Journal article
Mechanism of calcium gating in small-conductance calcium-activated potassium channels
Nature (London), Vol.395(6701), pp.503-507
10/01/1998
Handle:
https://hdl.handle.net/2376/103465
PMID: 9774106
Abstract
The slow afterhyperpolarization that follows an action potential is generated by the activation of small-conductance calcium-activated potassium channels (SK channels). The slow afterhyperpolarization limits the firing frequency of repetitive action potentials (spike-frequency adaption) and is essential for normal neurotransmission. SK channels are voltage-independent and activated by submicromolar concentrations of intracellular calcium. They are high-affinity calcium sensors that transduce fluctuations in intracellular calcium concentrations into changes in membrane potential. Here we study the mechanism of calcium gating and find that SK channels are not gated by calcium binding directly to the channel α-subunits. Instead, the functional SK channels are heteromeric complexes with calmodulin, which is constitutively associated with the α-subunits in a calcium-independent manner. Our data support a model in which calcium gating of SK channels is mediated by binding of calcium to calmodulin and subsequent conformational alterations in the channel protein.
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Details
- Title
- Mechanism of calcium gating in small-conductance calcium-activated potassium channels
- Creators
- B Hirschberg - Vollum Institute, Oregon Health Sciences UniversityC. T Bond - Vollum Institute, Oregon Health Sciences UniversityX.-M Xia - Vollum Institute, Oregon Health Sciences UniversityA Rivard - Vollum Institute, Oregon Health Sciences UniversityJ. P Adelman - Vollum Institute, Oregon Health Sciences UniversityJ. E Keen - Vollum Institute, Oregon Health Sciences UniversityS Lutsenko - Biochemsitry and Molecular Biology, Oregon Health Sciences UniversityB Fakler - Department of Physiology, University of TuebingenJ Maylie - Obstetrics and Gynecology, Oregon Health Sciences UniversityT Johnson-Pais - Vollum Institute, Oregon Health Sciences UniversityT Ishii - Vollum Institute, Oregon Health Sciences UniversityG Wayman - Vollum Institute, Oregon Health Sciences University
- Publication Details
- Nature (London), Vol.395(6701), pp.503-507
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Identifiers
- 99900546543701842
- Language
- English
- Resource Type
- Journal article