Formation of intermediate-conductance calcium-activated potassium channels by interaction of Slack and Slo subunits.
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.
Joiner
W J
WJ
Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Tang
M D
MD
Wang
L Y
LY
Dworetzky
S I
SI
Boissard
C G
CG
Gan
L
L
Gribkoff
V K
VK
Kaczmarek
L K
LK
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D004553:Electric Conductivity; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; D007536:Isomerism; D051036:Large-Conductance Calcium-Activated Potassium Channels; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D024681:Potassium Channels, Calcium-Activated; D000081033:Potassium Channels, Sodium-Activated
D029742:Caenorhabditis elegans Proteins; D051660:Intermediate-Conductance Calcium-Activated Potassium Channels; D051036:Large-Conductance Calcium-Activated Potassium Channels; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; D024681:Potassium Channels, Calcium-Activated; D000081033:Potassium Channels, Sodium-Activated; C000626167:kcnt1 protein, rat; C494845:slo-1 protein, C elegans