| Summary: | Bacterial potassium channels shut (left, PDB 1k4c) and open (right, 1Inq). They can sense voltage differences across membrane, and then change conformation. In the field of cell biology, potassium channels are the most widely distributed type of ion channel and are found in virtually all living organisms. They form potassium-selective pores that span cell membranes. Furthermore, potassium channels are found in most cell types and control a wide variety of cell functions. In excitable cells such as neurons, they shape action potentials and set the resting membrane potential. By contributing to the regulation of the action potential duration in cardiac muscle, malfunction of potassium channels may cause life-threatening arrhythmias. They also regulate cellular processes such as the secretion of hormones (e.g., insulin release from beta-cells in the pancreas) so their malfunction can lead to diseases (such as diabetes).
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