Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Structural plasticity and dynamic selectivity of acid-sensing ion channel–spider toxin complexes

Abstract

Acid-sensing ion channels (ASICs) are voltage-independent, amiloride-sensitive channels involved in diverse physiological processes ranging from nociception to taste. Despite the importance of ASICs in physiology, we know little about the mechanism of channel activation. Here we show that psalmotoxin activates non-selective and Na+-selective currents in chicken ASIC1a at pH 7.25 and 5.5, respectively. Crystal structures of ASIC1a–psalmotoxin complexes map the toxin binding site to the extracellular domain and show how toxin binding triggers an expansion of the extracellular vestibule and stabilization of the open channel pore. At pH 7.25 the pore is approximately 10 Å in diameter, whereas at pH 5.5 the pore is largely hydrophobic and elliptical in cross-section with dimensions of approximately 5 by 7 Å, consistent with a barrier mechanism for ion selectivity. These studies define mechanisms for activation of ASICs, illuminate the basis for dynamic ion selectivity and provide the blueprints for new therapeutic agents.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Prices may be subject to local taxes which are calculated during checkout

Figure 1: PcTx1 activates the chicken ASIC1a Δ13 construct.
Figure 2: Extensive interactions adhere PcTx1 to the Δ13 ion channel.
Figure 3: Conformational changes in the extracellular domain.
Figure 4: Structural rearrangements and ion selectivity of the transmembrane pores.
Figure 5: Cs + binding sites.
Figure 6: Schematic representation of gating.

Similar content being viewed by others

Accession codes

Primary accessions

Protein Data Bank

Data deposits

Structures for low-pH and high-pH D13–PcTx1 complexes have been deposited in PDB under accession numbers 4FZ0 and 4FZ1, respectively.

References

  1. Gründer, S. & Chen, X. Structure, function, and pharmacology of acid-sensing ion channels (ASICs): focus on ASIC1a. Int. J. Physiol. Pathophysiol. Pharmacol. 2, 73–94 (2010)

    PubMed  PubMed Central  Google Scholar 

  2. Kellenberger, S. & Schild, L. Epithelial sodium channel/degenerin family of ion channels: a variety of functions for a shared structure. Physiol. Rev. 82, 735–767 (2002)

    Article  CAS  Google Scholar 

  3. Kashlan, O. B. & Kleyman, T. R. ENaC structure and function in the wake of a resolved structure of a family member. Am. J. Physiol. Renal Physiol. 301, F684–F696 (2011)

    Article  CAS  Google Scholar 

  4. Krishtal, O. A. & Pidoplichko, V. I. A receptor for protons in the nerve cell membrane. Neuroscience 5, 2325–2327 (1980)

    Article  CAS  Google Scholar 

  5. Waldmann, R. Proton-gated cation channels–neuronal acid sensors in the central and peripheral nervous system. Adv. Exp. Med. Biol. 502, 293–304 (2001)

    Article  CAS  Google Scholar 

  6. Alvarez de la Rosa, D. et al. Distribution, subcellular localization and ontogeny of ASIC1 in the mammalian central nervous system. J. Physiol. (Lond.) 546, 77–87 (2003)

    Article  CAS  Google Scholar 

  7. Wemmie, J. A. et al. Acid-sensing ion channel 1 is localized in brain regions with high synaptic density and contributes to fear conditioning. J. Neurosci. 23, 5496–5502 (2003)

    Article  CAS  Google Scholar 

  8. Deval, E. et al. Acid-sensing ion channels (ASICs): pharmacology and implication in pain. Pharmacol. Ther. 128, 549–558 (2010)

    Article  CAS  Google Scholar 

  9. Bohlen, C. J. et al. A heteromeric Texas coral snake toxin targets acid-sensing ion channels to produce pain. Nature 479, 410–414 (2011)

    Article  CAS  ADS  Google Scholar 

  10. Coryell, M. W. et al. Restoring acid-sensing ion channel-1a in the amygdala of knock-out mice rescues fear memory but not unconditioned fear responses. J. Neurosci. 28, 13738–13741 (2008)

    Article  CAS  Google Scholar 

  11. Krishtal, O. The ASICs: signaling molecules? Modulators? Trends Neurosci. 26, 477–483 (2003)

    Article  CAS  Google Scholar 

  12. Xiong, Z. G. et al. Neuroprotection in ischemia: blocking calcium-permeable acid-sensing ion channels. Cell 118, 687–698 (2004)

