Imaging Activity-Dependent Signaling Dynamics at the Neuronal Synapse Using FRET-Based Biosensors

Area of Science:

• Neuroscience
• Cell Biology
• Biochemistry

Background:

• Studying intracellular signaling in small synaptic terminals is challenging.
• Existing methods lack the spatial and temporal resolution needed.
• Understanding presynaptic signaling is crucial for neuronal function.

Purpose of the Study:

• To introduce a novel method combining FRET biosensors and synaptic markers.
• To enable precise analysis of intracellular signaling pathways in neuronal synaptic terminals.
• To investigate the spatial and temporal dynamics of signaling molecules.

Main Methods:

• Utilizing FRET-based biosensors with specific donor/acceptor pairs.
• Employing the lipophilic styryl dye FM1-43 as a synaptic marker.
• Unmixing spectral fingerprints to differentiate signals.
• Using FM1-43 destaining to map synaptic activity for FRET analysis.
• Measuring cAMP dynamics using a CFP/YFP intramolecular FRET sensor.

Main Results:

• Demonstrated the successful application of the combined FRET and FM1-43 method.
• Successfully measured the temporal dynamics of cAMP at the presynaptic terminal.
• Validated the use of spectral unmixing for signal isolation.
• Showcased the ability to map synaptic activity for targeted FRET measurements.

Conclusions:

• The combined FRET biosensor and synaptic marker approach is effective for studying intracellular signaling in small synaptic terminals.
• This methodology offers high spatial and temporal resolution for analyzing signaling dynamics.
• The technique is versatile and applicable to various signaling processes and protein-protein interactions.