cells in 1960s and by Richard Adrian and Alan Hodgkin in 1970 in skeletal muscle cells.
Kir6.2 is a major subunit of the ATP-sensitive K+ channel, a lipid-gated inward-rectifier potassium ion channel. The gene encoding the channel is called KCNJ11 and mutations in this gene are associated with congenital hyperinsulinism.
PSD-95 also known as SAP-90 is a protein that in humans is encoded by the DLG4 gene.
G protein-activated inward rectifier potassium channel 2 is a protein that in humans is encoded by the KCNJ6 gene. Mutation in KCNJ6 gene has been proposed to be the cause of Keppen-Lubinsky Syndrome (KPLBS).
Potassium inwardly-rectifying channel, subfamily J, member 4, also known as KCNJ4 or Kir2.3, is a human gene.
Potassium inwardly-rectifying channel, subfamily J, member 8, also known as KCNJ8, is a human gene encoding the Kir6.1 protein. A mutation in KCNJ8 has been associated with cardiac arrest in the early repolarization syndrome.
G protein-activated inward rectifier potassium channel 4(GIRK-4) is a protein that in humans is encoded by the KCNJ5 gene and is a type of G protein-gated ion channel.
ATP-sensitive inward rectifier potassium channel 12 is a lipid-gated ion channel that in humans is encoded by the KCNJ12 gene.
G protein-activated inward rectifier potassium channel 1(GIRK-1) is encoded in the human by the gene KCNJ3.
ATP-sensitive inward rectifier potassium channel 10 is a protein that in humans is encoded by the KCNJ10 gene.
Potassium inwardly-rectifying channel, subfamily J, member 15, also known as KCNJ15 is a human gene, which encodes the Kir4.2 protein.
Lin-7 homolog A is a protein that in humans is encoded by the LIN7A gene.
Lin-7 homolog B is a protein that in humans is encoded by the LIN7B gene.
Potassium inwardly-rectifying channel, subfamily J, member 16 (KCNJ16) is a human gene encoding the Kir5.1 protein.
Potassium inwardly-rectifying channel, subfamily J, member 14 (KCNJ14), also known as Kir2.4, is a human gene.
G protein-activated inward rectifier potassium channel 3 is a protein that in humans is encoded by the KCNJ9 gene.
Potassium inwardly-rectifying channel, subfamily J, member 13 (KCNJ13) is a human gene encoding the Kir7.1 protein.
The Kir2.6 also known as inward rectifier potassium channel 18 is a protein that in humans is encoded by the KCNJ18 gene. Kir2.6 is an inward-rectifier potassium ion channel.
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