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.

  • Letter
  • Published:

Allosteric modulation of the presynaptic Ca2+ sensor for vesicle fusion

Nature volume 435, pages 497–501 (2005)Cite this article

Abstract

Neurotransmitter release is triggered by an increase in the cytosolic Ca2+ concentration ([Ca2+]i), but it is unknown whether the Ca2+-sensitivity of vesicle fusion is modulated during synaptic plasticity. We investigated whether the potentiation of neurotransmitter release by phorbol esters1,2,3, which target presynaptic protein kinase C (PKC)/munc-13 signalling cascades4,5,6, exerts a direct effect on the Ca2+-sensitivity of vesicle fusion. Using direct presynaptic Ca2+-manipulation and Ca2+ uncaging at a giant presynaptic terminal, the calyx of Held, we show that phorbol esters potentiate transmitter release by increasing the apparent Ca2+-sensitivity of vesicle fusion. Phorbol esters potentiate Ca2+-evoked release as well as the spontaneous release rate. We explain both effects by an increased fusion ‘willingness’ in a new allosteric model of Ca2+-activation of vesicle fusion. In agreement with an allosteric mechanism, we observe that the classically high Ca2+ cooperativity in triggering vesicle fusion (∼ 4) is gradually reduced below 3 µM [Ca2+]i, reaching a value of <1 at basal [Ca2+]i. Our data indicate that spontaneous transmitter release close to resting [Ca2+]i is a consequence of an intrinsic property of the molecular machinery7,8 that mediates synaptic vesicle fusion.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

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

Figure 1: Potentiation of evoked EPSCs and miniature EPSC frequency by the phorbol ester PDBu.
Figure 2: Presynaptic Ca 2+ uncaging shows that phorbol ester increases the Ca 2+ sensitivity of vesicle fusion, concomitant with a reduced Ca 2+ cooperativity of vesicle fusion.
Figure 3: Transmitter release regulation by presynaptic [Ca2+]i close to resting values.
Figure 4: An allosteric model of Ca 2+ activation of vesicle fusion.

Similar content being viewed by others

References

  1. Malenka, R. C., Madison, D. V. & Nicoll, R. A. Potentiation of synaptic transmission in the hippocampus by phorbol ester. Nature 321, 175–177 (1986)

    Article  ADS  CAS  Google Scholar 

  2. Shapira, R., Silberberg, S. D., Ginsburg, S. & Rahamimoff, R. Activation of protein kinase C augments evoked transmitter release. Nature 325, 58–60 (1987)

    Article  ADS  CAS  Google Scholar 

  3. Yawo, H. Protein kinase C potentiates transmitter release from the chick ciliary presynaptic terminal by increasing the exocytotic fusion probability. J. Physiol. (Lond.) 515, 169–180 (1999)

    Article  CAS  Google Scholar 

  4. Hori, T., Takai, Y. & Takahashi, T. Presynaptic mechanism for phorbol ester-induced synaptic potentiation. J. Neurosci. 19, 7262–7267 (1999)

    Article  CAS  Google Scholar 

  5. Rhee, J.-S. et al. β phorbol ester- and diacylglycerol-induced augmentation of transmitter release is mediated by munc13s and not by PKCs. Cell 108, 121–133 (2002)

    Article  CAS  Google Scholar 

  6. Silinsky, E. M. & Searl, T. J. Phorbol esters and neurotransmitter release: More than just protein kinase C? Br. J. Pharmacol. 138, 1191–1201 (2003)

    Article  CAS  Google Scholar 

  7. Chen, Y. A. & Scheller, R. H. SNARE-mediated membrane fusion. Nature Rev. Mol. Cell Biol. 2, 98–106 (2001)

    Article  CAS  Google Scholar 

  8. Jahn, R., Lang, T. & Südhof, T. C. Membrane fusion. Cell 112, 519–533 (2003)

    Article  CAS  Google Scholar 

  9. Bollmann, J., Sakmann, B. & Borst, J. Calcium sensitivity of glutamate release in a calyx-type terminal. Science 289, 953–957 (2000)

    Article  ADS  CAS  Google Scholar 

  10. Schneggenburger, R. & Neher, E. Intracellular calcium dependence of transmitter release rates at a fast central synapse. Nature 406, 889–893 (2000)

    Article  ADS  CAS  Google Scholar 

  11. Felmy, F., Neher, E. & Schneggenburger, R. Probing the intracellular calcium sensitivity of transmitter release during synaptic facilitation. Neuron 37, 801–811 (2003)

    Article  CAS  Google Scholar 

  12. Wu, X. S. & Wu, L. G. Protein kinase C increases the apparent affinity of the release machinery to Ca2+ by enhancing the release machinery downstream of the Ca2+ sensor. J. Neurosci. 21, 7928–7936 (2001)

    Article  CAS  Google Scholar 

  13. Ishikawa, T., Sahara, Y. & Takahashi, T. A single packet of transmitter does not saturate postsynaptic glutamate receptors. Neuron 34, 613–621 (2002)

    Article  CAS  Google Scholar 

  14. Gillis, K. D., Mößner, R. & Neher, E. Protein kinase C enhances exocytosis from chromaffin cells by increasing the size of the readily releasable pool of secretory granules. Neuron 16, 1209–1220 (1996)

