Potassium Channel: Difference between revisions

<StructureSection load='' size='400' side='right' caption='Structure of the Potassium Channel complex with K+ ions, ([[2r9r]])' scene='Potassium_Channel/Opening/1'>

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [[Potassium Channel]]'''s''' control cell membrane electric potentials by selectively allowing diffusion of K⁺ across the membrane.<ref name="Zhou">PMID: 11689936</ref> K⁺ Channels extend across the cell membrane, a 40Å thick lipid bilayer which ions cannot cross.<ref name="Doyle">PMID: 9525859</ref> Potassium homeostasis is crucial for nearly all living cells, but is particularly important for the correct function of neurons. Neurons produce electrical impulses known as action potentials, allow for cellular communication processes like neurotransmitter release or to initiate intercellular processes muscle contraction. At the onset of an action potential, sodium ions flood across the plasma membrane of neurons via sodium channels. The change in polarity of the plasma membrane caused by the sodium ion influx inactivates sodium channels. Potassium channels subsequently open allowing the selective diffusion of K⁺ ions across the plasma membrane, returning the membrane polarity to neutral. After the action potential has passed, channels recreate the high potassium concentration within the cell in preparation for the next stiumulus.<ref>PMID:12721618</ref> Mutations in voltage-gated potassium channel KCNC3 have been linked with [[Neurodevelopmental Disorders|neurodevelopmental disorders]] and neurodegeneration.<ref>PMID: 16501573</ref>