Structural requirements for rapid inactivation and voltage dependence in splice variants of lobster Shaker potassium channels.
We studied the properties of currents generated in Xenopus oocytes by nine splice variants of the spiny lobster Shaker gene. These isoforms differ in their amino termini and in the P-loop region of the pore. Both the voltage dependence and kinetic properties of the currents varied significantly, depending on which amino terminus was present. A cluster of net positive charges at the N-terminus was not necessary for rapid inactivation: negatively charged N-termini also inactivated rapidly. There was no obvious correlation between N-terminus length and inactivation rate. These N-terminal effects were additive with a separate set of voltage and kinetic properties controlled by the two alternative P-loop exons.
French
L B
LB
Department of Neurobiology and Behavior, Cornell University, Ithaca, New York, USA. lfrench@allegheny.edu
Singh
A
A
Luik
R
R
Harris-Warrick
R M
RM
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D004594:Electrophysiology; D005260:Female; D015640:Ion Channel Gating; D007700:Kinetics; D008969:Molecular Sequence Data; D009865:Oocytes / Q000166:cytology / Q000378:metabolism*; D033521:Palinuridae / Q000502:physiology*; D015221:Potassium Channels / Q000235:genetics / Q000502:physiology*; D020033:Protein Isoforms; D017384:Sequence Deletion; D051637:Shaker Superfamily of Potassium Channels; D014982:Xenopus laevis
D015221:Potassium Channels; D020033:Protein Isoforms; D051637:Shaker Superfamily of Potassium Channels