Cloning and functional expression of the cDNA encoding an inwardly-rectifying potassium channel expressed in pancreatic β-cells and in the brain

Bond, C.T. et al. (1995) Cloning and functional expression of the cDNA encoding an inwardly-rectifying potassium channel expressed in pancreatic β-cells and in the brain. FEBS Letters, 367(1), pp. 61-66. (doi: 10.1016/0014-5793(95)00497-W) (PMID:7601286)

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Abstract

A cDNA clone encoding an inwardly-rectifying K-channel (BIR1) was isolated from insulinoma cells. The predicted amino acid sequence shares 72% identity with the cardiac ATP-sensitive K-channel rcKATP (KATP-1; [6]). The mRNA is expressed in the brain and insulinoma cells. Heterologous expression in Xenopus oocytes produced currents which were K+-selective, time-independent and showed inward rectification. The currents were blocked by external barium and caesium, but insensitive to tolbutamide and diazoxide. In inside-out patches, channel activity was not blocked by 1 mM internal ATP. The sequence homology with KATP-1 suggests that BIR1 is a subunit of a brain and β-cell KATP channel. However, pharmacological differences and the lack of ATP-sensitivity, suggest that if, this is the case, heterologous subunits must exert strong modulatory influences on the native channel.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Rowe, Dr Iain
Authors: Bond, C.T., Ämmälä, C., Ashfield, R., Blair, T.A., Gribble, F., Khan, R.N., Lee, K., Proks, P., Rowe, I.C.M., Sakura, H., Ashford, M.J., Adelman, J.P., and Ashcroft, F.M.
College/School:College of Medical Veterinary and Life Sciences > School of Life Sciences
Journal Name:FEBS Letters
Publisher:Federation of European Biochemical Societies
ISSN:0014-5793
ISSN (Online):1873-3468

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