Potassium channels

Potassium channels are the most widely distributed type of ion channel and have crucial roles in both excitable and non-excitable cells.  Potassium channels span cell membranes and control transportation of  potassium ions in and out of cells.  The basic organization of potassium channels is a tetramer with each monomer containing one pore-forming domain.  Four major classes of potassium channels exist - calcium-activated potassium channels, which open in response to calcium ions or other signalling molecules, inwardly rectifying potassium channels, which pass current more easily into the cell, tandem pore domain potassium channels, which are constitutively open or possess high basal activation, (the "resting potassium channels" or "leak channels")  and voltage-gated potassium channels, which open or close in response to the transmembrane voltage.   Potassium channels are found in most cell types and control a wide variety of functions including maintaining vascular tone.  Activation of potassium channels regulates excitability and can influence cognition, muscle contraction and hormone secretion. 

Further reading

Kuang et al (2015) Structure of potassium channels. Cell Mol Life Sci. 72(19) 3677 PMID: 26070303

Grandi et al (2017), Potassium channels in the heart: structure, function and regulation. J Physiol 595 2209 PMID: 27861921

Alexander et al (2019) The Concise Guide to PHARMACOLOGY 2019/20: Ion channels. Br J Pharmacol. 176 Issue S1 S142 PMID: 31710715

Tan et al (2025) Structural basis of fast N-type inactivation in Kv channels. Nature  https://doi.org/10.1038/s41586-025-09339-7