ArticleProceedings of the National Academy of Sciences of the United States of America2002
Stepwise contribution of each subunit to the cooperative activation of BK channels by Ca2+.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2002. The graph could read no effect estimate from its abstract, so it casts no vote on the map. An erratum has been issued. Cited by 44 papers.
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Who cites it
44 citing papers in PubMed.
- Effects of emodepside on single-channel properties of Onchocerca volvulus SLO-1A (BK) potassium channels.Parasites & vectors · 2025Article
- PIP2-driven cytoplasmic domain motions are coupled to Kir2 channel gating.The Journal of general physiology · 2025Article
- Redox Regulation of KAntioxidants & redox signaling · 2024Review
- Cooperative Gating of a KJournal of the American Chemical Society · 2024Article
- Identifiability of equilibrium constants for receptors with two to five binding sites.The Journal of general physiology · 2023Article
- BK channels of five different subunit combinations underlie the de novo KCNMA1 G375R channelopathy.The Journal of general physiology · 2023Article
- Derepression may masquerade as activation in ligand-gated ion channels.Nature communications · 2023Article
- The allosteric gating mechanism of the MthK channel.National science review · 2022Article
- Ancestral acetylcholine receptor β-subunit forms homopentamers that prime before opening spontaneously.eLife · 2022Article
- State-dependent inhibition of BK channels by the opioid agonist loperamide.The Journal of general physiology · 2021Article
- A single historical substitution drives an increase in acetylcholine receptor complexity.Proceedings of the National Academy of Sciences of the United States of America · 2021Article
- A Calcium Sensor Discovered in Bluetongue Virus Nonstructural Protein 2 Is Critical for Virus Replication.Journal of virology · 2020Article
- Molecular mechanism of BK channel activation by the smooth muscle relaxant NS11021.The Journal of general physiology · 2020Article
- Article
- Structural basis for gating the high-conductance CaNature · 2017Article
- A New Splice Variant of Large Conductance Ca2+-activated K+ (BK) Channel α Subunit Alters Human Chondrocyte Function.The Journal of biological chemistry · 2016Article
- Stoichiometry for α-bungarotoxin block of α7 acetylcholine receptors.Nature communications · 2015Article
- Cadmium-cysteine coordination in the BK inner pore region and its structural and functional implications.Proceedings of the National Academy of Sciences of the United States of America · 2015Article
- Single-channel kinetics of BK (Slo1) channels.Frontiers in physiology · 2014Review
- Free-energy relationships in ion channels activated by voltage and ligand.The Journal of general physiology · 2013Article
Corrections and comments
- Erratum issued
Authors and funding
2 authors.
Funding
Abstract
BK channels (Slo1) are widely distributed K+ channels that control Ca2+-dependent processes and cellular excitability. Their activation by intracellular Ca2+ (Ca(i)2+) is highly cooperative, with Hill coefficients of typically 2-5. To investigate the cooperativity contributed by each of the four alpha subunits that form the BK channel, we studied single channels comprised of mixtures of functional subunits and subunits with a mutation to disrupt a key site (Ca-bowl) required for activation by low concentrations of Ca(i)2+. As the number of functional subunits increased, we found a stepwise increase in the Hill coefficient of 0.3-0.8 per functional subunit and a stepwise decrease in the Ca(i)2+ required for half activation (K(d)). These results show directly that BK channels can open with 0, 1, 2, 3, or 4 functional Ca-bowls, and that each subunit with a functional Ca-bowl contributes a stepwise increase to both the cooperativity of activation and the apparent Ca2+ affinity. A model with 0-4 high-affinity allosteric activators and four low-affinity allosteric activators was examined. In this model, Ca2+ bindings were independent of one another and the cooperativity arose from the joint action of the allosteric activators on the open-closed equilibrium. Although this model described well the major features of the experimental data, some differences between the observed and predicted results indicated that additional factors not included in the model also contribute to the cooperativity.
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