Fusion pore conductance: experimental approaches and theoretical algorithms

Area of Science:

• Biophysics
• Cell Biology
• Electrophysiology

Background:

• Membrane fusion is a critical cellular process involving pore formation and expansion.
• Time-resolved admittance measurements are used to study membrane fusion dynamics.
• Existing methods are susceptible to signal distortions from electrophysiological equipment.

Purpose of the Study:

• To introduce modified time-resolved admittance methods for accurate membrane fusion studies.
• To correct for attenuation and phase shifts caused by electrophysiological equipment.
• To enhance the measurement of fusion pore conductance and cell membrane parameters.

Main Methods:

• Developed and validated two new phase angle adjustment approaches for admittance measurements.
• Modified the multiple sine wave approach for calculating cell membrane parameters and fusion pore conductance.
• Introduced an algorithm for fusion pore conductance calculation with concurrent membrane resistance changes.

Main Results:

• Successfully corrected cell-pipette (source) admittance for equipment-induced signal distortions.
• Demonstrated accurate calculation of fusion pore conductance and resting potential.
• Analyzed the sensitivity of capacitance restoration to phase shift errors and proposed off-line correction.

Conclusions:

• The modified time-resolved admittance measurements provide a more accurate method for studying membrane fusion.
• The new approaches improve the reliability of fusion pore conductance and cell membrane parameter measurements.
• The technique is extendable for resting potential measurements and robust against concurrent resistance changes.