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The Ca2+-dependent gating mechanism of cloned BK channels from Drosophila (dSlo) was studied. Both a natural variant (A1/C2/E1/G3/IO) and a mutant (S942A) were expressed in Xenopus oocytes, and single-channel currents were recorded from excised patches of membrane. Stability plots were used to define stable segments of data. Unlike native BK channels from rat skeletal muscle in which increasing internal Ca2+ concentration (Cai2+) in the range of 5 to 30 microM increases mean open time, increasing Cai2+ in this range for dSlo had little effect on mean open time. However, further increases in Cai2+ to 300 or 3000 microM then typically increased dSlo mean open time. Kinetic schemes for the observed Ca2+-dependent gating kinetics of dSlo were evaluated by fitting two-dimensional dwell-time distributions using maximum likelihood techniques and by comparing observed dependency plots with those predicted by the models. Previously described kinetic schemes that largely account for the Ca2+-dependent kinetics of native BK channels from rat skeletal muscle did not adequately describe the Ca2+ dependence of dSlo. An expanded version of these schemes which, in addition to the Ca2+-activation steps, permitted a Ca2+-facilitated transition from each open state to a closed state, could approximate the Ca2+-dependent kinetics of dSlo, suggesting that Ca2+ may exert dual effects on gating.
Adelman,
Calcium-activated potassium channels expressed from cloned complementary DNAs.
1992,
Pubmed
,
Xenbase
Atkinson,
A component of calcium-activated potassium channels encoded by the Drosophila slo locus.
1991,
Pubmed
Blatz,
Quantitative description of three modes of activity of fast chloride channels from rat skeletal muscle.
1986,
Pubmed
Bowlby,
Kinetic variability and modulation of dSlo, a cloned calcium-dependent potassium channel.
1996,
Pubmed
,
Xenbase
Butler,
mSlo, a complex mouse gene encoding "maxi" calcium-activated potassium channels.
1993,
Pubmed
,
Xenbase
Ciorba,
Modulation of potassium channel function by methionine oxidation and reduction.
1997,
Pubmed
,
Xenbase
Colquhoun,
On the stochastic properties of single ion channels.
1981,
Pubmed
Cox,
Allosteric gating of a large conductance Ca-activated K+ channel.
1997,
Pubmed
,
Xenbase
Crouzy,
Yet another approach to the dwell-time omission problem of single-channel analysis.
1990,
Pubmed
DiChiara,
Distinct effects of Ca2+ and voltage on the activation and deactivation of cloned Ca(2+)-activated K+ channels.
1995,
Pubmed
,
Xenbase
DiChiara,
Redox modulation of hslo Ca2+-activated K+ channels.
1997,
Pubmed
,
Xenbase
Eigen,
New looks and outlooks on physical enzymology.
1968,
Pubmed
Esguerra,
Cloned Ca(2+)-dependent K+ channel modulated by a functionally associated protein kinase.
1994,
Pubmed
,
Xenbase
Ferguson,
Competitive Mg2+ block of a large-conductance, Ca(2+)-activated K+ channel in rat skeletal muscle. Ca2+, Sr2+, and Ni2+ also block.
1991,
Pubmed
Giangiacomo,
Functional reconstitution of the large-conductance, calcium-activated potassium channel purified from bovine aortic smooth muscle.
1995,
Pubmed
Gibb,
Expression of cloned receptor subunits produces multiple receptors.
1990,
Pubmed
,
Xenbase
Hamill,
Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches.
1981,
Pubmed
Hicks,
Ca2+-dependent inactivation of large conductance Ca2+-activated K+ (BK) channels in rat hippocampal neurones produced by pore block from an associated particle.
1998,
Pubmed
Hirschberg,
Gating of recombinant small-conductance Ca-activated K+ channels by calcium.
1998,
Pubmed
,
Xenbase
Hoshi,
Shaker potassium channel gating. I: Transitions near the open state.
1994,
Pubmed
,
Xenbase
Hudspeth,
Kinetic analysis of voltage- and ion-dependent conductances in saccular hair cells of the bull-frog, Rana catesbeiana.
1988,
Pubmed
Keller,
Two-dimensional probability density analysis of single channel currents from reconstituted acetylcholine receptors and sodium channels.
1990,
Pubmed
Krause,
Xenopus laevis oocytes contain endogenous large conductance Ca2(+)-activated K+ channels.
1996,
Pubmed
,
Xenbase
Lagrutta,
Functional differences among alternatively spliced variants of Slowpoke, a Drosophila calcium-activated potassium channel.
1994,
Pubmed
Laver,
Divalent cation block and competition between divalent and monovalent cations in the large-conductance K+ channel from Chara australis.
1992,
Pubmed
Magleby,
Identifying kinetic gating mechanisms for ion channels by using two-dimensional distributions of simulated dwell times.
1990,
Pubmed
Magleby,
Dependency plots suggest the kinetic structure of ion channels.
1992,
Pubmed
McManus,
Kinetic states and modes of single large-conductance calcium-activated potassium channels in cultured rat skeletal muscle.
1988,
Pubmed
McManus,
Calcium-activated potassium channels: regulation by calcium.
1991,
Pubmed
McManus,
Accounting for the Ca(2+)-dependent kinetics of single large-conductance Ca(2+)-activated K+ channels in rat skeletal muscle.
1991,
Pubmed
McManus,
Functional role of the beta subunit of high conductance calcium-activated potassium channels.
1995,
Pubmed
,
Xenbase
Methfessel,
The gating of single calcium-dependent potassium channels is described by an activation/blockade mechanism.
1982,
Pubmed
Mienville,
Mechanosensitive properties of BK channels from embryonic rat neuroepithelium.
1996,
Pubmed
Nelson,
Relaxation of arterial smooth muscle by calcium sparks.
1995,
Pubmed
Petersen,
Calcium-activated potassium channels and their role in secretion.
,
Pubmed
Reinhart,
Modulation of calcium-activated potassium channels from rat brain by protein kinase A and phosphatase 2A.
1991,
Pubmed
Robitaille,
Functional colocalization of calcium and calcium-gated potassium channels in control of transmitter release.
1993,
Pubmed
Rothberg,
High Ca2+ concentrations induce a low activity mode and reveal Ca2(+)-independent long shut intervals in BK channels from rat muscle.
1996,
Pubmed
Rothberg,
Two-dimensional components and hidden dependencies provide insight into ion channel gating mechanisms.
1997,
Pubmed
Rothberg,
Kinetic structure of large-conductance Ca2+-activated K+ channels suggests that the gating includes transitions through intermediate or secondary states. A mechanism for flickers.
1998,
Pubmed
Schreiber,
A novel calcium-sensing domain in the BK channel.
1997,
Pubmed
,
Xenbase
Sigworth,
Data transformations for improved display and fitting of single-channel dwell time histograms.
1987,
Pubmed
Silberberg,
Wanderlust kinetics and variable Ca(2+)-sensitivity of dSlo [correction of Drosophila], a large conductance CA(2+)-activated K+ channel, expressed in oocytes.
1996,
Pubmed
,
Xenbase
Stefani,
Voltage-controlled gating in a large conductance Ca2+-sensitive K+channel (hslo).
1997,
Pubmed
,
Xenbase
Thuringer,
Contrasting effects of intracellular redox couples on the regulation of maxi-K channels in isolated myocytes from rabbit pulmonary artery.
1997,
Pubmed
Wu,
A kinetic description of the calcium-activated potassium channel and its application to electrical tuning of hair cells.
1995,
Pubmed
