Title: A novel ATP-dependent inward rectifier potassium channel expressed predominantly in glial cells.

Authors: T Takumi, T Ishii, Y Horio, K Morishige, N Takahashi, M Yamada, T Yamashita, H Kiyama, K Sohmiya, S Nakanishi

Journal, date & volume: J. Biol. Chem., 1995 Jul 7 , 270, 16339-46

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/7608203

Abstract
We have isolated a novel inward rectifier K+ channel predominantly expressed in glial cells of the central nervous system. Its amino acid sequence exhibited 53% identity with ROMK1 and approximately 40% identity with other inward rectifier K+ channels. Xenopus oocytes injected with cRNA derived from this clone expressed a K+ current, which showed classical inward rectifier K+ channel characteristics. Intracellular Mg.ATP was required to sustain channel activity in excised membrane patches, which is consistent with a Walker type-A ATP-binding domain on this clone. We designate this new clone as KAB-2 (the second type of inward rectifying K+ channel with an ATP-binding domain). In situ hybridization showed KAB-2 mRNA to be expressed predominantly in glial cells of the cerebellum and forebrain. This is the first description of the cloning of a glial cell inward rectifier potassium channel, which may be responsible for K+ buffering action of glial cells in the brain.