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A small-molecule screen in C. elegans yields a new calcium channel antagonist


Small-molecule inhibitors of protein function are powerful tools for biological analysis1 and can lead to the development of new drugs. However, a major bottleneck in generating useful small-molecule tools is target identification. Here we show that Caenorhabditis elegans can provide a platform for both the discovery of new bioactive compounds and target identification. We screened 14,100 small molecules for bioactivity in wild-type worms and identified 308 compounds that induce a variety of phenotypes. One compound that we named nemadipine-A induces marked defects in morphology and egg-laying. Nemadipine-A resembles a class of widely prescribed anti-hypertension drugs called the 1,4-dihydropyridines (DHPs) that antagonize the α1-subunit of L-type calcium channels2,3. Through a genetic suppressor screen, we identified egl-19 as the sole candidate target of nemadipine-A, a conclusion that is supported by several additional lines of evidence. egl-19 encodes the only L-type calcium channel α1-subunit in the C. elegans genome4,5. We show that nemadipine-A can also antagonize vertebrate L-type calcium channels, demonstrating that worms and vertebrates share the orthologous protein target. Conversely, FDA-approved DHPs fail to elicit robust phenotypes, making nemadipine-A a unique tool to screen for genetic interactions with this important class of drugs. Finally, we demonstrate the utility of nemadipine-A by using it to reveal redundancy among three calcium channels in the egg-laying circuit. Our study demonstrates that C. elegans enables rapid identification of new small-molecule tools and their targets.

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Figure 1: The molecular structures of nemadipine-A, nemadipine-B, felodipine, and the core 1,4-dihydropyridine (DHP) structure.
Figure 2: Embryos raised on nemadipine hatch with Vab defects.
Figure 3: Animals grown on the nemadipines are Egl.
Figure 4: EGL-19 functions redundantly with both UNC-2 and CCA-1.


  1. Mayer, T. U. et al. Small molecule inhibitor of mitotic spindle bipolarity identified in a phenotype-based screen. Science 286, 971–974 (1999)

    Article  CAS  PubMed  Google Scholar 

  2. Loev, B., Ehrreich, S. J. & Tedeschi, R. E. Dihydropyridines with potent hypotensive activity prepared by the Hantzsch reaction. J. Pharm. Pharmacol. 24, 917–918 (1972)

    Article  CAS  PubMed  Google Scholar 

  3. Harrold, M. in Foye's Principles of Medicinal Chemistry (eds Williams, D. A. & Lemke, T. L.) 533–561 (Lippincott Williams and Wilkins, Baltimore, 2002)

    Google Scholar 

  4. Lee, R. Y., Lobel, L., Hengartner, M., Horvitz, H. R. & Avery, L. Mutations in the α1 subunit of an L-type voltage-activated Ca2+ channel cause myotonia in Caenorhabditis elegans. EMBO J. 16, 6066–6076 (1997)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Jospin, M., Jacquemond, V., Mariol, M. C., Segalat, L. & Allard, B. The L-type voltage-dependent Ca2+ channel EGL-19 controls body wall muscle function in Caenorhabditis elegans. J. Cell Biol. 159, 337–348 (2002)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Lipinski, C. A., Lombardo, F., Dominy, B. W. & Feeney, P. J. Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings. Adv. Drug Deliv. Rev. 46, 3–26 (2001)

    Article  CAS  PubMed  Google Scholar 

  7. Peterson, R. T., Link, B. A., Dowling, J. E. & Schreiber, S. L. Small molecule developmental screens reveal the logic and timing of vertebrate development. Proc. Natl Acad. Sci. USA 97, 12965–12969 (2000)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  8. Priess, J. R. & Hirsh, D. I. Caenorhabditis elegans morphogenesis: the role of the cytoskeleton in elongation of the embryo. Dev. Biol. 117, 156–173 (1986)

    Article  CAS  PubMed  Google Scholar 

  9. Roy, P. J., Zheng, H., Warren, C. E. & Culotti, J. G. mab-20 encodes Semaphorin-2a and is required to prevent ectopic cell contacts during epidermal morphogenesis in Caenorhabditis elegans. Development 127, 755–767 (2000)

    CAS  PubMed  Google Scholar 

  10. Trent, C., Tsuing, N. & Horvitz, H. R. Egg-laying defective mutants of the nematode Caenorhabditis elegans. Genetics 104, 619–647 (1983)

    CAS  PubMed  PubMed Central  Google Scholar 

  11. Hockerman, G. H., Peterson, B. Z., Johnson, B. D. & Catterall, W. A. Molecular determinants of drug binding and action on L-type calcium channels. Annu. Rev. Pharmacol. Toxicol. 37, 361–396 (1997)

    Article  CAS  PubMed  Google Scholar 

  12. Steger, K. A., Shtonda, B. B., Thacker, C., Snutch, T. P. & Avery, L. The C. elegans T-type calcium channel CCA-1 boosts neuromuscular transmission. J. Exp. Biol. 208, 2191–2203 (2005)

    Article  CAS  PubMed  Google Scholar 

  13. Schafer, W. R. & Kenyon, C. J. A calcium-channel homologue required for adaptation to dopamine and serotonin in Caenorhabditis elegans. Nature 375, 73–78 (1995)

    Article  ADS  CAS  PubMed  Google Scholar 

  14. Franks, C. J. et al. Ionic basis of the resting membrane potential and action potential in the pharyngeal muscle of Caenorhabditis elegans. J. Neurophysiol. 87, 954–961 (2002)