    Article  CAS  Google Scholar 

  13. Yermolaieva, O., Leonard, A. S., Schnizler, M. K., Abboud, F. M. & Welsh, M. J. Extracellular acidosis increases neuronal cell calcium by activating acid-sensing ion channel 1a. Proc. Natl Acad. Sci. USA 101, 6752–6757 (2004)

    Article  CAS  ADS  Google Scholar 

  14. Schild, L. The epithelial sodium channel and the control of sodium balance. Biochim. Biophys. Acta 1802, 1159–1165 (2010)

    Article  CAS  Google Scholar 

  15. Snyder, P. M. et al. Mechanism by which Liddle’s syndrome mutations increase activity of a human epithelial Na+ channel. Cell 83, 969–978 (1995)

    Article  CAS  Google Scholar 

  16. Chang, S. S. et al. Mutations in subunits of the epithelial sodium channel cause salt wasting with hyperkalaemic acidosis, pseudohypoaldosteronism type 1. Nature Genet. 12, 248–253 (1996)

    Article  CAS  Google Scholar 

  17. Jasti, J., Furukawa, H., Gonzales, E. & Gouaux, E. Structure of acid-sensing ion channel 1 at 1.9 Å resolution and low pH. Nature 449, 316–323 (2007)

    Article  CAS  ADS  Google Scholar 

  18. Canessa, C. M., Horisberger, J.-D. & Rossier, B. C. Epithelial sodium channel related to proteins involved in neurodegeneration. Nature 361, 467–470 (1993)

    Article  CAS  ADS  Google Scholar 

  19. Palmer, L. G. Ion selectivity of the apical membrane Na channel in the toad urinary bladder. J. Membr. Biol. 67, 91–98 (1982)

    Article  CAS  Google Scholar 

  20. Lingueglia, E. et al. A modulatory subunit of acid sensing ion channels in brain and dorsal root ganglion cells. J. Biol. Chem. 272, 29778–29783 (1997)

    Article  CAS  Google Scholar 

  21. de Weille, J. R., Bassilana, F., Lazdunski, M. & Waldmann, R. Identification, functional expression and chromosomal localization of a sustained human proton-gated cation channel. FEBS Lett. 433, 257–260 (1998)

    Article  CAS  Google Scholar 

  22. Yagi, J., Wenk, H. N., Naves, L. A. & McCleskey, E. W. Sustained currents through ASIC3 ion channels at the modest pH changes that occur during myocardial ischemia. Circ. Res. 99, 501–509 (2006)

    Article  CAS  Google Scholar 

  23. Yu, Y. et al. A nonproton ligand sensor in the acid-sensing ion channel. Neuron 68, 61–72 (2010)

    Article  CAS  Google Scholar 

  24. Li, W. G., Yu, Y., Huang, C., Cao, H. & Xu, T. L. Nonproton ligand sensing domain is required for paradoxical stimulation of acid-sensing ion channel 3 (ASIC3) channels by amiloride. J. Biol. Chem. 286, 42635–42646 (2011)

    Article  CAS  Google Scholar 

  25. Springauf, A., Bresenitz, P. & Gründer, S. The interaction between two extracellular linker regions controls sustained opening of acid-sensing ion channel 1. J. Biol. Chem. 286, 24374–24384 (2011)

    Article  CAS  Google Scholar 

  26. Khakh, B. S. & Lester, H. A. Dynamic selectivity filters in ion channels. Neuron 23, 653–658 (1999)

    Article  CAS  Google Scholar 

  27. Waldmann, R., Champigny, G., Bassilana, F., Heurteaux, C. & Lazdunski, M. A proton-gated cation channel involved in acid-sensing. Nature 386, 173–177 (1997)

    Article  CAS  ADS  Google Scholar 

  28. Escoubas, P. et al. Isolation of a tarantula toxin specific for a class of proton-gated Na+ channels. J. Biol. Chem. 275, 25116–25121 (2000)

    Article  CAS  Google Scholar 

  29. Escoubas, P., Bernard, C., Lambeau, G., Lazdunski, M. & Darbon, H. Recombinant production and solution structure of PcTx1, the specific peptide inhibitor of ASIC1a proton-gated cation channels. Protein Sci. 12, 1332–1343 (2003)

