Concanavalin A modulates a potassium channel in cultured Aplysia neurons.
A novel 100 pS K(+)-selective ion channel is frequently observed in cell-attached membrane patches from cultured Aplysia neurons. The activity of this channel is moderately voltage-dependent, but channel openings are rare and brief even when the patch is strongly depolarized. However, the activity of the channel is increased dramatically by the addition of the lectin concanavalin A (Con A), to the patch pipette. The channel is also activated by Con A in the bathing medium, suggesting that the lectin's action is via an as yet unidentified intracellular second messenger. In the one single-channel patch studied, Con A had no effect on the channel mean open time; rather it decreased the average duration of the long closed times between bursts of openings. Thus Con A increases either the open probability of single channels, the number of functional channels in the patch, or both. The functional significance of the Con A-induced modulation of K+ channel activity remains to be determined.
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Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254.
Dagan
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Levitan
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D000818:Animals; D001048:Aplysia; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology*; D004553:Electric Conductivity; D008564:Membrane Potentials; D009474:Neurons / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism*; D013997:Time Factors
D015221:Potassium Channels; D003208:Concanavalin A