    Article  CAS  PubMed  Google Scholar 

  15. Shtonda, B. & Avery, L. CCA-1, EGL-19 and EXP-2 currents shape action potentials in the Caenorhabditis elegans pharynx. J. Exp. Biol. 208, 2177–2190 (2005)

    Article  CAS  PubMed  Google Scholar 

  16. Stanley, E. F. & Atrakchi, A. H. Calcium currents recorded from a vertebrate presynaptic nerve terminal are resistant to the dihydropyridine nifedipine. Proc. Natl Acad. Sci. USA 87, 9683–9687 (1990)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  17. Furukawa, T. et al. Selectivities of dihydropyridine derivatives in blocking Ca2+ channel subtypes expressed in Xenopus oocytes. J. Pharmacol. Exp. Ther. 291, 464–473 (1999)

    CAS  PubMed  Google Scholar 

  18. Sulston, J. E. & Horvitz, H. R. Post-embryonic cell lineages of the nematode, Caenorhabditis elegans. Dev. Biol. 56, 110–156 (1977)

    Article  CAS  PubMed  Google Scholar 

  19. White, J. G., Southgate, E., Thomson, J. N. & Brenner, S. The structure of the ventral nerve cord of Caenorhabditis elegans. Phil. Trans. R. Soc. Lond. B 275, 327–348 (1976)

    Article  ADS  CAS  Google Scholar 

  20. White, J. G., Southgate, E., Thomson, J. N. & Brenner, S. The structure of the nervous system of the nematode C. elegans. Phil. Trans. R. Soc. Lond. B 314, 1–340 (1986)

    Article  ADS  CAS  Google Scholar 

  21. Waggoner, L. E., Zhou, G. T., Schafer, R. W. & Schafer, W. R. Control of alternative behavioural states by serotonin in Caenorhabditis elegans. Neuron 21, 203–214 (1998)

    Article  CAS  PubMed  Google Scholar 

  22. Shyn, S. I., Kerr, R. & Schafer, W. R. Serotonin and Go modulate functional states of neurons and muscles controlling C. elegans egg-laying behaviour. Curr. Biol. 13, 1910–1915 (2003)

    Article  CAS  PubMed  Google Scholar 

  23. Mathews, E. A. et al. Critical residues of the Caenorhabditis elegans unc-2 voltage-gated calcium channel that affect behavioural and physiological properties. J. Neurosci. 23, 6537–6545 (2003)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Schafer, W. R., Sanchez, B. M. & Kenyon, C. J. Genes affecting sensitivity to serotonin in Caenorhabditis elegans. Genetics 143, 1219–1230 (1996)

    CAS  PubMed  PubMed Central  Google Scholar 

  25. Dempsey, C. M., Mackenzie, S. M., Gargus, A., Blanco, G. & Sze, J. Y. Serotonin (5HT), fluoxetine, imipramine and dopamine target distinct 5HT receptor signaling to modulate Caenorhabditis elegans egg-laying behaviour. Genetics 169, 1425–1436 (2005)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Weinshenker, D., Wei, A., Salkoff, L. & Thomas, J. H. Block of an ether-a-go-go-like K+ channel by imipramine rescues egl-2 excitation defects in Caenorhabditis elegans. J. Neurosci. 19, 9831–9840 (1999)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Lewis, J. A. & Fleming, J. T. in Caenorhabditis elegans: Modern Biological Analysis of an Organism (eds Epstein, H. F. & Shakes, D. C.) (Academic, San Diego, 1995)

    Google Scholar 

  28. Brenner, S. The genetics of Caenorhabditis elegans. Genetics 77, 71–94 (1974)

    CAS  PubMed  PubMed Central  Google Scholar 

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We thank J. Turnbull, S. Ito and H. Cheung for technical assistance, S. Dixon, C. Boone and B. Andrews for advice on the manuscript, and A. Spence for sharing equipment. We thank the C. elegans Genetic Center, which is funded by the NIH National Center for Research Resources, for sending us worm strains. E.F.S., P.M., S.R.C. and P.J.R. are Canadian Research Chairs in brain and behaviour, plant molecular biology, plant genomics, and molecular neurobiology, respectively. This work was supported by an NSERC Industrial Grant to P.M., a CIHR Grant to E.F.S., a CIHR CGS to A.W.C., and a Premier's Research Excellence Award and awards from the Canadian Foundation for Innovation and Ontario Innovation Trust to P.J.R. Author Contributions R.F. discovered that nemadipine-A induces the Vab phenotype, T.C.Y.K. and P.J.R. did the worm genetics and pharmacological analysis, P.M., R.F., A.B. and P.J.R. did the small-molecule screen, A.W.C. and E.F.S. did the electrophysiology, and S.R.C. did the HPLC analysis. N.R. provided technical assistance throughout. With critical input from S.R.C., P.J.R. led the project and wrote the paper.

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Correspondence to Peter J. Roy.

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Competing interests

P.J.R. owns shares in, and is Science Advisor to, a company (Elegenics Inc.) that built a robot named/described in this paper.

Supplementary information

Supplementary Table 1

The 308 bioactive molecules we identified in a small molecule screen. (PDF 40 kb)

Supplementary Table 2

The structures of the 308 bioactive molecules we identified in a small molecule screen. (PDF 213 kb)

Supplementary Figures

This file contains Supplementary Figures 1–4. (PDF 958 kb)

Supplementary Notes

This file contains Supplementary Methods, Supplementary Figure Legends and additional references. (DOC 56 kb)

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Kwok, T., Ricker, N., Fraser, R. et al. A small-molecule screen in C. elegans yields a new calcium channel antagonist. Nature 441, 91–95 (2006).

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