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| | ==Crystal Structure of Ca2+/CaM:Kv7.4 (KCNQ4) B helix complex== | | ==Crystal Structure of Ca2+/CaM:Kv7.4 (KCNQ4) B helix complex== |
| - | <StructureSection load='4gow' size='340' side='right' caption='[[4gow]], [[Resolution|resolution]] 2.60Å' scene=''> | + | <StructureSection load='4gow' size='340' side='right'caption='[[4gow]], [[Resolution|resolution]] 2.60Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4gow]] is a 2 chain structure with sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4GOW OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4GOW FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4gow]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4GOW OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4GOW FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene></td></tr> | + | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.6Å</td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CALM1, CALM, CAM, CAM1, CALM2, CAM2, CAMB, CALM3, CALML2, CAM3, CAMC, CAMIII ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens]), KCNQ4 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=9606 Homo sapiens])</td></tr> | + | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</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=4gow FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4gow OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4gow RCSB], [http://www.ebi.ac.uk/pdbsum/4gow PDBsum]</span></td></tr> | + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4gow FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4gow OCA], [https://pdbe.org/4gow PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4gow RCSB], [https://www.ebi.ac.uk/pdbsum/4gow PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4gow ProSAT]</span></td></tr> |
| | </table> | | </table> |
| | == Disease == | | == Disease == |
| - | [[http://www.uniprot.org/uniprot/KCNQ4_HUMAN KCNQ4_HUMAN]] Defects in KCNQ4 are the cause of deafness autosomal dominant type 2A (DFNA2A) [MIM:[http://omim.org/entry/600101 600101]]. DFNA2A is a form of sensorineural hearing loss. Sensorineural deafness results from damage to the neural receptors of the inner ear, the nerve pathways to the brain, or the area of the brain that receives sound information.<ref>PMID:10025409</ref> <ref>PMID:10369879</ref> <ref>PMID:10571947</ref> <ref>PMID:10925378</ref> <ref>PMID:21242547</ref> | + | [https://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 == | | == Function == |
| - | [[http://www.uniprot.org/uniprot/KCNQ4_HUMAN KCNQ4_HUMAN]] Probably important in the regulation of neuronal excitability. May underlie a potassium current involved in regulating the excitability of sensory cells of the cochlea. KCNQ4 channels are blocked by linopirdin, XE991 and bepridil, whereas clofilium is without significant effect. Muscarinic agonist oxotremorine-M strongly suppress KCNQ4 current in CHO cells in which cloned KCNQ4 channels were coexpressed with M1 muscarinic receptors.<ref>PMID:11245603</ref> | + | [https://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 ==
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| - | Calmodulin (CaM) is an important regulator of Kv7.x (KCNQx) voltage-gated potassium channels. Channels from this family produce neuronal M currents and cardiac and auditory I(KS) currents and harbor mutations that cause arrhythmias, epilepsy, and deafness. Despite extensive functional characterization, biochemical and structural details of the interaction between CaM and the channel have remained elusive. Here, we show that both apo-CaM and Ca(2+)/CaM bind to the C-terminal tail of the neuronal channel Kv7.4 (KCNQ4), which is involved in both hearing and mechanosensation. Interactions between apo-CaM and the Kv7.4 tail involve two C-terminal tail segments, known as the A and B segments, whereas the interaction between Ca(2+)/CaM and the Kv7.4 C-terminal tail requires only the B segment. Biochemical studies show that the calcium dependence of the CaM:B segment interaction is conserved in all Kv7 subtypes. X-ray crystallographic determination of the structure of the Ca(2+)/CaM:Kv7.4 B segment complex shows that Ca(2+)/CaM wraps around the Kv7.4 B segment, which forms an alpha-helix, in an antiparallel orientation that embodies a variation of the classic 1-14 Ca(2+)/CaM interaction motif. Taken together with the context of prior studies, our data suggest a model for modulation of neuronal Kv7 channels involving a calcium-dependent conformational switch from an apo-CaM form that bridges the A and B segments to a Ca(2+)/CaM form bound to the B-helix. The structure presented here also provides a context for a number of disease-causing mutations and for further dissection of the mechanisms by which CaM controls Kv7 function.
