Formation of intermediate-conductance calcium-activated potassium channels by interaction of Slack and Slo subunits

Nat Neurosci. 1998 Oct;1(6):462-9. doi: 10.1038/2176.


Large-conductance calcium-activated potassium channels (maxi-K channels) have an essential role in the control of excitability and secretion. Only one gene Slo is known to encode maxi-K channels, which are sensitive to both membrane potential and intracellular calcium. We have isolated a potassium channel gene called Slack that is abundantly expressed in the nervous system. Slack channels rectify outwardly with a unitary conductance of about 25-65 pS and are inhibited by intracellular calcium. However, when Slack is co-expressed with Slo, channels with pharmacological properties and single-channel conductances that do not match either Slack or Slo are formed. The Slack/Slo channels have intermediate conductances of about 60-180 pS and are activated by cytoplasmic calcium. Our findings indicate that some intermediate-conductance channels in the nervous system may result from an interaction between Slack and Slo channel subunits.

Publication types

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

MeSH terms

  • Amino Acid Sequence / genetics
  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins
  • Electric Conductivity
  • Intermediate-Conductance Calcium-Activated Potassium Channels
  • Isomerism
  • Large-Conductance Calcium-Activated Potassium Channels
  • Molecular Sequence Data
  • Nerve Tissue Proteins*
  • Potassium Channels / genetics
  • Potassium Channels / metabolism*
  • Potassium Channels / physiology*
  • Potassium Channels, Calcium-Activated*
  • Potassium Channels, Sodium-Activated


  • Caenorhabditis elegans Proteins
  • Intermediate-Conductance Calcium-Activated Potassium Channels
  • Large-Conductance Calcium-Activated Potassium Channels
  • Nerve Tissue Proteins
  • Potassium Channels
  • Potassium Channels, Calcium-Activated
  • Potassium Channels, Sodium-Activated
  • kcnt1 protein, rat
  • slo-1 protein, C elegans