Channelpedia

Kir3.2

Description: potassium inwardly-rectifying channel, subfamily J, member 6
Gene: Kcnj6     Synonyms: Kir3.2, BIR1, GIRK2, KATP2, KCNJ7, Kcnj6

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Introduction


Experimental data


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Gene

RGD ID Chromosome Position Species
2959 11 35025118-35116500 Rat
731945 16 94970290-95219303 Mouse
1313992 21 38996785-39288696 Human

Kcnj6 : potassium inwardly-rectifying channel, subfamily J, member 6


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Transcript

Acc No Sequence Length Source
NM_013192 n/A n/A NCBI
NM_001025584 n/A n/A NCBI
NM_010606 n/A n/A NCBI
NM_001025590 n/A n/A NCBI
NM_001025585 n/A n/A NCBI
NM_002240 n/A n/A NCBI

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Ontology


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Interaction

G-Protein

The activation of GIRK channels is mediated by a pertussis toxin-sensitive G protein, via a direct membrane-delimited pathway without involving intracellular second messenger systems. The G-beta-gamma subunit plays an important physiological role in the activation by direct binding to multiple regions of GIRK channels (Huang [979]). Signaling via the G-protein-mediated pathway is regulated by a recently identified gene family, known to encode RGS proteins (regulators of G-protein signaling) (Druey [980]).

RGS4 reduces the basal GIRK1/GIRK2 current and strongly increases the percentage agonist-evoked K+ conductance. RGS4 reconstitutes the native gating kinetics by accelerating GIRK1/GIRK2 channel deactivation. Ulens [194]

GIRK2 but not GIRK3 can be activated by G protein subunits Gj3, and G-y2 in Xenopus oocytes. Kofuji [195]


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Protein


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Structure


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Distribution


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Expression

Kir3.2 is the predominant Kir3 subunit in the midbrain (Karschin et al., 1996 [983]; Chen et al., 1997 [984]; Murer et al., 1997 [985]; Schein et al., 1998 [986]).


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Functional

Kir3.2 ( = GIRK2) is important for opioid receptor transmission. Loetsch [973]

The importance of the strong expression of Kir3.2 in midbrain neurons is documented by the fact that a point mutation in the pore of the mouse Kir3.2 channel, leading to a loss of ion selectivity, results in the weaver (wv) phenotype. Such mice suffer from aberrant postnatal development and death of several classes of neurons including the dopaminergic neurons of the SNc (Liao et al., 1996 [981]; Surmeier et al., 1996 [987]).

The heterogeneously distributed Kir3.2 channel proteins could help to discriminate the dopaminergic neurons of ventral tegmental area and substantia nigra pars compacta. Eulitz [973]


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Kinetics


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Model


References

962

Wang C. et al. G protein {beta}{gamma} gating confers volatile anesthetic inhibition to Kir3 channels.
J. Biol. Chem., 2010 Dec 31 , 285 (41290-9).

976

Gerstin KM. et al. Mutation of KCNK5 or Kir3.2 potassium channels in mice does not change minimum alveolar anesthetic concentration.
Anesth. Analg., 2003 May , 96 (1345-9, table of contents).

978

Hatton WJ. et al. Kir3.1/3.2 encodes an I(KACh)-like current in gastrointestinal myocytes.
Am. J. Physiol. Gastrointest. Liver Physiol., 2000 Feb , 278 (G289-96).

980

982

Döring F. et al. Subunit interactions in the assembly of neuronal Kir3.0 inwardly rectifying K+ channels.
Mol. Cell. Neurosci., 1997 , 9 (194-206).

987

Surmeier DJ. et al. The weaver mutation of GIRK2 results in a loss of inwardly rectifying K+ current in cerebellar granule cells.
Proc. Natl. Acad. Sci. U.S.A., 1996 Oct 1 , 93 (11191-5).


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