Potassium Channel: Difference between revisions

<StructureSection load='' size='500' side='right' caption='Structure of the Potassium Channel, ([[2r9r]])' scene='Potassium_Channel/Opening/1'>

[[Image:2r9r Picture Proteopedia2.png|250px|left]]&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; [[Potassium Channel]]'''s''' control the electric potential across cell membranes by selectively catalyzing the diffusion of K⁺ ions down their electrochemical gradient.<ref name="Zhou">PMID: 11689936</ref> K⁺ Channels extend across the cell membrane, a 40Å thick lipid bilayer across which ions cannot pass without assistance.<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, to initiate cellular communication processes like neurotransmitter release or activate intercellular processes muscle contraction. At the onset of an action potential, sodium ions flood across the plasma membrane of neurons via sodium channels. This influx of sodium ions causes the polarity of the plasma membrane to reverse, inactivating sodium channels and activating potassium 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>