Open AccessVoltage-controlled gating in a large conductance Ca 2+ -sensitive K + channel (hslo)
Author(s) -
Enrico Stefani,
Michela Ottolia,
Francesca Noceti,
Riccardo Olcese,
Martín Wallner,
Ramón Latorre,
Ligia Toro
Publication year - 1997
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.94.10.5427
Subject(s) - gating , conductance , depolarization , chemistry , ion channel , voltage , membrane potential , biophysics , voltage gated ion channel , ion , analytical chemistry (journal) , physics , biochemistry , receptor , organic chemistry , condensed matter physics , quantum mechanics , biology , chromatography
Large conductance calcium- and voltage-sensitive K+ (MaxiK) channels share properties of voltage- and ligand-gated ion channels. In voltage-gated channels, membrane depolarization promotes the displacement of charged residues contained in the voltage sensor (S4 region) inducing gating currents and pore opening. In MaxiK channels, both voltage and micromolar internal Ca2+ favor pore opening. We demonstrate the presence of voltage sensor rearrangements with voltage (gating currents) whose movement and associated pore opening is triggered by voltage and facilitated by micromolar internal Ca2+ concentration. In contrast to other voltage-gated channels, in MaxiK channels there is charge movement at potentials where the pore is open and the total charge per channel is 4–5 elementary charges.