1. Structural Biology and Molecular Biophysics
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A label-free approach to detect ligand binding to cell surface proteins in real time

  1. Verena Burtscher
  2. Matej Hotka
  3. Yang Li
  4. Michael Freissmuth
  5. Walter Sandtner  Is a corresponding author
  1. Medical University of Vienna, Austria
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Cite this article as: eLife 2018;7:e34944 doi: 10.7554/eLife.34944

Abstract

Electrophysiological recordings allow for monitoring the operation of proteins with high temporal resolution down to the single molecule level. This technique has been exploited to track either ion flow arising from channel opening or the synchronized movement of charged residues and/or ions within the membrane electric field. Here, we describe a novel type of current by using the serotonin transporter (SERT) as a model. We examined transient currents elicited on rapid application of specific SERT inhibitors. Our analysis shows that these currents originate from ligand binding and not from a long-range conformational change. The Gouy-Chapman model predicts that adsorption of charged ligands to surface proteins must produce displacement currents and related apparent changes in membrane capacitance. Here we verified these predictions with SERT. Our observations demonstrate that ligand binding to a protein can be monitored in real time and in a label-free manner by recording the membrane capacitance.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files. Source data files have been provided for Figures 1 and 5.

Article and author information

Author details

  1. Verena Burtscher

    Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
    Competing interests
    The authors declare that no competing interests exist.
  2. Matej Hotka

    Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
    Competing interests
    The authors declare that no competing interests exist.
  3. Yang Li

    Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
    Competing interests
    The authors declare that no competing interests exist.
  4. Michael Freissmuth

    Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
    Competing interests
    The authors declare that no competing interests exist.
  5. Walter Sandtner

    Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
    For correspondence
    walter.sandtner@meduniwien.ac.at
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3637-260X

Funding

Austrian Science Fund (P28090)

  • Walter Sandtner

Austrian Science Fund (F3510)

  • Michael Freissmuth

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

Reviewing Editor

  1. Baron Chanda, University of Wisconsin-Madison, United States

Publication history

  1. Received: January 9, 2018
  2. Accepted: April 25, 2018
  3. Accepted Manuscript published: April 26, 2018 (version 1)
  4. Version of Record published: June 7, 2018 (version 2)
  5. Version of Record updated: March 6, 2019 (version 3)

Copyright

© 2018, Burtscher 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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