Otoferlin acts as a Ca2+ sensor for vesicle fusion and vesicle pool replenishment at auditory hair cell ribbon synapses

  1. Nicolas Antoine Michalski  Is a corresponding author
  2. Juan D Goutman
  3. Sarah Marie Auclair
  4. Jacques Boutet de Monvel
  5. Margot Tertrais
  6. Alice Emptoz
  7. Alexandre Parrin
  8. Sylvie Nouaille
  9. Marc Guillon
  10. Martin Sachse
  11. Danica Ciric
  12. Amel Bahloul
  13. Jean-Pierre Hardelin
  14. Roger Bryan Sutton
  15. Paul Avan
  16. Shyam S Krishnakumar
  17. James E Rothman
  18. Didier Dulon
  19. Saaid Safieddine
  20. Christine Petit  Is a corresponding author
  1. Institut Pasteur, France
  2. Universidad de Buenos Aires, Argentina
  3. Yale University School of Medicine, United States
  4. UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), France
  5. Université Paris Descartes, Sorbonne Paris Cité, France
  6. Texas Tech University Health Sciences Center, United States
  7. Université d'Auvergne, France

Abstract

Hearing relies on rapid, temporally precise, and sustained neurotransmitter release at the ribbon synapses of sensory cells, the inner hair cells (IHCs). This process requires otoferlin, a six C2-domain, Ca2+-binding transmembrane protein of synaptic vesicles. To decipher the role of otoferlin in the synaptic vesicle cycle, we produced knock-in mice (OtofAla515,Ala517/Ala515,Ala517) with lower Ca2+-binding affinity of the C2C domain. The IHC ribbon synapse structure, synaptic Ca2+ currents, and otoferlin distribution were unaffected in these mutant mice, but auditory brainstem response wave-I amplitude was reduced. Lower Ca2+ sensitivity and delay of the fast and sustained components of synaptic exocytosis were revealed by membrane capacitance measurement upon modulations of intracellular Ca2+ concentration, by varying Ca2+ influx through voltage-gated Ca2+-channels or Ca2+ uncaging. Otoferlin thus functions as a Ca2+ sensor, setting the rates of primed vesicle fusion with the presynaptic plasma membrane and synaptic vesicle pool replenishment in the IHC active zone.

Article and author information

Author details

  1. Nicolas Antoine Michalski

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    For correspondence
    nicolas.michalski@pasteur.fr
    Competing interests
    No competing interests declared.
  2. Juan D Goutman

    Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Universidad de Buenos Aires, Buenos Aires, Argentina
    Competing interests
    No competing interests declared.
  3. Sarah Marie Auclair

    Department of Cell Biology, Yale University School of Medicine, New Haven, United States
    Competing interests
    No competing interests declared.
  4. Jacques Boutet de Monvel

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  5. Margot Tertrais

    UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France
    Competing interests
    No competing interests declared.
  6. Alice Emptoz

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  7. Alexandre Parrin

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  8. Sylvie Nouaille

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  9. Marc Guillon

    Centre National de la Recherche Scientifique UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
    Competing interests
    No competing interests declared.
  10. Martin Sachse

    Center for Innovation and Technological Research, Ultrapole, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  11. Danica Ciric

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  12. Amel Bahloul

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  13. Jean-Pierre Hardelin

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  14. Roger Bryan Sutton

    Department of Cell Physiology and Molecular Biophysics, Texas Tech University Health Sciences Center, Lubbock, United States
    Competing interests
    No competing interests declared.
  15. Paul Avan

    Laboratoire de Biophysique Sensorielle, Université d'Auvergne, Clermont-Ferrand, France
    Competing interests
    No competing interests declared.
  16. Shyam S Krishnakumar

    Department of Cell Biology, Yale University School of Medicine, New Haven, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6148-3251
  17. James E Rothman

    Department of Cell Biology, Yale University School of Medicine, New Haven, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8653-8650
  18. Didier Dulon

    UMRS 1120, Institut National de la Santé et de la Recherche Médicale (INSERM), Paris, France
    Competing interests
    No competing interests declared.
  19. Saaid Safieddine

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    Competing interests
    No competing interests declared.
  20. Christine Petit

    Unité de Génétique et Physiologie de l'Audition, Institut Pasteur, Paris, France
    For correspondence
    christine.petit@pasteur.fr
    Competing interests
    Christine Petit, Reviewing editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9069-002X

Funding

Foundation Raymonde et Guy Strittmatter (Research project grant)

  • Christine Petit

Foundation BNP Parisbas (Research project grant)

  • Christine Petit

LHW-Stiftung (Research project grant)

  • Christine Petit

LabExLifesenses (ANR‐10‐LABX‐65)

  • Christine Petit

Investissements d'Avenir (ANR‐11‐IDEX‐0004‐02)

  • Christine Petit

Agir pour l'Audition (Prix Emergence scientifique)

  • Nicolas Antoine Michalski

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

Ethics

Animal experimentation: Animal experiments were carried out in accordance with European Community Council Directive 2010/63/UE under authorizations 2012-028, 2012-038, and 2014-005 from the Institut Pasteur ethics committee for animal experimentation.

Copyright

© 2017, Michalski 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. Nicolas Antoine Michalski
  2. Juan D Goutman
  3. Sarah Marie Auclair
  4. Jacques Boutet de Monvel
  5. Margot Tertrais
  6. Alice Emptoz
  7. Alexandre Parrin
  8. Sylvie Nouaille
  9. Marc Guillon
  10. Martin Sachse
  11. Danica Ciric
  12. Amel Bahloul
  13. Jean-Pierre Hardelin
  14. Roger Bryan Sutton
  15. Paul Avan
  16. Shyam S Krishnakumar
  17. James E Rothman
  18. Didier Dulon
  19. Saaid Safieddine
  20. Christine Petit
(2017)
Otoferlin acts as a Ca2+ sensor for vesicle fusion and vesicle pool replenishment at auditory hair cell ribbon synapses
eLife 6:e31013.
https://doi.org/10.7554/eLife.31013

Share this article

https://doi.org/10.7554/eLife.31013

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