Fluorescent Visualization of Cellular Proton Fluxes

Area of Science:

• Cell Biology
• Biophysics
• Biochemistry

Background:

• Cells regulate internal and external pH using plasma membrane proton fluxes.
• Proton-coupled transport is crucial for metabolite and ion co-transport.
• Traditional electrical measurements offer limited insight into cell surface proton transport.

Purpose of the Study:

• To develop a novel method for visualizing voltage-dependent proton fluxes across the entire cell surface.
• To indirectly assess the activity of ion channels and transporters involved in proton movement.

Main Methods:

• Covalently attaching small-molecule fluorescent pH sensors to the cell's glycocalyx.
• Utilizing extracellularly facing sensors for real-time detection of proton accumulation and depletion at the plasma membrane.
• Correlating sensor-based measurements with whole-cell proton current.

Main Results:

• Successfully visualized voltage-dependent proton fluxes across the cell landscape.
• Demonstrated real-time detection of proton dynamics at the plasma membrane, reflecting channel and transporter activity.
• Observed propagation of proton wavefronts between adjacent cells.

Conclusions:

• The developed approach provides a powerful tool for visualizing proton transport at the cell surface.
• This method is adaptable for studying various electrogenic and non-electrogenic transport events.
• Enables a deeper understanding of cellular pH regulation and transport mechanisms.