SK2 encodes the apamin-sensitive Ca(2+)-activated K(+) channels in the human leukemic T cell line, Jurkat

FEBS Lett. 2000 Mar 10;469(2-3):196-202. doi: 10.1016/s0014-5793(00)01236-9.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apamin / pharmacology*
  • Calcium / metabolism*
  • Cell Line
  • Humans
  • Jurkat Cells
  • Membrane Potentials / physiology
  • Patch-Clamp Techniques
  • Potassium Channel Blockers
  • Potassium Channels / metabolism*
  • Potassium Channels / physiology
  • Potassium Channels, Calcium-Activated*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Small-Conductance Calcium-Activated Potassium Channels
  • Transfection


  • KCNN2 protein, human
  • Potassium Channel Blockers
  • Potassium Channels
  • Potassium Channels, Calcium-Activated
  • Small-Conductance Calcium-Activated Potassium Channels
  • Apamin
  • Calcium