Dilation of fusion pores by crowding of SNARE proteins

  1. Zhenyong Wu
  2. Oscar D Bello
  3. Sathish Thiyagarajan
  4. Sarah Marie Auclair
  5. Wensi Vennekate
  6. Shyam S Krishnakumar
  7. Ben O'Shaughnessy
  8. Erdem Karatekin  Is a corresponding author
  1. School of Medicine, Yale University, United States
  2. Yale University, United States
  3. Columbia University, United States

Abstract

Hormones and neurotransmitters are released through fluctuating exocytotic fusion pores that can flicker open and shut multiple times. Cargo release and vesicle recycling depend on the fate of the pore, which may reseal or dilate irreversibly. Pore nucleation requires zippering between vesicle-associated v- and target membrane t-SNAREs, but the mechanisms governing the subsequent pore dilation are not understood. Here, we probed dilation of single fusion pores using v-SNARE-reconstituted ~23 nm diameter discoidal nanolipoprotein particles (vNLPs) as fusion partners with cells ectopically expressing cognate, 'flipped' t-SNAREs. Pore nucleation required a minimum of 2, and reached a maximum above ~4 copies per face, but the probability of pore dilation was far from saturating at 15 copies, the NLP capacity. Our experimental and computational results suggest SNARE availability may be pivotal in determining whether neurotransmitters or hormones are released through a transient (kiss & run) or an irreversibly dilating pore (full fusion).

Article and author information

Author details

  1. Zhenyong Wu

    Department of Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Oscar D Bello

    Nanobiology Institute, Yale University, West Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Sathish Thiyagarajan

    Department of Physics, Columbia University, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Sarah Marie Auclair

    Nanobiology Institute, Yale University, West Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Wensi Vennekate

    Department of Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Shyam S Krishnakumar

    Nanobiology Institute, Yale University, West Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6148-3251
  7. Ben O'Shaughnessy

    Department of Chemical Engineering, Columbia University, New York, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Erdem Karatekin

    Department of Cellular and Molecular Physiology, School of Medicine, Yale University, New Haven, United States
    For correspondence
    erdem.karatekin@yale.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5934-8728

Funding

National Institute of General Medical Sciences (R01GM108954)

  • Erdem Karatekin

Kavli Foundation (Neuroscience Scholar Award)

  • Erdem Karatekin

Deutsche Forschungsgemeinschaft (VE760/1-1)

  • Wensi Vennekate

National Institute of Diabetes and Digestive and Kidney Diseases (R01DK027044)

  • Shyam S Krishnakumar

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Axel T Brunger, Stanford University Medical Center, United States

Publication history

  1. Received: November 4, 2016
  2. Accepted: March 26, 2017
  3. Accepted Manuscript published: March 27, 2017 (version 1)
  4. Version of Record published: April 25, 2017 (version 2)

Copyright

© 2017, Wu et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Zhenyong Wu
  2. Oscar D Bello
  3. Sathish Thiyagarajan
  4. Sarah Marie Auclair
  5. Wensi Vennekate
  6. Shyam S Krishnakumar
  7. Ben O'Shaughnessy
  8. Erdem Karatekin
(2017)
Dilation of fusion pores by crowding of SNARE proteins
eLife 6:e22964.
https://doi.org/10.7554/eLife.22964

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