Alternative titles; symbols
HGNC Approved Gene Symbol: KCNJ9
Cytogenetic location: 1q23.2 Genomic coordinates (GRCh38): 1:160,081,538-160,090,563 (from NCBI)
Inwardly rectifying K+ channels control resting membrane potential and initiation of action potentials. G protein-activated K+ channels, such as KCNJ9, regulate heart beat and neuronal firing rate (summary by Vaughn et al., 2000).
Lesage et al. (1994) reported the cloning of a mouse G protein-coupled inward rectifier potassium channel, which they designated mbGIRK3. Like other members of the family, the predicted 376-amino acid protein contains 2 hydrophobic membrane-spanning domains and a pore-forming domain. It is about 65% identical to IRK1 (600681) and 50% with ROMK1 (600359) and GIRK1 (601534). Highest expression was found in brain.
Using RT-PCR, Vaughn et al. (2000) found high KCNJ9 expression in adult and fetal human brain. Expression was also detected in pituitary, small intestine, testis, fat, kidney, skeletal muscle, smooth muscle, and pancreas, but not in ovary, placenta, spleen, stomach, thyroid gland, adrenal gland, mammary gland, heart, and liver.
Vaughn et al. (2000) determined that the KCNJ9 gene contains 3 exons and spans approximately 7.6 kb. Exon 1 is noncoding. The promoter region lacks canonical TATA and CAAT boxes, but it has an ETV4 (600711) enhancer element and binding sites for transcription factors that regulate gene expression in beta cells and muscle cells.
Lesage et al. (1995) mapped the human KCNJ9 gene to chromosome 1q21-q23 by in situ hybridization.
Gross (2014) mapped the KCNJ9 gene to chromosome 1q23.2 based on an alignment of the KCNJ9 sequence (GenBank AF193615) with the genomic sequence (GRCh37).
Pravetoni and Wickman (2008) found that Girk3 -/- mice demonstrated normal open-field motor activity and habituation, anxiety-related behavior, motor coordination and ataxia, and operant performance. They noted that other investigators had found that Girk3 -/- mice displayed altered responses to cocaine, morphine, and heat application.
Gross, M. B. Personal Communication. Baltimore, Md. 7/17/2014.
Lesage, F., Duprat, F., Fink, M., Guillemare, E., Coppola, T., Lazdunski, M., Hugnot, J.-P. Cloning provides evidence for a family of inward rectifier and G-protein coupled K(+) channels in the brain. FEBS Lett. 353: 37-42, 1994. [PubMed: 7926018] [Full Text: https://doi.org/10.1016/0014-5793(94)01007-2]
Lesage, F., Fink, M., Barhanin, J., Lazdunski, M., Mattei, M.-G. Assignment of human G-protein-coupled inward rectifier K(+) channel homolog GIRK3 gene to chromosome 1q21-q23. Genomics 29: 808-809, 1995. [PubMed: 8575783] [Full Text: https://doi.org/10.1006/geno.1995.9928]
Pravetoni, M., Wickman, K. Behavioral characterization of mice lacking GIRK/Kir3 channel subunits. Genes Brain Behav. 7: 523-531, 2008. [PubMed: 18194467] [Full Text: https://doi.org/10.1111/j.1601-183X.2008.00388.x]
Vaughn, J., Wolford, J. K., Prochazka, M., Permana, P. A. Genomic structure and expression of human KCNJ9 (Kir3.3/GIRK3). Biochem. Biophys. Res. Commun. 274: 302-309, 2000. [PubMed: 10913335] [Full Text: https://doi.org/10.1006/bbrc.2000.3136]