Channelpedia

Kir3.2

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

Edit - History

Introduction

In mammals, G-protein-coupled inwardly rectifying potassium channels - such as Kir 3.2 - are composed of four subunits that are individual members of the Kir3 (formerly GIRK) family and form homomeric or heteromeric complexes (Liao et al., 1996 [981]; Wischmeyer et al., 1997 [982]).

KCNJ6 (also known as BIR1; GIRK2; KATP2; KCNJ7; GIRK-2; KATP-2; KIR3.2; hiGIRK2; MGC126596) encodes Kir3.2, an integral membrane protein, inward-rectifier type potassium channel, subfamily J, member 6. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, is controlled by G-proteins and may be involved in the regulation of insulin secretion by glucose. It associates with two other G-protein-activated potassium channels to form a heteromultimeric pore-forming complex.

http://www.ncbi.nlm.nih.gov/gene/3763


Experimental data


Edit

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


Edit

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

Edit

Ontology


Edit - History

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]


Edit

Protein


Edit

Structure


Edit

Distribution


Edit

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]).


Edit - History

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]


Edit

Kinetics


Edit

Model


References

962

Styer AM 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

Bradley KK 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).

982

Wischmeyer E 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).


Edit

Credits

To cite this page: [Contributors] Channelpedia https://channelpedia.epfl.ch/ionchannels/47/ , accessed on [date]