Potassium Channels


Potassium channels constitute a highly diverse class of ion channel and thus participate in multiple modulatory functions. There are several functional types of K+ channel, including voltage‐gated K+ channels, Ca2+‐activated K+ channels, inward rectifiers, leak K+ channels and Na+‐activated K+ channels. Principal or pore‐forming subunits of at least the first four types have been identified and are classified into three groups of proteins on the basis of their structural properties.

Keywords: potassium channels; ion channels; electrophysiology; membrane proteins; transport proteins

Figure 1.

Functional K+ channels in mammalian cells can be divided into those that are activated by Ca2+ (Ca2+‐activated K+ channels) or membrane voltage (voltage‐activated K+ channels). The K+ channels not gated by voltage either exhibit the property of inward rectification (inward rectifier K+ channels) or behave as simple K+‐permeable ‘holes’ in the membrane (‘leak’ K+ channels). Na+‐activated K+ channels are not shown here.

Figure 2.

Classification of K+ channel principal subunits into those having two, four or six transmembrane domains (TMDs) in a continuous polypeptide. Transmembrane segments are shown as cylinders spanning the membrane (the intra‐ and extracellular side is indicated). The schematic views from the top illustrate the dimeric (in the case of four‐TMD channels) or tetrameric (in the case of two‐TMD or six‐TMD channels structure). The darker shading represents one of the principal subunits in the channel complex.



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Further Reading

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Web Links

Molecular Diversity of K+ Channels http://k‐channels.med.nyu.edu/

Mammalian 2P domain and background K+ channels (K2P) http://www.ipmc.cnrs.fr/∼duprat/2p/index.htm

Permeation of Ions Across the Potassium Channel http://anusf.anu.edu.au/Vizlab/viz_showcase/shinho_chung/

Ion Channels, Transmitters, Receptors and Disease http://www.neuro.wustl.edu/neuromuscular/mother/chan.html

Neurotoxins http://faculty.washington.edu/chudler/toxin1.html

Ion Channel Slides http://www.sigma‐aldrich.com/saws.nsf/Pages/sg_ls_cs_ionchannelslide_home

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Coetzee, William A, and Rudy, Bernardo(Jan 2006) Potassium Channels. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0005670]