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

• Published in: Nature neuroscience Vol. 1; no. 6; pp. 462 - 469
• Main Authors: Kaczmarek, Leonard K, Joiner, William J, Tang, Michael D, Wang, Lu-Yang, Dworetzky, Steven I, Boissard, Christopher G, Gan, Li, Gribkoff, Valentin K
• Format: Journal Article
• Language: English
• Published: United States 01.10.1998
• Subjects: 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
• ISSN: 1097-6256; 1546-1726
• 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.