1. Structural Biology and Molecular Biophysics
  2. Neuroscience
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Super-resolution imaging of synaptic and extra-synaptic AMPA receptors with different-sized fluorescent probes

  1. Sang Hak Lee
  2. Chaoyi Jin
  3. En Cai
  4. Pinghua Ge
  5. Yuji Ishitsuka
  6. Kai Wen Teng
  7. Andre A de Thomaz
  8. Duncan L Nall
  9. Murat Baday
  10. Okunola Jeyifous
  11. Daniel Demonte
  12. Christopher M Dundas
  13. Sheldon Park
  14. Jary Y Delgado
  15. William N Green
  16. Paul R Selvin  Is a corresponding author
  1. University of Illinois at Urbana-Champaign, United States
  2. University of California, San Francisco, United States
  3. University of Illinois at Urbana Champaign, United States
  4. University of Campinas, Brazil
  5. University of Chicago, United States
  6. State University of New York, United States
  7. University of Texas, United States
Research Article
  • Cited 17
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Cite this article as: eLife 2017;6:e27744 doi: 10.7554/eLife.27744

Abstract

Previous studies tracking AMPA receptor (AMPAR) diffusion at synapses observed a large mobile extrasynaptic AMPAR pool. Using super-resolution microscopy, we examined how fluorophore size and photostability affected AMPAR trafficking outside of, and within, post-synaptic densities (PSDs) from rats. Organic fluorescent dyes (≈4 nm), quantum dots, either small (≈10 nm diameter; sQDs) or big (>20 nm; bQDs), were coupled to AMPARs via different-sized linkers. We find that >90% of AMPARs labeled with fluorescent dyes or sQDs were diffusing in confined nanodomains in PSDs, which were stable for 15 minutes or longer. Less than 10% of sQD-AMPARs were extrasynaptic and highly mobile. In contrast, 5–10% of bQD-AMPARs were in PSDs and 90-95% were extrasynaptic as previously observed. Contrary to the hypothesis that AMPAR entry is limited by the occupancy of open PSD "slots", our findings suggest that AMPARs rapidly enter stable "nanodomains" in PSDs with lifetime ≥15 minutes, and do not accumulate in extrasynaptic membranes.

Article and author information

Author details

  1. Sang Hak Lee

    Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Chaoyi Jin

    Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. En Cai

    University of California, San Francisco, San Francisco, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Pinghua Ge

    Department of Physics, University of Illinois at Urbana Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Yuji Ishitsuka

    Department of Physics, University of Illinois at Urbana Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Kai Wen Teng

    Department of Physics, University of Illinois at Urbana Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Andre A de Thomaz

    Institute of Physics Gleb Wataghin"", University of Campinas, Campinas, Brazil
    Competing interests
    The authors declare that no competing interests exist.
  8. Duncan L Nall

    Department of Physics, University of Illinois at Urbana Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Murat Baday

    Department of Physics, University of Illinois at Urbana Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  10. Okunola Jeyifous

    Department of Neurobiology, University of Chicago, Chicago, United States
    Competing interests
    The authors declare that no competing interests exist.
  11. Daniel Demonte

    Department of Chemical and Biological Engineering, State University of New York, Buffalo, United States
    Competing interests
    The authors declare that no competing interests exist.
  12. Christopher M Dundas

    Department of Chemical Engineering, University of Texas, Austin, United States
    Competing interests
    The authors declare that no competing interests exist.
  13. Sheldon Park

    Department of Chemical and Biological Engineering, State University of New York, Buffalo, United States
    Competing interests
    The authors declare that no competing interests exist.
  14. Jary Y Delgado

    Department of Neurobiology, University of Chicago, Chicago, United States
    Competing interests
    The authors declare that no competing interests exist.
  15. William N Green

    Department of Neurobiology, University of Chicago, Chicago, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-2167-1391
  16. Paul R Selvin

    Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States
    For correspondence
    selvin@illinois.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3658-4218

Funding

National Institutes of Health (NIH NS090903)

  • William N Green
  • Paul R Selvin

National Science Foundation (PHY-1430124)

  • Paul R Selvin

National Science Foundation (CBET-1264051)

  • Sheldon Park

National Institutes of Health (NIH NS100019)

  • William N Green
  • Paul R Selvin

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

Ethics

Animal experimentation: Primary hippocampal cultures were prepared from E18 rats according to UIUC guidelines. All rats were handled according to approved institutional animal care and use committee (IACUC) protocols (#15254) of UIUC.

Reviewing Editor

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

Publication history

  1. Received: April 14, 2017
  2. Accepted: July 26, 2017
  3. Accepted Manuscript published: July 27, 2017 (version 1)
  4. Version of Record published: August 30, 2017 (version 2)
  5. Version of Record updated: November 8, 2017 (version 3)

Copyright

© 2017, Lee 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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