- G protein-coupled inwardly-rectifying potassium channel
protein
Name = potassium inwardly-rectifying channel, subfamily J, member 3
caption =
width =
HGNCid = 6264
Symbol =KCNJ3
AltSymbols = Kir3.1, GIRK1, KGA
EntrezGene = 3760
OMIM = 601534
RefSeq = NM_002239
UniProt = P48549
PDB =
ECnumber =
Chromosome = 2
Arm = q
Band = 24.1
LocusSupplementaryData = protein
Name = potassium inwardly-rectifying channel, subfamily J, member 6
caption =
width =
HGNCid = 6267
Symbol =KCNJ6
AltSymbols = KCNJ7, Kir3.2, GIRK2, KATP2, BIR1, hiGIRK2
EntrezGene = 3763
OMIM = 600877
RefSeq = NM_002240
UniProt = P48051
PDB =
ECnumber =
Chromosome = 21
Arm = q
Band = 22.1
LocusSupplementaryData = protein
Name = potassium inwardly-rectifying channel, subfamily J, member 9
caption =
width =
HGNCid = 6270
Symbol =KCNJ9
AltSymbols = Kir3.3, GIRK3
EntrezGene = 3765
OMIM = 600932
RefSeq = NM_004983
UniProt = Q92806
PDB =
ECnumber =
Chromosome = 1
Arm = q
Band = 23.2
LocusSupplementaryData = protein
Name = potassium inwardly-rectifying channel, subfamily J, member 5
caption =
width =
HGNCid = 6266
Symbol =KCNJ5
AltSymbols = Kir3.4, CIR, KATP1, GIRK4
EntrezGene = 3762
OMIM = 600734
RefSeq = NM_000890
UniProt = P48544
PDB =
ECnumber =
Chromosome = 11
Arm = q
Band = 24
LocusSupplementaryData = The G protein-coupled inwardly-rectifying potassium channels (GIRKs) are a family ofinward-rectifier potassium ion channel s which are activated (opened) via asignal transduction cascade starting with ligand stimulatedG protein-coupled receptor s (GPCRs).cite journal | author = Dascal N | title = Signalling via the G protein-activated K+ channels | journal = Cell. Signal. | volume = 9 | issue = 8 | pages = 551–73 | year = 1997 | pmid = 9429760 | issn = | doi = 10.1016/S0898-6568(97)00095-8 ] cite journal | author = Yamada M, Inanobe A, Kurachi Y | title = G protein regulation of potassium ion channels | journal = Pharmacol. Rev. | volume = 50 | issue = 4 | pages = 723–60 | year = 1998 | pmid = 9860808 | doi = | issn = | url = http://pharmrev.aspetjournals.org/cgi/content/abstract/50/4/723 ] GPCRs in turn release activated G-protein βγ subunits (Gβγ) from inactiveheterotrimeric G protein complexes (Gαβγ). Finally the Gβγ dimeric protein interacts with GIRK channels to open them so that they become permeable to potassium ions resulting in hyperpolarization of the cell.ubtypes
Examples
A wide variety of G-protein coupled receptors activate GIRKs including the M2-muscarinic, A1-adenosine, α2-adrenergic, D2-dopamine, μ- δ-, and κ-opioid, 5-HT1A serotonin, somatostatin, galanin, m-Glu, GABAB, and sphingosine-1-phosphate receptors.
Examples of GIRKs include a subset of potassium channels in the heart which when activated by
parasympathetic signals such asacetylcholine through M2 muscarinic receptors, causes an outward current of potassium which slows down theheart rate .cite journal | author = Kunkel MT, Peralta EG | title = Identification of domains conferring G protein regulation on inward rectifier potassium channels | journal = Cell | volume = 83 | issue = 3 | pages = 443–9 | year = 1995 | pmid = 8521474 | doi = 10.1016/0092-8674(95)90122-1 | issn = ] cite journal | author = Wickman K, Krapivinsky G, Corey S, Kennedy M, Nemec J, Medina I, Clapham DE | title = Structure, G protein activation, and functional relevance of the cardiac G protein-gated K+ channel, IKACh | journal = Ann. N. Y. Acad. Sci. | volume = 868 | issue = | pages = 386–98 | year = 1999 | pmid = 10414308 | doi = | issn = | url = http://www.annalsnyas.org/cgi/content/abstract/868/1/386 ] These are called "muscarinic potassium channels" (IKACh) and are heterotetramers comprised of two GIRK1 and two GIRK4 subunits.cite journal | author = Krapivinsky G, Gordon EA, Wickman K, Velimirović B, Krapivinsky L, Clapham DE | title = The G-protein-gated atrial K+ channel IKACh is a heteromultimer of two inwardly rectifying K+-channel proteins | journal = Nature | volume = 374 | issue = 6518 | pages = 135–41 | year = 1995 | pmid = 7877685 | doi = 10.1038/374135a0 | issn = ] cite journal | author = Corey S, Krapivinsky G, Krapivinsky L, Clapham DE | title = Number and stoichiometry of subunits in the native atrial G-protein-gated K+ channel, IKACh | journal = J. Biol. Chem. | volume = 273 | issue = 9 | pages = 5271–8 | year = 1998 | pmid = 9478984 | doi = 10.1074/jbc.273.9.5271 | issn = ]References
External links
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