G protein-coupled inwardly rectifying potassium channel

potassium inwardly rectifying channel, subfamily J, member 3
Identifiers
SymbolKCNJ3
Alt. symbolsKir3.1, GIRK1, KGA
IUPHAR434
NCBI gene3760
HGNC6264
OMIM601534
RefSeqNM_002239
UniProtP48549
Other data
LocusChr. 2 q24.1
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StructuresSwiss-model
DomainsInterPro
potassium inwardly rectifying channel, subfamily J, member 6
Identifiers
SymbolKCNJ6
Alt. symbolsKCNJ7, Kir3.2, GIRK2, KATP2, BIR1, hiGIRK2
IUPHAR435
NCBI gene3763
HGNC6267
OMIM600877
RefSeqNM_002240
UniProtP48051
Other data
LocusChr. 21 q22.1
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StructuresSwiss-model
DomainsInterPro
potassium inwardly rectifying channel, subfamily J, member 9
Identifiers
SymbolKCNJ9
Alt. symbolsKir3.3, GIRK3
IUPHAR436
NCBI gene3765
HGNC6270
OMIM600932
RefSeqNM_004983
UniProtQ92806
Other data
LocusChr. 1 q23.2
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StructuresSwiss-model
DomainsInterPro
potassium inwardly rectifying channel, subfamily J, member 5
Identifiers
SymbolKCNJ5
Alt. symbolsKir3.4, CIR, KATP1, GIRK4
IUPHAR437
NCBI gene3762
HGNC6266
OMIM600734
RefSeqNM_000890
UniProtP48544
Other data
LocusChr. 11 q24
Search for
StructuresSwiss-model
DomainsInterPro

The G protein-coupled inwardly rectifying potassium channels (GIRKs) are a family of lipid-gated inward-rectifier potassium ion channels which are activated (opened) by the signaling lipid PIP2 and a signal transduction cascade starting with ligand-stimulated G protein-coupled receptors (GPCRs).[1][2] GPCRs in turn release activated G-protein βγ- subunits (Gβγ) from inactive heterotrimeric 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 membrane.[3] G protein-coupled inwardly rectifying potassium channels are a type of G protein-gated ion channels because of this direct interaction of G protein subunits with GIRK channels. The activation likely works by increasing the affinity of the channel for PIP2. In high concentration PIP2 activates the channel absent G-protein, but G-protein does not activate the channel absent PIP2.

GIRK1 to GIRK3 are distributed broadly in the central nervous system, where their distributions overlap.[4][5][6] GIRK4, instead, is found primarily in the heart.[7]

  1. ^ Dascal N (1997). "Signalling via the G protein-activated K+ channels". Cell. Signal. 9 (8): 551–73. doi:10.1016/S0898-6568(97)00095-8. PMID 9429760.
  2. ^ Yamada M, Inanobe A, Kurachi Y (December 1998). "G protein regulation of potassium ion channels". Pharmacological Reviews. 50 (4): 723–60. PMID 9860808.
  3. ^ Cite error: The named reference GIRK was invoked but never defined (see the help page).
  4. ^ Kobayashi T, Ikeda K, Ichikawa T, Abe S, Togashi S, Kumanishi T (March 1995). "Molecular cloning of a mouse G-protein-activated K+ channel (mGIRK1) and distinct distributions of three GIRK (GIRK1, 2 and 3) mRNAs in mouse brain". Biochem. Biophys. Res. Commun. 208 (3): 1166–73. doi:10.1006/bbrc.1995.1456. PMID 7702616.
  5. ^ Karschin C, Dissmann E, Stühmer W, Karschin A (June 1996). "IRK(1-3) and GIRK(1-4) inwardly rectifying K+ channel mRNAs are differentially expressed in the adult rat brain". J. Neurosci. 16 (11): 3559–70. doi:10.1523/JNEUROSCI.16-11-03559.1996. PMC 6578832. PMID 8642402.
  6. ^ Chen SC, Ehrhard P, Goldowitz D, Smeyne RJ (December 1997). "Developmental expression of the GIRK family of inward rectifying potassium channels: implications for abnormalities in the weaver mutant mouse". Brain Res. 778 (2): 251–64. doi:10.1016/S0006-8993(97)00896-2. PMID 9459542. S2CID 13599513.
  7. ^ Cite error: The named reference pmid7877685 was invoked but never defined (see the help page).