    Article  CAS  Google Scholar 

  15. Stevens, C. F. & Sullivan, J. M. Regulation of the readily releasable vesicle pool by protein kinase C. Neuron 21, 885–893 (1998)

    Article  CAS  Google Scholar 

  16. Sakaba, T. & Neher, E. Calmodulin mediates rapid recruitment of fast-releasing synaptic vesicles at a calyx-type synapse. Neuron 32, 1119–1131 (2001)

    Article  CAS  Google Scholar 

  17. Deitcher, D. L. et al. Distinct requirements for evoked and spontaneous release of neurotransmitter are revealed by mutations in the Drosophila gene neuronal-synaptobrevin. J. Neurosci. 18, 2028–2039 (1998)

    Article  CAS  Google Scholar 

  18. Schoch, S. et al. SNARE function analyzed in synaptobrevin/VAMP knockout mice. Science 294, 1117–1122 (2001)

    Article  ADS  CAS  Google Scholar 

  19. Washbourne, P. et al. Genetic ablation of the t-SNARE SNAP-25 distinguishes mechanisms of neuroexocytosis. Nature Neurosci. 5, 19–26 (2002)

    Article  CAS  Google Scholar 

  20. Yang, Y., Udayasankar, S., Dunning, J., Chen, P. & Gillis, K. D. A highly Ca2+-sensitive pool of vesicles is regulated by protein kinase C in adrenal chromaffin cells. Proc. Natl Acad. Sci. USA 99, 17060–17065 (2002)

    Article  ADS  CAS  Google Scholar 

  21. Monod, J., Wyman, J. & Changeux, J.-P. On the nature of allosteric transitions: A plausible model. J. Mol. Biol. 12, 88–118 (1965)

    Article  CAS  Google Scholar 

  22. Li, J., Zagotta, W. N. & Lester, H. A. Cyclic nucleotide-gated channels: structural basis of ligand efficacy and allosteric modulation. Q. Rev. Biophys. 30, 177–193 (1997)

    Article  CAS  Google Scholar 

  23. Zhu, H., Hille, B. & Xu, T. Sensitization of regulated exocytosis by protein kinase C. Proc. Natl Acad. Sci. USA 99, 17055–17059 (2002)

    Article  ADS  CAS  Google Scholar 

  24. Stevens, C. F. & Wesseling, J. F. Augmentation is a potentiation of the exocytotic process. Neuron 22, 139–146 (1999)

    Article  CAS  Google Scholar 

  25. Scanziani, M., Capogna, M., Gähwiler, B. H. & Thompson, S. M. Presynaptic inhibition of miniature excitatory synaptic currents by baclofen and adenosine in the hippocampus. Neuron 9, 919–927 (1992)

    Article  CAS  Google Scholar 

  26. Piedras-Rentería, E. S. et al. Presynaptic homeostasis at CNS nerve terminals compensates for lack of a key Ca2+ entry pathway. Proc. Natl Acad. Sci. USA 101, 3609–3614 (2004)

    Article  ADS  Google Scholar 

  27. Delaney, K. R. & Tank, D. W. A quantitative measurement of the dependence of short-term synaptic enhancement on presynaptic residual calcium. J. Neurosci. 14, 5885–5902 (1994)

    Article  CAS  Google Scholar 

  28. Angleson, J. K. & Betz, W. J. Intraterminal Ca2+ and spontaneous transmitter release at the frog neuromuscular junction. J. Neurophysiol. 85, 287–294 (2001)

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank E. Neher for discussions, and P. Ascher, F. Felmy, E. Neher, T. Sakaba and M. Wölfel for comments on the manuscript. This work was supported by the Deutsche Forschungsgemeinschaft (DFG). R.S. is a Heisenberg fellow of the DFG.

Author information

Author notes

  1. Volker Scheuss

    Present address: Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York, 11724, USA

Authors and Affiliations

  1. AG Synaptische Dynamik und Modulation und Abt. Membranbiophysik, Max-Planck-Institut für biophysikalische Chemie, Am Fassberg 11, D-37077, Göttingen, Germany

    Xuelin Lou, Volker Scheuss & Ralf Schneggenburger

Authors
  1. Xuelin Lou
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Volker Scheuss
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Ralf Schneggenburger
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Ralf Schneggenburger.

Ethics declarations

Competing interests

Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Figures

This file contains Supplementary Figures S1 and S2 and accompanying legends. Supplementary Figure S1 shows that EPSCs evoked by Ca2+-uncaging, and by brief presynaptic depolarizations are potentiated with a similar time-course by 1 µM PDBu, but the potentiation is transient under conditions of presynaptic whole-cell recording. Supplementary Figure S2 shows that EPSCs evoked by brief, and by prolonged presynaptic depolarizations are potentiated differentially by 1 µM PDBu, suggesting that the size of a readily-releasable vesicle pool is unchanged by PDBu. Furthermore, Ca2+-currents evoked by brief presynaptic depolarizations are slightly (∼15 %) increased by 1 µM PDBu. (DOC 1144 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Lou, X., Scheuss, V. & Schneggenburger, R. Allosteric modulation of the presynaptic Ca2+ sensor for vesicle fusion. Nature 435, 497–501 (2005). https://doi.org/10.1038/nature03568

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature03568

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

Advanced 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