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Activation of calmodulin by various metal cations as a function of ionic radius.
Abstract
The active form of calmodulin is a Ca2+ . calmodulin complex. The purpose of this investigation was to determine whether other metal cations substitute for Ca2+ to activate calmodulin. Binding of Ca2+ resulted in an altered conformation of calmodulin with an increased quantum yield in its tyrosine fluorescence. Qualitatively similar results were obtained with Zn2+, Mn2+, Cd2+, Hg2+, Sr2+, Pb2+, Tb3+, Sm3+, and La3+. The relative extents of fluorescence enhancement by these cations were related to their ionic radii: all cations with ionic radii close to Ca2+ (0.99 A) increased tyrosine fluorescence, whereas those with different ionic radii were not effective, or much less so. The change in calmodulin conformation by the cations was confirmed by its altered electrophoretic mobility on polyacrylamide gels. Cations that change the conformation of calmodulin allow it to stimulate phosphodiesterase. The relative extents of stimulation of phosphodiesterase by cations were also related to their ionic radii. Finally, the ability of metal cations to inhibit Ca2+ binding was similarly related to their ionic radii. In general, the closer the radius of a metal cation was to that of Ca2+, the more effective was the cation to substitute for Ca2+. The range of effective ionic radii was approximately 1 +/- 0.2 A. Calmodulin-stimulated phosphodiesterase activity by the cations was reversed by trifluoperazine, an antagonist of calmodulin.
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Cited by
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Zhang, R., Khoo, M. S. C., Wu, Y., Yang, Y., Grueter, C. E., Ni, G., Price, E. E., Thiel, W., Guatimosim, S., Song, L.-S., et al. (2005) · Nature Medicine · doi:10.1038/nm1215 · Cited by 579
Calmodulin bifurcates the local Ca2+ signal that modulates P/Q-type Ca2+ channels
DeMaria, C. D., Soong, T. W., Alseikhan, B. A., Alvania, R. S., & Yue, D. T. (2001) · Nature · doi:10.1038/35078091 · Cited by 407
Inactivation of NMDA channels in cultured hippocampal neurons by intracellular calcium
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Unified Mechanisms of Ca2+ Regulation across the Ca2+ Channel Family
Liang, H., DeMaria, C. D., Erickson, M. G., Mori, M. X., Alseikhan, B. A., & Yue, D. T. (2003) · Neuron · doi:10.1016/s0896-6273(03)00560-9 · Cited by 305
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Sugita, S., Shin, O.-H., Han, W., Lao, Y., & Südhof, T. C. (2002) · The EMBO Journal · doi:10.1093/emboj/21.3.270 · Cited by 278
Metadata
- Authors
- Chao, S. H., Suzuki, Y., Zysk, J. R., & Cheung, W. Y.
- Venue
- Molecular Pharmacology
- Publisher
- Elsevier BV
- Published
- 1984-07
- Volume
- 26
- Issue
- 1
- Pages
- 75-82
- ISSN
- 0026-895X (ISSN-L)
- OpenAlex
- W1950452389
- Cited by
- 343
- References
- 0
- FWCI
- 5.60
- Type
- journal article
- Language
- en
- Open access
- closed
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- Chao, S. H., Suzuki, Y., Zysk, J. R., & Cheung, W. Y. (1984). Activation of calmodulin by various metal cations as a function of ionic radius. Molecular Pharmacology. https://doi.org/10.1016/s0026-895x(25)14991-2
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Contains information from the Semantic Scholar Academic Graph Datasets, made available under the ODC Attribution License (ODC-BY 1.0).
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