Referenced in: none

Automatically associated channels: Kir1.1 , Kir2.1 , Kir2.2 , Kir2.3 , Kir3.1 , Kv1.4

Title: Molecular cloning and functional expression of a novel brain-specific inward rectifier potassium channel.

Authors: K Morishige, N Takahashi, A Jahangir, M Yamada, H Koyama, J S Zanelli, Y Kurachi

Journal, date & volume: FEBS Lett., 1994 Jun 13 , 346, 251-6

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/8013643

Abstract
We have cloned a novel brain-specific inward rectifier K+ channel from a mouse brain cDNA library and designated it MB-IRK3. The mouse brain cDNA library was screened using a fragment of the mouse macrophage inward rectifier K+ channel (IRK1) cDNA as a probe. The amino acid sequence of MB-IRK3 shares 61% and 64% identity to MB-IRK1 and RB-IRK2, respectively. Xenopus oocytes injected with cRNA derived from this clone expressed a potassium current which showed inward-rectifying channel characteristics similar to MB-IRK1 and RB-IRK2 currents, but distinct from ROMK1 or GIRK1 current. However, the single channel conductance of MB-IRK3 was approximately 10 pS with 140 mM extracellular K+, which was distinct from that of MB-IRK1 (20 pS). MB-IRK3 mRNA expressed specifically in the forebrain, which clearly differed from MB-IRK1 and RB-IRK2 mRNAs. These results indicate that members of the IRK family with distinct electrophysiological properties express differentially and may play heterogenous functional roles in brain functions.