ArticleThe Journal of general physiology2010
Allosteric mechanism of Ca2+ activation and H+-inhibited gating of the MthK K+ channel.
Article in The Journal of general physiology, 2010. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 20 papers.
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Who cites it
20 citing papers in PubMed.
- Interactions between selectivity filter and pore helix control filter gating in the MthK channel.The Journal of general physiology · 2023Article
- Forces and energetics of the canonical tetrameric cation channel gating.Proceedings of the National Academy of Sciences of the United States of America · 2023Article
- Vesicular and Planar Membranes of Archaea Lipids: Unusual Physical Properties and Biomedical Applications.International journal of molecular sciences · 2022Review
- Certain, but Not All, Tetraether Lipids from the Thermoacidophilic ArchaeonInternational journal of molecular sciences · 2021Article
- Molecular Mechanisms for Bacterial Potassium Homeostasis.Journal of molecular biology · 2021Review
- Article
- Selectivity filter ion binding affinity determines inactivation in a potassium channel.Proceedings of the National Academy of Sciences of the United States of America · 2020Article
- Polyamine block of MthK potassium channels.The Journal of general physiology · 2020Article
- Polyamine blockade and binding energetics in the MthK potassium channel.The Journal of general physiology · 2020Article
- Article
- Activation of a nucleotide-dependent RCK domain requires binding of a cation cofactor to a conserved site.eLife · 2019Article
- Permeating disciplines: Overcoming barriers between molecular simulations and classical structure-function approaches in biological ion transport.Biochimica et biophysica acta. Biomembranes · 2018Review
- Stopped-Flow Fluorometric Ion Flux Assay for Ligand-Gated Ion Channel Studies.Methods in molecular biology (Clifton, N.J.) · 2018Article
- Understanding the conformational motions of RCK gating rings.The Journal of general physiology · 2017Review
- Calcium ions open a selectivity filter gate during activation of the MthK potassium channel.Nature communications · 2015Article
- Initial steps of inactivation at the K+ channel selectivity filter.Proceedings of the National Academy of Sciences of the United States of America · 2014Article
- The voltage-dependent gate in MthK potassium channels is located at the selectivity filter.Nature structural & molecular biology · 2013Article
- Crystal structure of a Ba(2+)-bound gating ring reveals elementary steps in RCK domain activation.Structure (London, England : 1993) · 2012Article
- Structure and function of multiple Ca2+-binding sites in a K+ channel regulator of K+ conductance (RCK) domain.Proceedings of the National Academy of Sciences of the United States of America · 2011Article
- Voltage-dependent inactivation gating at the selectivity filter of the MthK K+ channel.The Journal of general physiology · 2010Article
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3 authors.
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Abstract
MthK is a Ca(2+)-gated K(+) channel whose activity is inhibited by cytoplasmic H(+). To determine possible mechanisms underlying the channel's proton sensitivity and the relation between H(+) inhibition and Ca(2+)-dependent gating, we recorded current through MthK channels incorporated into planar lipid bilayers. Each bilayer recording was obtained at up to six different [Ca(2+)] (ranging from nominally 0 to 30 mM) at a given [H(+)], in which the solutions bathing the cytoplasmic side of the channels were changed via a perfusion system to ensure complete solution exchanges. We observed a steep relation between [Ca(2+)] and open probability (Po), with a mean Hill coefficient (n(H)) of 9.9 +/- 0.9. Neither the maximal Po (0.93 +/- 0.005) nor n(H) changed significantly as a function of [H(+)] over pH ranging from 6.5 to 9.0. In addition, MthK channel activation in the nominal absence of Ca(2+) was not H(+) sensitive over pH ranging from 7.3 to 9.0. However, increasing [H(+)] raised the EC(50) for Ca(2+) activation by approximately 4.7-fold per tenfold increase in [H(+)], displaying a linear relation between log(EC(50)) and log([H(+)]) (i.e., pH) over pH ranging from 6.5 to 9.0. Collectively, these results suggest that H(+) binding does not directly modulate either the channel's closed-open equilibrium or the allosteric coupling between Ca(2+) binding and channel opening. We can account for the Ca(2+) activation and proton sensitivity of MthK gating quantitatively by assuming that Ca(2+) allosterically activates MthK, whereas H(+) opposes activation by destabilizing the binding of Ca(2+).
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