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Updated: Dec 11, 2025
Characterization of Amyloid Structures in Aging C. Elegans Using Fluorescence Lifetime Imaging
Published on: March 27, 2020
Sequence-independent recognition of the amyloid structural motif by GFP protein family
Sherry C S Xu1,2, Josephine G LoRicco1,2, Anthony C Bishop1,2
1Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180.
Abstract:
Cnidarian fluorescent protein (FP) derivatives such as GFP, mCherry, and mEOS2 have been widely used to monitor gene expression and protein localization through biological imaging because they are considered functionally inert. We demonstrate that FPs specifically bind amyloid fibrils formed from many natural peptides and proteins. FPs do not bind other nonamyloid fibrillar structures such as microtubules or actin filaments and do not bind to amorphous aggregates. FPs can also bind small aggregates formed during the lag phase and early elongation phase of fibril formation and can inhibit amyloid fibril formation in a dose-dependent manner. These findings suggest caution should be taken in interpreting FP-fusion protein localization data when amyloid structures may be present. Given the pathological significance of amyloid-related species in some diseases, detection and inhibition of amyloid fibril formation using FPs can provide insights on developing diagnostic tools.
Insights
Fluorescent proteins (FPs) bind amyloid fibrils, not other aggregates. This interaction can inhibit amyloid formation, impacting imaging interpretations and offering diagnostic potential.
Area of Science:
- Biochemistry
- Molecular Biology
- Biophysics
Background:
- Cnidarian fluorescent proteins (FPs) like GFP are vital tools in biological imaging.
- They are generally assumed to be functionally inert, enabling accurate monitoring of gene expression and protein localization.
Purpose of the Study:
- To investigate the binding interactions of FPs with protein aggregates.
- To determine if FPs affect amyloid fibril formation.
Main Methods:
- Testing FP binding to various protein structures: amyloid fibrils, non-amyloid fibrils (microtubules, actin), and amorphous aggregates.
- Assessing the effect of FPs on amyloid fibril formation kinetics.
Main Results:
- FPs specifically bind to amyloid fibrils, but not to microtubules, actin filaments, or amorphous aggregates.
- FPs also bind to early-stage amyloid aggregates.
- FPs inhibit amyloid fibril formation in a dose-dependent manner.
Conclusions:
- Caution is advised when interpreting FP-fusion protein localization data in the presence of amyloid structures.
- FP interactions with amyloids offer potential for developing diagnostic tools for amyloid-related diseases.
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