Calcium-activated potassium channels expressed from cloned complementary DNAs

John P. Adelman, Ke Zhong Shen, Michael P. Kavanaugh, Robin A. Warren, Yan Na Wu, Armando Lagrutta, Chris T. Bond, R. Alan North

Research output: Contribution to journalArticlepeer-review

452 Scopus citations


Calcium-activated potassium channels were expressed in Xenopus oocytes by injection of RNA transcribed in vitro from complementary DNAs derived from the slo locus of Drosophila melanogaster. Many cDNAs were found that encode closely related proteinsof about 1200 aa. The predicted sequences of these proteins differ by the substitution of blocks of amino acids at five identified positions within the putative intracellular region between residues 327 and 797. Excised inside-out membrane patches showed potassium channel openings only with micromolar calcium present at the cytoplasmic side; activity increased steeply both with depolarization and with increasing calcium concentration. The single-channel conductance was 126 pS with symmetrical potassium concentrations. The mean open time of the channels was clearly different for channels having different subsituent blocks of amino acids. The results suggest that alternative splicing gives rise to a large family of functionally diverse, calcium-activated potassium channels.

Original languageEnglish
Pages (from-to)209-216
Number of pages8
Issue number2
StatePublished - Aug 1992


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