| 词条 | G protein-coupled inwardly-rectifying potassium channel | |||||||||||||||
| 释义 |
| Name = potassium inwardly-rectifying channel, subfamily J, member 3 | caption = | image = | width = | HGNCid = 6264 | Symbol = KCNJ3 | AltSymbols = Kir3.1, GIRK1, KGA | IUPHAR_id = yes | EntrezGene = 3760 | OMIM = 601534 | RefSeq = NM_002239 | UniProt = P48549 | PDB = | ECnumber = | Chromosome = 2 | Arm = q | Band = 24.1 | LocusSupplementaryData = }}{{infobox protein | Name = potassium inwardly-rectifying channel, subfamily J, member 6 | caption = | image = | width = | HGNCid = 6267 | Symbol = KCNJ6 | AltSymbols = KCNJ7, Kir3.2, GIRK2, KATP2, BIR1, hiGIRK2 | IUPHAR_id = yes | EntrezGene = 3763 | OMIM = 600877 | RefSeq = NM_002240 | UniProt = P48051 | PDB = | ECnumber = | Chromosome = 21 | Arm = q | Band = 22.1 | LocusSupplementaryData = }}{{infobox protein | Name = potassium inwardly-rectifying channel, subfamily J, member 9 | caption = | image = | width = | HGNCid = 6270 | Symbol = KCNJ9 | AltSymbols = Kir3.3, GIRK3 | IUPHAR_id = yes | EntrezGene = 3765 | OMIM = 600932 | RefSeq = NM_004983 | UniProt = Q92806 | PDB = | ECnumber = | Chromosome = 1 | Arm = q | Band = 23.2 | LocusSupplementaryData = }}{{infobox protein | Name = potassium inwardly-rectifying channel, subfamily J, member 5 | caption = | image = | width = | HGNCid = 6266 | Symbol = KCNJ5 | AltSymbols = Kir3.4, CIR, KATP1, GIRK4 | IUPHAR_id = yes | 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 of inward-rectifier potassium ion channels which are activated (opened) via 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 activation of GIRK channels by G protein subunits. GIRK1 to GIRK3 are distributed broadly in the central nervous system, where their distributions overlap.[3][4][5] GIRK4, instead, is found primarily in the heart.[7] Subtypes
ExamplesA 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, TAAR1, CB1 and CB2, and sphingosine-1-phosphate receptors.[2][6][7] Examples of GIRKs include a subset of potassium channels in the heart, which, when activated by parasympathetic signals such as acetylcholine through M2 muscarinic receptors, causes an outward current of potassium, which slows down the heart rate.[8][9] These are called muscarinic potassium channels (IKACh) and are heterotetramers composed of two GIRK1 and two GIRK4 subunits.[10][11] References1. ^{{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| doi = 10.1016/S0898-6568(97)00095-8 }} 2. ^1 {{cite journal |vauthors=Yamada M, Inanobe A, Kurachi Y | title = G protein regulation of potassium ion channels | journal = Pharmacological Reviews | volume = 50 | issue = 4 | pages = 723–60 |date=December 1998 | pmid = 9860808 | doi = | url = http://pharmrev.aspetjournals.org/cgi/pmidlookup?view=long&pmid=9860808}} 3. ^{{cite journal |vauthors=Kobayashi T, Ikeda K, Ichikawa T, Abe S, Togashi S, Kumanishi T | title = 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 | journal = Biochem. Biophys. Res. Commun. | volume = 208 | issue = 3 | pages = 1166–73 |date=March 1995 | pmid = 7702616 | doi = 10.1006/bbrc.1995.1456| url = }} 4. ^{{cite journal |vauthors=Karschin C, Dissmann E, Stühmer W, Karschin A | title = IRK(1-3) and GIRK(1-4) inwardly rectifying K+ channel mRNAs are differentially expressed in the adult rat brain | journal = J. Neurosci. | volume = 16 | issue = 11 | pages = 3559–70 |date=June 1996 | pmid = 8642402 | doi = | url = }} 5. ^{{cite journal |vauthors=Chen SC, Ehrhard P, Goldowitz D, Smeyne RJ | title = Developmental expression of the GIRK family of inward rectifying potassium channels: implications for abnormalities in the weaver mutant mouse | journal = Brain Res. | volume = 778 | issue = 2 | pages = 251–64 |date=December 1997 | pmid = 9459542 | doi = 10.1016/S0006-8993(97)00896-2| url = }} 6. ^1 {{cite journal |vauthors=Ledonne A, Berretta N, Davoli A, Rizzo GR, Bernardi G, Mercuri NB | title = Electrophysiological effects of trace amines on mesencephalic dopaminergic neurons | journal = Front Syst Neurosci | volume = 5 | issue = | pages = 56 | year = 2011 | pmid = 21772817 | pmc = 3131148 | doi = 10.3389/fnsys.2011.00056 | quote = inhibition of firing due to increased release of dopamine; (b) reduction of D2 and GABAB receptor-mediated inhibitory responses (excitatory effects due to disinhibition); and (c) a direct TA1 receptor-mediated activation of GIRK channels which produce cell membrane hyperpolarization.}} 7. ^{{cite journal | vauthors = Svízenská I, Dubový P, Sulcová A | title =Cannabinoid Receptors 1 and 2 (CB1 and CB2), Their Distribution, Ligands and Functional Involvement in Nervous System Structures — A Short Review | journal = Pharmacology Biochemistry and Behavior | volume = 90 | issue = 4 | pages = 501–11 | date = October 2008 | pmid = 18584858 | doi = 10.1016/j.pbb.2008.05.010 }} 8. ^{{cite journal |vauthors=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 }} 9. ^{{cite journal |vauthors=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 = 1| pages = 386–98 | year = 1999 | pmid = 10414308 | doi = 10.1111/j.1749-6632.1999.tb11300.x| url = http://www.annalsnyas.org/cgi/content/abstract/868/1/386 }} 10. ^1 {{cite journal |vauthors=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 }} 11. ^{{cite journal |vauthors=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 }} External links
1 : Ion channels |
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