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SK2 encodes the apamin‐sensitive Ca 2+ ‐activated K + channels in the human leukemic T cell line, Jurkat
Author(s) -
Jäger Heike,
Adelman John P.,
Grissmer Stephan
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)01236-9
Subject(s) - jurkat cells , apamin , sk channel , transfection , microbiology and biotechnology , biology , stimulation , ion channel , potassium channel , charybdotoxin , cell culture , patch clamp , biophysics , t cell , electrophysiology , biochemistry , endocrinology , genetics , neuroscience , receptor , immune system
T cells express two different types of voltage‐independent Ca 2+ ‐activated K + channels with small (SK) and intermediate (IK) conductance that serve important roles in the activation of T lymphocytes. In contrast to the IK channels from T lymphocytes which are upregulated upon mitogen stimulation, SK channels of Jurkat T cells, a human leukemic T cell line, are constitutively expressed even in the absence of mitogenic stimulation. We have used patch‐clamp recordings from transfected or injected mammalian cells to show that the cloned SK2 channel demonstrates the biophysical and pharmacological properties of the majority of K(Ca) channels in Jurkat T cells. The cloned and native channels are voltage‐independent, Ca 2+ ‐activated, apamin‐sensitive, show an equivalent voltage‐dependent Ba 2+ block and possess a similar ion selectivity. In addition, we used the polymerase chain reaction to demonstrate the presence of SK2 mRNA in Jurkat T cells, whereas SK3 transcripts encoding the other cloned apamin‐sensitive SK channel were not detected. These data suggest that the voltage‐independent apamin‐sensitive K(Ca) channel in Jurkat T cells represents the recently cloned SK2 channel.

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