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== Function ==
== Function ==
[[http://www.uniprot.org/uniprot/KCNQ1_HUMAN KCNQ1_HUMAN]] Probably important in cardiac repolarization. Associates with KCNE1 (MinK) to form the I(Ks) cardiac potassium current. Elicits a rapidly activating, potassium-selective outward current. Muscarinic agonist oxotremorine-M strongly suppresses KCNQ1/KCNE1 current in CHO cells in which cloned KCNQ1/KCNE1 channels were coexpressed with M1 muscarinic receptors. May associate also with KCNE3 (MiRP2) to form the potassium channel that is important for cyclic AMP-stimulated intestinal secretion of chloride ions, which is reduced in cystic fibrosis and pathologically stimulated in cholera and other forms of secretory diarrhea. [[http://www.uniprot.org/uniprot/CALM1_HUMAN CALM1_HUMAN]] Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding. Among the enzymes to be stimulated by the calmodulin-calcium complex are a number of protein kinases and phosphatases. Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis (PubMed:16760425). Mediates calcium-dependent inactivation of CACNA1C (PubMed:26969752). Positively regulates calcium-activated potassium channel activity of KCNN2 (PubMed:27165696).<ref>PMID:16760425</ref> <ref>PMID:23893133</ref> <ref>PMID:26969752</ref> <ref>PMID:27165696</ref>
[[http://www.uniprot.org/uniprot/KCNQ1_HUMAN KCNQ1_HUMAN]] Probably important in cardiac repolarization. Associates with KCNE1 (MinK) to form the I(Ks) cardiac potassium current. Elicits a rapidly activating, potassium-selective outward current. Muscarinic agonist oxotremorine-M strongly suppresses KCNQ1/KCNE1 current in CHO cells in which cloned KCNQ1/KCNE1 channels were coexpressed with M1 muscarinic receptors. May associate also with KCNE3 (MiRP2) to form the potassium channel that is important for cyclic AMP-stimulated intestinal secretion of chloride ions, which is reduced in cystic fibrosis and pathologically stimulated in cholera and other forms of secretory diarrhea. [[http://www.uniprot.org/uniprot/CALM1_HUMAN CALM1_HUMAN]] Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding. Among the enzymes to be stimulated by the calmodulin-calcium complex are a number of protein kinases and phosphatases. Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis (PubMed:16760425). Mediates calcium-dependent inactivation of CACNA1C (PubMed:26969752). Positively regulates calcium-activated potassium channel activity of KCNN2 (PubMed:27165696).<ref>PMID:16760425</ref> <ref>PMID:23893133</ref> <ref>PMID:26969752</ref> <ref>PMID:27165696</ref>
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== Publication Abstract from PubMed ==
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KCNQ1, also known as Kv7.1, is a voltage-dependent K(+) channel that regulates gastric acid secretion, salt and glucose homeostasis, and heart rhythm. Its functional properties are regulated in a tissue-specific manner through co-assembly with beta subunits KCNE1-5. In non-excitable cells, KCNQ1 forms a complex with KCNE3, which suppresses channel closure at negative membrane voltages that otherwise would close it. Pore opening is regulated by the signaling lipid PIP2. Using cryoelectron microscopy (cryo-EM), we show that KCNE3 tucks its single-membrane-spanning helix against KCNQ1, at a location that appears to lock the voltage sensor in its depolarized conformation. Without PIP2, the pore remains closed. Upon addition, PIP2 occupies a site on KCNQ1 within the inner membrane leaflet, which triggers a large conformational change that leads to dilation of the pore's gate. It is likely that this mechanism of PIP2 activation is conserved among Kv7 channels.
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Structural Basis of Human KCNQ1 Modulation and Gating.,Sun J, MacKinnon R Cell. 2020 Jan 23;180(2):340-347.e9. doi: 10.1016/j.cell.2019.12.003. Epub 2019, Dec 26. PMID:31883792<ref>PMID:31883792</ref>
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From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6uzz" style="background-color:#fffaf0;"></div>
== References ==
== References ==
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<references/>

Revision as of 09:10, 5 February 2020

structure of human KCNQ1-CaM complex

PDB ID 6uzz

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