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Dual-Color Fluorescence Cross-Correlation Spectroscopy to Study Protein-Protein Interaction and Protein Dynamics in Live Cells
Published on: December 11, 2021
Cross-talk-free fluorescence cross-correlation spectroscopy by the switching method.
Yasuo Takahashi1, Junichi Nishimura, Akemi Suzuki
1Olympus Corporation, Tokyo, Japan. yas_takahashi@ot.olympus.co.jp
Cell Structure and Function
|October 22, 2008
Summary
A new switching Fluorescence Cross-Correlation Spectroscopy (FCCS) method reduces false positives from spectral overlap. This technique enables more reliable analysis of molecular interactions, such as protein cleavage in living cells.
Area of Science:
- Biophysics
- Molecular Biology
- Cell Biology
Background:
- Fluorescence Cross-Correlation Spectroscopy (FCCS) analyzes molecular interactions using dual-color laser excitation and detection.
- Conventional FCCS is susceptible to false-positive results due to spectral overlap between fluorophores.
- This spectral cross-talk limits the accuracy of molecular interaction analysis in complex biological systems.
Purpose of the Study:
- To develop and validate a novel switching FCCS system to overcome spectral cross-talk limitations.
- To demonstrate the feasibility of the enhanced FCCS technique for studying enzymatic protein cleavage in living cells.
- To improve the reliability and accuracy of molecular interaction measurements using FCCS.
Main Methods:
- Implemented a switching FCCS system utilizing an acousto-optic tunable filter (AOTF) for alternate laser excitation.
- Expressed a fusion protein containing EGFP and mRFP with a caspase-3 cleavage site in HeLa cells.
- Performed a proteolysis assay during apoptotic cell death, monitoring molecular interactions with the switching FCCS.
Main Results:
- The switching FCCS system effectively eliminated spectral cross-talk between the two fluorophores (EGFP and mRFP).
- A significant change in relative cross-correlation amplitude was observed upon enzymatic cleavage of the fusion protein.
- The absence of cross-talk signals led to a more pronounced and reliable detection of molecular events.
Conclusions:
- Switching FCCS provides a robust method for analyzing molecular interactions by eliminating spectral overlap artifacts.
- This advanced FCCS technique enables more accurate and reliable measurements of dynamic biological processes, like enzymatic cleavage.
- The developed switching FCCS system offers enhanced capabilities for in vivo molecular interaction studies.
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