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| - | Structure of a Ca(2+)/CaM:Kv7.4 (KCNQ4) B-Helix Complex Provides Insight into M Current Modulation.,Xu Q, Chang A, Tolia A, Minor DL Jr J Mol Biol. 2012 Nov 23. pii: S0022-2836(12)00895-9. doi:, 10.1016/j.jmb.2012.11.023. PMID:23178170<ref>PMID:23178170</ref>
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| - | From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br>
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| - | </div> | + | |
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| | ==See Also== | | ==See Also== |
| - | *[[Calmodulin|Calmodulin]] | + | *[[Calmodulin 3D structures|Calmodulin 3D structures]] |
| - | *[[Galactosidase|Galactosidase]]
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| | == References == | | == References == |
| | <references/> | | <references/> |
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| | </StructureSection> | | </StructureSection> |
| | [[Category: Homo sapiens]] | | [[Category: Homo sapiens]] |
| - | [[Category: Chang, A]] | + | [[Category: Large Structures]] |
| - | [[Category: Minor, D L]] | + | [[Category: Chang A]] |
| - | [[Category: Tolia, A]]
| + | [[Category: Minor Jr DL]] |
| - | [[Category: Xu, Q]] | + | [[Category: Tolia A]] |
| - | [[Category: Calmodulin]] | + | [[Category: Xu Q]] |
| - | [[Category: Ion channel]] | + | |
| - | [[Category: Potassium channel]]
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| - | [[Category: Protein binding]]
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| - | [[Category: Protein complex]]
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| Structural highlights
Disease
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
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).[1] [2] [3] [4]
See Also
References
- ↑ Tsang WY, Spektor A, Luciano DJ, Indjeian VB, Chen Z, Salisbury JL, Sanchez I, Dynlacht BD. CP110 cooperates with two calcium-binding proteins to regulate cytokinesis and genome stability. Mol Biol Cell. 2006 Aug;17(8):3423-34. Epub 2006 Jun 7. PMID:16760425 doi:10.1091/mbc.E06-04-0371
- ↑ Reichow SL, Clemens DM, Freites JA, Nemeth-Cahalan KL, Heyden M, Tobias DJ, Hall JE, Gonen T. Allosteric mechanism of water-channel gating by Ca-calmodulin. Nat Struct Mol Biol. 2013 Jul 28. doi: 10.1038/nsmb.2630. PMID:23893133 doi:10.1038/nsmb.2630
- ↑ Boczek NJ, Gomez-Hurtado N, Ye D, Calvert ML, Tester DJ, Kryshtal D, Hwang HS, Johnson CN, Chazin WJ, Loporcaro CG, Shah M, Papez AL, Lau YR, Kanter R, Knollmann BC, Ackerman MJ. Spectrum and Prevalence of CALM1-, CALM2-, and CALM3-Encoded Calmodulin Variants in Long QT Syndrome and Functional Characterization of a Novel Long QT Syndrome-Associated Calmodulin Missense Variant, E141G. Circ Cardiovasc Genet. 2016 Apr;9(2):136-146. doi:, 10.1161/CIRCGENETICS.115.001323. Epub 2016 Mar 11. PMID:26969752 doi:http://dx.doi.org/10.1161/CIRCGENETICS.115.001323
- ↑ Yu CC, Ko JS, Ai T, Tsai WC, Chen Z, Rubart M, Vatta M, Everett TH 4th, George AL Jr, Chen PS. Arrhythmogenic calmodulin mutations impede activation of small-conductance calcium-activated potassium current. Heart Rhythm. 2016 Aug;13(8):1716-23. doi: 10.1016/j.hrthm.2016.05.009. Epub 2016, May 7. PMID:27165696 doi:http://dx.doi.org/10.1016/j.hrthm.2016.05.009
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