G protein-coupled inwardly-rectifying potassium channel
| potassium inwardly-rectifying channel, subfamily J, member 3 | |
|---|---|
| Identifiers | |
| Symbol | KCNJ3 |
| Alt. symbols | Kir3.1, GIRK1, KGA |
| IUPHAR | 434 |
| Entrez | 3760 |
| HUGO | 6264 |
| OMIM | 601534 |
| RefSeq | NM_002239 |
| UniProt | P48549 |
| Other data | |
| Locus | Chr. 2 q24.1 |
| potassium inwardly-rectifying channel, subfamily J, member 6 | |
|---|---|
| Identifiers | |
| Symbol | KCNJ6 |
| Alt. symbols | KCNJ7, Kir3.2, GIRK2, KATP2, BIR1, hiGIRK2 |
| IUPHAR | 435 |
| Entrez | 3763 |
| HUGO | 6267 |
| OMIM | 600877 |
| RefSeq | NM_002240 |
| UniProt | P48051 |
| Other data | |
| Locus | Chr. 21 q22.1 |
| potassium inwardly-rectifying channel, subfamily J, member 9 | |
|---|---|
| Identifiers | |
| Symbol | KCNJ9 |
| Alt. symbols | Kir3.3, GIRK3 |
| IUPHAR | 436 |
| Entrez | 3765 |
| HUGO | 6270 |
| OMIM | 600932 |
| RefSeq | NM_004983 |
| UniProt | Q92806 |
| Other data | |
| Locus | Chr. 1 q23.2 |
| potassium inwardly-rectifying channel, subfamily J, member 5 | |
|---|---|
| Identifiers | |
| Symbol | KCNJ5 |
| Alt. symbols | Kir3.4, CIR, KATP1, GIRK4 |
| IUPHAR | 437 |
| Entrez | 3762 |
| HUGO | 6266 |
| OMIM | 600734 |
| RefSeq | NM_000890 |
| UniProt | P48544 |
| Other data | |
| Locus | Chr. 11 q24 |
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). 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. 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. GIRK4, instead, is found primarily in the heart.
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, TAAR1, and sphingosine-1-phosphate receptors.
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