| 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] [SCN4A_RAT] This protein mediates the voltage-dependent sodium ion permeability of excitable membranes. Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a sodium-selective channel through which Na(+) ions may pass in accordance with their electrochemical gradient. This sodium channel may be present in both denervated and innervated skeletal muscle.[5]
Publication Abstract from PubMed
Voltage-gated sodium (NaV) and calcium channels (CaV) form targets for calmodulin (CaM), which affects channel inactivation properties. A major interaction site for CaM resides in the C-terminal (CT) region, consisting of an IQ domain downstream of an EF-hand domain. We present a crystal structure of fully Ca(2+)-occupied CaM, bound to the CT of NaV1.5. The structure shows that the C-terminal lobe binds to a site approximately 90 degrees rotated relative to a previous site reported for an apoCaM complex with the NaV1.5 CT and for ternary complexes containing fibroblast growth factor homologous factors (FHF). We show that the binding of FHFs forces the EF-hand domain in a conformation that does not allow binding of the Ca(2+)-occupied C-lobe of CaM. These observations highlight the central role of the EF-hand domain in modulating the binding mode of CaM. The binding sites for Ca(2+)-free and Ca(2+)-occupied CaM contain targets for mutations linked to long-QT syndrome, a type of inherited arrhythmia. The related NaV1.4 channel has been shown to undergo Ca(2+)-dependent inactivation (CDI) akin to CaVs. We present a crystal structure of Ca(2+)/CaM bound to the NaV1.4 IQ domain, which shows a binding mode that would clash with the EF-hand domain. We postulate the relative reorientation of the EF-hand domain and the IQ domain as a possible conformational switch that underlies CDI.
Crystal structures of Ca(2+)-calmodulin bound to NaV C-terminal regions suggest role for EF-hand domain in binding and inactivation.,Gardill BR, Rivera-Acevedo RE, Tung CC, Van Petegem F Proc Natl Acad Sci U S A. 2019 May 9. pii: 1818618116. doi:, 10.1073/pnas.1818618116. PMID:31072926[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
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
- ↑ Trimmer JS, Cooperman SS, Tomiko SA, Zhou JY, Crean SM, Boyle MB, Kallen RG, Sheng ZH, Barchi RL, Sigworth FJ, et al.. Primary structure and functional expression of a mammalian skeletal muscle sodium channel. Neuron. 1989 Jul;3(1):33-49. PMID:2559760
- ↑ Gardill BR, Rivera-Acevedo RE, Tung CC, Van Petegem F. Crystal structures of Ca(2+)-calmodulin bound to NaV C-terminal regions suggest role for EF-hand domain in binding and inactivation. Proc Natl Acad Sci U S A. 2019 May 9. pii: 1818618116. doi:, 10.1073/pnas.1818618116. PMID:31072926 doi:http://dx.doi.org/10.1073/pnas.1818618116
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