View source for 6b8q


==Crystal Structure of the Mg2+/CaM:Kv7.5 (KCNQ5) AB domain complex==
<StructureSection load='6b8q' size='340' side='right' caption='[[6b8q]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6b8q]] is a 8 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6B8Q OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6B8Q FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6b8q FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6b8q OCA], [http://pdbe.org/6b8q PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6b8q RCSB], [http://www.ebi.ac.uk/pdbsum/6b8q PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6b8q ProSAT]</span></td></tr>
</table>
== Disease ==
[[http://www.uniprot.org/uniprot/KCNQ5_HUMAN KCNQ5_HUMAN]] The disease is caused by mutations affecting the gene represented in this entry. [[http://www.uniprot.org/uniprot/CALM1_HUMAN CALM1_HUMAN]] The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of CPVT4.  The disease is caused by mutations affecting the gene represented in this entry. Mutations in CALM1 are the cause of LQT14. 
== Function ==
[[http://www.uniprot.org/uniprot/KCNQ5_HUMAN KCNQ5_HUMAN]] Associates with KCNQ3 to form a potassium channel which contributes to M-type current, a slowly activating and deactivating potassium conductance which plays a critical role in determining the subthreshold electrical excitability of neurons. Therefore, it is important in the regulation of neuronal excitability. May contribute, with other potassium channels, to the molecular diversity of a heterogeneous population of M-channels, varying in kinetic and pharmacological properties, which underlie this physiologically important current. Insensitive to tetraethylammonium, but inhibited by barium, linopirdine and XE991. Activated by niflumic acid and the anticonvulsant retigabine. As the native M-channel, the potassium channel composed of KCNQ3 and KCNQ5 is also suppressed by activation of the muscarinic acetylcholine receptor CHRM1.<ref>PMID:10787416</ref> <ref>PMID:11159685</ref> <ref>PMID:28669405</ref>  [[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>  
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Kv7 (KCNQ) voltage-gated potassium channels control excitability in the brain, heart, and ear. Calmodulin (CaM) is crucial for Kv7 function, but how this calcium sensor affects activity has remained unclear. Here, we present X-ray crystallographic analysis of CaM:Kv7.4 and CaM:Kv7.5 AB domain complexes that reveal an Apo/CaM clamp conformation and calcium binding preferences. These structures, combined with small-angle X-ray scattering, biochemical, and functional studies, establish a regulatory mechanism for Kv7 CaM modulation based on a common architecture in which a CaM C-lobe calcium-dependent switch releases a shared Apo/CaM clamp conformation. This C-lobe switch inhibits voltage-dependent activation of Kv7.4 and Kv7.5 but facilitates Kv7.1, demonstrating that mechanism is shared by Kv7 isoforms despite the different directions of CaM modulation. Our findings provide a unified framework for understanding how CaM controls different Kv7 isoforms and highlight the role of membrane proximal domains for controlling voltage-gated channel function. VIDEO ABSTRACT.

A Calmodulin C-Lobe Ca(2+)-Dependent Switch Governs Kv7 Channel Function.,Chang A, Abderemane-Ali F, Hura GL, Rossen ND, Gate RE, Minor DL Jr. Neuron. 2018 Feb 21;97(4):836-852.e6. doi: 10.1016/j.neuron.2018.01.035. Epub, 2018 Feb 8. PMID:29429937<ref>PMID:29429937</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6b8q" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Abderemane-Ali, F]]
[[Category: Chang, A]]
[[Category: Minor, D L]]
[[Category: Complex]]
[[Category: Ion channel]]
[[Category: Metal transport]]