Green fluorescent proteins (GFPs) for measuring voltage.

Area of Science:

• Neuroscience
• Biotechnology
• Molecular Biology

Background:

• Studying neural information processing requires high-resolution measurement of signal transduction in cells.
• Existing methods for measuring cellular voltage have limitations in resolution and detectability.

Purpose of the Study:

• To design and characterize a novel genetically encoded voltage sensor for measuring transmembrane voltage in single cells.
• To improve the spatial and temporal resolution of signal transduction measurements in the nervous system.

Main Methods:

• A genetically encoded probe was engineered by fusing a modified green fluorescent protein (GFP) to a voltage-sensitive potassium (K+) channel.
• The voltage-dependent conformational changes in the K+ channel were designed to alter GFP fluorescence.

Main Results:

• The developed probe achieved a maximal fractional fluorescence change of 5.1%, comparable to leading organic voltage-sensitive dyes.
• The probe's signal is temporally expanded, making it 30-fold easier to detect than traditional linear dyes.
• The DNA-encoded sensor allows for noninvasive introduction and targeted delivery to specific cellular compartments.

Conclusions:

• Genetically encoded voltage sensors offer a powerful tool for noninvasive, high-resolution monitoring of neural activity.
• This novel GFP-based probe enhances the detectability of transmembrane voltage changes, advancing the study of neuronal signaling.