High impact information on Kcnj12

• Targeted disruption of Kir2.1 and Kir2.2 genes reveals the essential role of the inwardly rectifying K(+) current in K(+)-mediated vasodilation [1].
• An increase in the extracellular K(+) concentration from 6 to 15 mmol/L caused Ba(2+)-sensitive dilations in pressurized cerebral arteries from control and Kir2.2 mice [1].
• Expression of Kir2.2 in polarized epithelial cells resulted in targeting of the channels to the basolateral membrane and co-localization with SAP97 and CASK, whereas a dominant interfering form of CASK caused the channels to mislocalize [2].
• In the brain, the abundance of mRNA for MB-IRK2 was much higher in cerebellum than in forebrain and vice versa in the case of MB-IRK1 [3].
• We have cloned a second class of inward rectifier potassium channels, designated MB-IRK2, from a mouse brain cDNA library [3].

Biological context of Kcnj12

• Owing to their localization on RNO10 and their involvement in a similar pathology in human and mouse, Myo15 and Kcnj12 can be regarded as candidate genes for the deafblind phenotype of the LEW-ci2 rat [4].
• Assignment of the murine inward rectifier potassium channel Irk2 (Kir2.2) gene to the central region of mouse chromosome 11 [5].
• Kir2.2-/- exhibited a smaller increase in tidal volume and minute ventilation volume than the FVB mouse in response to hypercapnic challenge on days 14-15 [6].
• We designated them mouse brain (MB)- IRK1, MB-IRK2, and MB-IRK3, based on their amino acid sequences and the electrophysiological properties of currents expressed in Xenopus oocytes [7].

Anatomical context of Kcnj12

• Xenopus oocytes injected with cRNA derived from MB-IRK2 expressed a K+ current, which showed inward rectifying channel characteristics similar to the MB-IRK1 current [3].
• Northern blot analysis revealed the mRNA for MB-IRK2 to be expressed in forebrain, cerebellum, heart, kidney, and skeletal muscle [3].
• Their distribution patterns in the brain were, however, quite divergent: IRK2 mRNA was detected extremely high in granule cells of cerebellum, relatively high in motor trigeminal nucleus and moderate in olfactory bulb, piriform cortex, cerebral cortex, CA1 through CA3 regions of hippocampus, dentate gyrus and pontine nucleus [8].

Associations of Kcnj12 with chemical compounds

• Both the Kir2.1 and Kir2.2 currents recorded from inside-out patches exhibited outward transients similar to those of ventricular I(K1) in the presence of 5-10 microM spermine and 0.6-1.1 mM Mg(2+), and their amplitudes were diminished by increasing the spermine or spermidine concentrations [9].

Other interactions of Kcnj12

• The single channel recordings revealed, however, that the unitary conductance of MB-IRKI was approximately 22pS; MB-IRK2, approximately 34pS; and MB-IRK3, approximately 12pS [7].

Analytical, diagnostic and therapeutic context of Kcnj12

• We also examined developmental changes in m-RNA expression of Kir2.2 in the brainstem of the FVB mouse using quantitative real-time PCR assay [6].

References