    Article  CAS  Google Scholar 

  30. Chen, X., Kalbacher, H. & Gründer, S. The tarantula toxin psalmotoxin 1 inhibits acid-sensing ion channel (ASIC) 1a by increasing its apparent H+ affinity. J. Gen. Physiol. 126, 71–79 (2005)

    Article  CAS  Google Scholar 

  31. Chen, X., Kalbacher, H. & Gründer, S. Interaction of acid-sensing ion channel (ASIC) 1 with the tarantula toxin psalmotoxin 1 is state dependent. J. Gen. Physiol. 127, 267–276 (2006)

    Article  CAS  Google Scholar 

  32. Samways, D. S., Harkins, A. B. & Egan, T. M. Native and recombinant ASIC1a receptors conduct negligible Ca2+ entry. Cell Calcium 45, 319–325 (2009)

    Article  CAS  Google Scholar 

  33. Mazzuca, M. et al. A tarantula peptide against pain via ASIC1a channels and opioid mechanisms. Nature Neurosci. 10, 943–945 (2007)

    Article  CAS  Google Scholar 

  34. Salinas, M. et al. The receptor site of the spider toxin PcTx1 on the proton-gated cation channel ASIC1a. J. Physiol. (Lond.) 570, 339–354 (2006)

    Article  CAS  Google Scholar 

  35. Saez, N. J. et al. A dynamic pharmacophore drives the interaction between psalmotoxin-1 and the putative drug target acid-sensing ion channel 1a. Mol. Pharmacol. 80, 796–808 (2011)

    Article  CAS  Google Scholar 

  36. Pietra, F. Docking and MD simulations of the interaction of the tarantula peptide psalmotoxin-1 with ASIC1a channels using a homology model. J. Chem. Inf. Model. 49, 972–977 (2009)

    Article  CAS  Google Scholar 

  37. Sherwood, T. et al. Identification of protein domains that control proton and calcium sensitivity of ASIC1a. J. Biol. Chem. 284, 27899–27907 (2009)

    Article  CAS  Google Scholar 

  38. Dawson, R. J. P. et al. Structure of the acid-sensin ion channel 1 in complex with the gating modifier Psalmotoxin 1. Nature Commun. 3, 936 (2012)

    Article  Google Scholar 

  39. Hattori, M. & Gouaux, E. Molecular mechanism of ATP binding and ion channel activation in P2X receptors. Nature 485, 207–212 (2012)

    Article  CAS  ADS  Google Scholar 

  40. Gonzales, E. B., Kawate, T. & Gouaux, E. Pore architecture and ion sites in acid-sensing ion channels and P2X receptors. Nature 460, 599–604 (2009)

    Article  CAS  ADS  Google Scholar 

  41. Cushman, K. A., Marsh-Haffner, J., Adelman, J. & McCleskey, E. W. A conformational change in the extracellular domain that accompanies desensitization of acid-sensing ion channel (ASIC) 3. J. Gen. Physiol. 129, 345–350 (2007)

    Article  CAS  Google Scholar 

  42. Li, T., Yang, Y. & Canessa, C. M. Asn415 in the β11-β12 linker decreases proton-dependent desensitization of ASIC1. J. Biol. Chem. 285, 31285–31291 (2010)

    Article  CAS  Google Scholar 

  43. Li, T., Yang, Y. & Canessa, C. M. Leu85 in the β1-β2 linker of ASIC1 slows activation and decreases the apparent proton affinity by stabilizing a closed conformation. J. Biol. Chem. 285, 22706–22712 (2010)

    Article  CAS  Google Scholar 

  44. Li, T., Yang, Y. & Canessa, C. M. Two residues in the extracellular domain convert a nonfunctional ASIC1 into a proton-activated channel. Am. J. Physiol. Cell Physiol. 299, C66–C73 (2010)

    Article  CAS  Google Scholar 

  45. Li, J., Sheng, S., Perry, C. J. & Kleyman, T. R. Asymmetric organization of the pore region of the epithelial sodium channel. J. Biol. Chem. 278, 13867–13874 (2003)

