Measuring ligand-cell surface receptor affinities with axial line-scanning fluorescence correlation spectroscopy

Abstract
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Article and author information

Abstract

Development and homeostasis of multicellular organisms is largely controlled by complex cell-cell signaling networks that rely on specific binding of secreted ligands to cell surface receptors. The Wnt signaling network, as an example, involves multiple ligands and receptors to elicit specific cellular responses. To understand the mechanisms of such a network, ligand-receptor interactions should be characterized quantitatively, ideally in live cells or tissues. Such measurements are possible using fluorescence microscopy yet challenging due to sample movement, low signal-to-background ratio and photobleaching. Here we present a robust approach based on fluorescence correlation spectroscopy with ultra-high speed axial line scanning, yielding precise equilibrium dissociation coefficients of interactions in the Wnt signaling pathway. Using CRISPR/Cas9 editing to endogenously tag receptors with fluorescent proteins, we demonstrate that the method delivers precise results even with low, near-native amounts of receptors.

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All data reported in the paper are included in the manuscript and/or supplementary Materials. Source data files have been provided for Figures 2, 5, 6 and 7.

Article and author information

Author details

Antonia Franziska Eckert

Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany

Competing interests
The authors declare that no competing interests exist.
Peng Gao

Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-5354-3944
Janine Wesslowski

Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany

Competing interests
The authors declare that no competing interests exist.
Xianxian Wang

Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany

Competing interests
The authors declare that no competing interests exist.
Jasmijn Rath

Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany

Competing interests
The authors declare that no competing interests exist.
Karin Nienhaus

Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany

Competing interests
The authors declare that no competing interests exist.
Gary Davidson

Institute of Biological and Chemical Systems, Karlsruhe Institute of Technology, Karlsruhe, Germany

For correspondence
gary.davidson@kit.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-2264-5518
Gerd Ulrich Nienhaus

Institute of Applied Physics, Karlsruhe Institute of Technology, Karlsruhe, Germany

For correspondence
uli@uiuc.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-5027-3192

Funding

Deutsche Forschungsgemeinschaft (SFB 1324,project A6,project Z2)

Gerd Ulrich Nienhaus

Deutsche Forschungsgemeinschaft (SFB 1324,project A6)

Gary Davidson

Helmholtz-Gemeinschaft (STN)

Gerd Ulrich Nienhaus

Helmholtz-Gemeinschaft (BIFTM)

Gary Davidson

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

Copyright

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.