Transplantable sites confer calcium sensitivity to BK channels

Nat Neurosci. 1999 May;2(5):416-21. doi: 10.1038/8077.


Both intracellular calcium and voltage activate Slo1, a high-conductance potassium channel, linking calcium with electrical excitability. Using molecular techniques, we created a calcium-insensitive variant of this channel gated by voltage alone. Calcium sensitivity was restored by adding back small portions of the carboxyl (C)-terminal 'tail' domain. Two separate regions of the tail independently conferred different degrees of calcium sensitivity; together, they restored essentially wild-type calcium dependence. These results suggest that, in the absence of calcium, the Slo1 tail inhibits voltage-dependent gating, and that calcium removes this inhibition. Slo1 may have evolved from an ancestral voltage-sensitive potassium channel represented by the core; the tail may represent the more recent addition of a calcium-dependent modulatory domain.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Calcium / physiology*
  • Ion Channel Gating
  • Large-Conductance Calcium-Activated Potassium Channels
  • Membrane Potentials / physiology
  • Molecular Sequence Data
  • Patch-Clamp Techniques
  • Potassium Channels / physiology*
  • Potassium Channels, Calcium-Activated*
  • Protein Structure, Tertiary
  • Transplantation*
  • Xenopus


  • Large-Conductance Calcium-Activated Potassium Channels
  • Potassium Channels
  • Potassium Channels, Calcium-Activated
  • Calcium