Simultaneous Tracing of Protein Vicinal Dithiols in Live Cells Using an “Off-on” Fluorescent Probe

12 December 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Vicinal dithiol-containing proteins (VDPs) are of considerable importance due to their role in regulating cellular functions through the reversible dithiol/disulfide inter-conversion reaction. However, there are currently no effective tools for the simultaneous tracing of endogenous VDPs in live cells. Here, we report an “off-on” fluorescent probe (RhQ) for the selective detection of VDPs and illustrate its utility for the long-term tracing of protein vicinal dithiols with simultaneous fluorescence imaging in various cell lines. Importantly, our study provides the first-time valuable insight into the localization of VDPs in whole cells, dynamically visualizing that presence of cell-surface protein vicinal dithiols in MCF-7 cells. Interestingly, some functional cell-surface VDPs have been reported for MCF-7 cells using proteomic analysis. Furthermore, the gradually released fluorescence from RhQ after its interaction with VDPs provides an overall picture of the cellular protein vicinal dithiol profile for different cell lines. This technology shows great promise as a visualization tool for revealing the role of cellular protein vicinal dithiols, especially VDPs on the cell-surface, and stimulating the design of VDP related drug candidates and vectors.

Keywords

Vicinal-dithiol-containing proteins
Live cell imaging
fluorescent probe
Proteomic
Dynamic tracing

Supplementary materials

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Supplementary Material
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Materials and Apparatus, Synthetic procedure, Photophysical characterisation, pH titration, Effect of redox reagents on the fluorescence performance, Determination of fluorescence quantum yield, Fluorescence and absorbance response towards rBSA, Stability test for probe (RhQ) and control probe (HC) in HEPES buffer, 4. Cell toxicity assay for RhQ, Long-term tracing of VDPs with simultaneous fluorescence imaging in live cells, Cell culture, Protocols for simultaneous tracing of VDPs in live cells, SDS-PAGE and fluorescence imaging of gels, Mass spectrometry (MS)-based proteomics of binding proteins in MCF-7 cells, NMR and HRMS spectra of target probe (RhQ) and control probe (HC), References
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Movie S1a
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long-term tracing of VDPs in live MCF-7 cells with target probe RhQ.
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Movie S1b
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long-term tracing of VDPs in live MCF-7 cells with control probe HC.
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Movie S2a
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fluorescence dynamic imaging of VDPs in live MCF-7 cells within 20 min.
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Movie S2b
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fluorescence dynamic imaging of VDPs in live CHO-K1 cells within 20 min.
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Movie S2c
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fluorescence dynamic imaging of VDPs in live HeLa cells within 20 min.
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Movie S3.1a
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long-term tracing of VDPs in live MCF-7 cells with RhQ for 90 min-overlay.
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Movie S3.1b
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long-term tracing of VDPs in single live MCF-7 cell with RhQ for 90 min- three channels.
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Movie S3.2a
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long-term tracing of VDPs in live CHO-K1 cells with RhQ for 90 min-overlay.
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Movie S3.2b
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long-term tracing of VDPs in single live CHO-K1 cell with RhQ for 90 min- three channels.
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Movie S4.1a
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long-term tracing of VDPs in live MCF-7 cells with target probe RhQ after the cells were treated with DTNB.
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Movie S4.2a
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long-term tracing of VDPs in live MCF-7 cells with target probe RhQ after the cell were treated with NEM.
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