Using green fluorescent proteins to detect protein aggregation in live cells

Green fluorescent protein (GFP) was first isolated from jellyfish in the early 1960s when researchers collected and processed thousands of jellyfish. Three decades later, other researchers cloned GFP and demonstrated that the GFP biosynthesis is compatible with other organisms. This made GFP the ideal fluorescent marker for in vivo studies.

The discovery of GFP illuminated many previously invisible biological processes, leading to leaps in the fields of molecular biology, cell biology and medicine.

Songtao Ye et al. provided an overview of the fluorescent mechanisms of GFP’s chromophore core and specifically explored the development and application of the expanding family of fluorescent protein derivatives. Fluorescent protein derivatives are the organic fluorescent molecules which resemble the chemical structure of fluorescent protein chromophore cores. These fluorophores are not confined within a protein and are therefore much simpler to modify for applications.

The authors examined the biological applications of these fluorophores, particularly for studying protein aggregation in live cells.

“We report on the protein aggregation process in live cells, in particular in the early stage, as these abnormal species are considered to cause a series of age-related diseases,” said author Xin Zhang.

They discussed an imaging method that used fluorophores which would turn on their fluorescence upon interaction with misfolded proteins.

“It surprised us that these fluorophores could be further modified to present different

‘sensitivities’ towards protein aggregation with different conformational states,” said author Songtao Ye.

As a result, the team was able to synthesize a library of fluorophore derivatives that have different colors and environmental sensitivities to detect and distinguish multi-step protein aggregation.

Source: “Principles, modulation, and applications of fluorescent protein chromophores,” by Songtao Ye, Yuqi Tang, and Xin Zhang. Chemical Physics Reviews (2022). The article can be accessed at https://doi.org/10.1063/5.0080417 .