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

C.T. Bond, C. Ammala, R. Ashfield, T. A. Blair, F. Gribble, R. N. Khan, K. Lee, P. Proks, I. C. M. Rowe, H. Sakura, M. J. Ashford, J. P. Adelman, F. M. Ashcroft

    Research output: Contribution to journalArticle

    45 Citations (Scopus)

    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 rcK(ATP)(K-ATP-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 K-ATP-1 suggests that BIR1 is a subunit of a brain and beta-cell K-ATP 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.

    Original languageEnglish
    Pages (from-to)61-66
    Number of pages6
    JournalFEBS Letters
    Volume367
    Issue number1
    DOIs
    Publication statusPublished - 1995

    Keywords

    • PANCREATIC BETA-CELL
    • GLUCOSE
    • INWARD RECTIFIER
    • ATP
    • BIR1
    • K-CHANNEL
    • ATP-SENSITIVE K-CHANNEL

    Cite this

    Bond, C. T., Ammala, 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., & Ashcroft, F. M. (1995). Cloning and functional expression of the cDNA.-encoding an inwardly-rectifying potassium channel expressed in pancreatic beta-cells and in the brain. FEBS Letters, 367(1), 61-66. https://doi.org/10.1016/0014-5793(95)00497-W