Beyond analytic solution: Analysis of FRAP experiments by spatial simulation of the forward problem

Area of Science:

• Cellular and Molecular Biology
• Biophysics
• Computational Biology

Background:

• Fluorescence redistribution after photobleaching (FRAP) is vital for studying molecular dynamics.
• Analytical solutions for FRAP are limited in complex cellular geometries and behaviors.
• Accurate modeling is needed for diffusion and binding kinetics in cellular environments.

Purpose of the Study:

• To demonstrate numerical reaction-diffusion simulations for modeling FRAP experiments.
• To overcome limitations of analytical solutions in complex cellular geometries.
• To analyze molecular dynamics in various cellular compartments, including biomolecular condensates.

Main Methods:

• Utilized Virtual Cell software for numerical reaction-diffusion simulations.
• Performed parameter scans and varied bleaching parameters (location, size).
• Modeled diffusion and binding in membrane surfaces, cytosol, and phase-separated biomolecular condensates.

Main Results:

• Numerical simulations accurately model FRAP in complex geometries.
• The approach effectively brackets diffusion coefficients and kinetic rate constants.
• Successfully modeled diffusion and binding within biomolecular condensates as viscous domains.

Conclusions:

• Numerical simulations offer a robust alternative to analytical methods for FRAP analysis.
• This method enhances understanding of molecular dynamics in intricate cellular environments.
• The approach is applicable to diverse biological systems, including biomolecular condensates.