Kir3.3 channels
| Channel name | Kir3.3 |
| Description | G-protein gated, inwardly rectifying potassium channel Kir3.3 subunit |
| Other names | GIRK3 |
| Molecular information | Human (KCNJ9): 393aa, Locus ID: 3765, GenBank: AF193615, NM_004983, PMID: 8575783,1 chr. 1q21-23 |
| Rat (Kcnj9): 393aa, Locus ID: 116560, GenBank: L77929, NM_053834, PMID: 8670302,2 chr. 13q24 | |
| Mouse (Kcnj9): 393aa, Locus ID: 16524, GenBank: AF130860, NM_008429, PMID: 7926018,3 103410344 | |
| Associated subunits | Kir3.1, Kir3.2 |
| Functional assays | Voltage-clamp |
| Current | IGIRK |
| Conductance | 39pS for Kir3.3/Kir3.1; 31pS for Kir3.3/Kir3.2 |
| Ion selectivity | K+ |
| Activation | Gβγ subunits at 1 to 50 nM |
| Inactivation | Not established |
| Activators | Gβγ subunits, modified by PIP2, sodium |
| Gating inhibitors | Gα subunits by binding Gβγ subunits |
| Blockers | None |
| Radioligands | None |
| Channel distribution | Brain |
| Physiological functions | Receptor-dependent hyperpolarization of membrane potential |
| Mutations and pathophysiology | Candidate gene for type 2 diabetes mellitus |
| Pharmacological significance | Not established |
aa, amino acids; chr., chromosome.
↵1. Lesage F, Fink M, Barhanin J, Lazdunski M, and Matti MG (1995) Assignment of human G-protein-coupled inward rectifier K+ channel homolog GIRK3 gene to chromosome 1q21-q23. Genomics 29:808-809
↵2. Dissmann E, Wischmeyer E, Spauschus A, Karschin C, and Karschin A (1996) Cloning and functional expression and cellular localization of a rat brain G protein-activated K+ inward rectifier GIRK3. Biochem Biophys Res Commun 223:474-479
↵3. Lesage F, Duprat F, Fink M, Guillemare E, Coppola T, Lazdunski M, and Hugnot JP (1994) Cloning provides evidence for a family of inward rectifier and G-protein coupled K+ channels in the brain. FEBS Lett 353:37-42
↵4. Jelacic T, Stephen SM, and Clapham DE (1999) Functional expression and characterization of G-protein-gated inwardly rectifying K+ channels containing GIRK3. J Membr Biol 169:123-129