    Article  CAS  Google Scholar 

  46. Poët, M. et al. Exploration of the pore structure of a peptide-gated Na+ channel. EMBO J. 20, 5595–5602 (2001)

    Article  Google Scholar 

  47. Li, T., Yang, Y. & Canessa, C. M. Outlines of the pore in open and closed conformations describe the gating mechanism of ASIC1. Nat Commun. 2, 399 (2011)

    Article  ADS  Google Scholar 

  48. Waldmann, R., Champigny, G., Bassilana, F., Voilley, N. & Lazdunski, M. Molecular cloning and functional expression of a novel amiloride-sensitive Na+ channel. J. Biol. Chem. 270, 27411–27414 (1995)

    Article  CAS  Google Scholar 

  49. Hille, B. Ion Channels of Excitable Membranes (Sinauer Associates, 2001)

    Google Scholar 

  50. Li, T., Yang, Y. & Canessa, C. M. Asp433 in the closing gate of ASIC1 determines stability of the open state without changing properties of the selectivity filter or Ca2+ block. J. Gen. Physiol. 137, 289–297 (2011)

    Article  CAS  Google Scholar 

  51. Dukkipati, A., Park, H. H., Waghray, D., Fischer, S. & Garcia, K. C. BacMam system for high-level expression of recombinant soluble and membrane glycoproteins for structural studies. Protein Expr. Purif. 62, 160–170 (2008)

    Article  CAS  Google Scholar 

  52. Otwinowski, Z. & Minor, W. Processing of X-ray diffraction data collected in oscillation mode. Methods Enzymol. 276, 307–326 (1997)

    Article  CAS  Google Scholar 

  53. McCoy, A. J. Solving structures of protein complexes by molecular replacement with Phaser. Acta Crystallogr. D 63, 32–41 (2007)

    Article  CAS  Google Scholar 

  54. Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)

    Article  Google Scholar 

  55. Adams, P. D. et al. PHENIX: building new software for automated crystallographic structure determination. Acta Crystallogr. D 58, 1948–1954 (2002)

    Article  Google Scholar 

  56. Davis, I. W. et al. MolProbity: all-atom contacts and structure validation for proteins and nucleic acids. Nucleic Acids Res. 35, W375–W383 (2007)

    Article  ADS  Google Scholar 

  57. Smart, O. S., Neduvelil, J. G., Wang, X., Wallace, B. A. & Samsom, M. S. HOLE: a program for the analysis of the pore dimensions of ion channel structural models. J. Mol. Graph. 14, 354–360 (1996)

    Article  CAS  Google Scholar 

  58. Hayward, S. & Lee, R. A. Improvements in the analysis of domain motions in proteins from conformational change: DynDom version 1.50. J. Mol. Graph. Model. 21, 181–183 (2002)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We appreciate assistance in the initial characterization of the action of PcTx1 on chicken ASIC1a by D. Samways and T. Egan, mass spectrometry analysis by D. King, together with comments from C. Jahr and R. MacKinnon. We are grateful to K. C. Garcia, C. Lee and A. Goehring for assistance with protein expression in mammalian cells. We thank L. Vaskalis for assistance with figures, H. Owen for help with manuscript preparation, H. Krishnamurthy for assistance in initial data collection, and Gouaux lab members for helpful discussion. This work was supported by an individual National Research Service Award from the National Institute of Neurological Disorders and Stroke (I.B.) and by the NIH (E.G.). E.G. is an investigator with the Howard Hughes Medical Institute.

Author information

Authors and Affiliations

Authors

Contributions

I.B. and E.G. designed the project. I.B. performed protein purification, crystallography and electrophysiology. I.B. and E.G. wrote the manuscript.

Corresponding author

Correspondence to Eric Gouaux.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Table 1, Supplementary Figures 1-20 and legends for Supplementary Movies 1-2. (PDF 8864 kb)

Supplementary Movie 1

This movie shows the structural changes accompanying PcTx1 binding to the Δ13 construct at low pH (see Supplementary Information file for full legend). (MOV 10455 kb)

Supplementary Movie 2

This movie shows the structural changes accompanying PcTx1 binding to the Δ13 construct at high pH (see Supplementary Information file for full legend). (MOV 6413 kb)

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Baconguis, I., Gouaux, E. Structural plasticity and dynamic selectivity of acid-sensing ion channel–spider toxin complexes. Nature 489, 400–405 (2012). https://doi.org/10.1038/nature11375

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature11375

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing