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