Letter | Published:

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

Nature volume 441, pages 9195 (04 May 2006) | Download Citation



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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  1. 1.

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

  2. 2.

    , & Dihydropyridines with potent hypotensive activity prepared by the Hantzsch reaction. J. Pharm. Pharmacol. 24, 917–918 (1972)

  3. 3.

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

  4. 4.

    , , , & Mutations in the α1 subunit of an L-type voltage-activated Ca2+ channel cause myotonia in Caenorhabditis elegans. EMBO J. 16, 6066–6076 (1997)

  5. 5.

    , , , & The L-type voltage-dependent Ca2+ channel EGL-19 controls body wall muscle function in Caenorhabditis elegans. J. Cell Biol. 159, 337–348 (2002)

  6. 6.

    , , & Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings. Adv. Drug Deliv. Rev. 46, 3–26 (2001)

  7. 7.

    , , & Small molecule developmental screens reveal the logic and timing of vertebrate development. Proc. Natl Acad. Sci. USA 97, 12965–12969 (2000)

  8. 8.

    & Caenorhabditis elegans morphogenesis: the role of the cytoskeleton in elongation of the embryo. Dev. Biol. 117, 156–173 (1986)

  9. 9.

    , , & mab-20 encodes Semaphorin-2a and is required to prevent ectopic cell contacts during epidermal morphogenesis in Caenorhabditis elegans. Development 127, 755–767 (2000)

  10. 10.

    , & Egg-laying defective mutants of the nematode Caenorhabditis elegans. Genetics 104, 619–647 (1983)

  11. 11.

    , , & Molecular determinants of drug binding and action on L-type calcium channels. Annu. Rev. Pharmacol. Toxicol. 37, 361–396 (1997)

  12. 12.

    , , , & The C. elegans T-type calcium channel CCA-1 boosts neuromuscular transmission. J. Exp. Biol. 208, 2191–2203 (2005)

  13. 13.

    & A calcium-channel homologue required for adaptation to dopamine and serotonin in Caenorhabditis elegans. Nature 375, 73–78 (1995)

  14. 14.

    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)

  15. 15.

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

  16. 16.

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

  17. 17.

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

  18. 18.

    & Post-embryonic cell lineages of the nematode, Caenorhabditis elegans. Dev. Biol. 56, 110–156 (1977)

  19. 19.

    , , & The structure of the ventral nerve cord of Caenorhabditis elegans. Phil. Trans. R. Soc. Lond. B 275, 327–348 (1976)

  20. 20.

    , , & The structure of the nervous system of the nematode C. elegans. Phil. Trans. R. Soc. Lond. B 314, 1–340 (1986)

  21. 21.

    , , & Control of alternative behavioural states by serotonin in Caenorhabditis elegans. Neuron 21, 203–214 (1998)

  22. 22.

    , & Serotonin and Go modulate functional states of neurons and muscles controlling C. elegans egg-laying behaviour. Curr. Biol. 13, 1910–1915 (2003)

  23. 23.

    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)

  24. 24.

    , & Genes affecting sensitivity to serotonin in Caenorhabditis elegans. Genetics 143, 1219–1230 (1996)

  25. 25.

    , , , & Serotonin (5HT), fluoxetine, imipramine and dopamine target distinct 5HT receptor signaling to modulate Caenorhabditis elegans egg-laying behaviour. Genetics 169, 1425–1436 (2005)

  26. 26.

    , , & 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)

  27. 27.

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

  28. 28.

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

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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.

Author information

Author notes

    • Trevor C. Y. Kwok
    •  & Nicole Ricker

    *These authors contributed equally to this work


  1. Department of Medical Genetics and Microbiology, and The Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, 160 College Street, Toronto, Ontario M5S 3E1, Canada

    • Trevor C. Y. Kwok
    • , Nicole Ricker
    • , Andrew Burns
    •  & Peter J. Roy
  2. Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario M5S 3B2, Canada

    • Regina Fraser
    • , Peter McCourt
    •  & Sean R. Cutler
  3. Collaborative Program in Developmental Biology, University of Toronto, 25 Harbord Street, Toronto, Ontario M5S 3G5, Canada

    • Peter McCourt
    •  & Peter J. Roy
  4. Department of Physiology and Toronto Western Research Institute, University of Toronto, 399 Bathurst Street, Toronto, Ontario M5T 2S8, Canada

    • Allen W. Chan
    •  & Elise F. Stanley


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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.

Corresponding author

Correspondence to Peter J. Roy.

Supplementary information

PDF files

  1. 1.

    Supplementary Table 1

    The 308 bioactive molecules we identified in a small molecule screen.

  2. 2.

    Supplementary Table 2

    The structures of the 308 bioactive molecules we identified in a small molecule screen.

  3. 3.

    Supplementary Figures

    This file contains Supplementary Figures 1–4.

Word documents

  1. 1.

    Supplementary Notes

    This file contains Supplementary Methods, Supplementary Figure Legends and additional references.

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