Inhomogeneous membrane receptor diffusion explained by a fractional heteroscedastic time series model

Area of Science:

• Biophysics
• Cell Biology
• Statistical Mechanics

Background:

• Single particle tracking reveals heterogeneous cell membrane environments.
• Cell membrane component motion can exhibit subdiffusion and nonergodic behavior.

Purpose of the Study:

• To model inhomogeneous diffusion in cell membranes.
• To explain changes in diffusivity observed in cell membrane dynamics.

Main Methods:

• Utilizing an Autoregressive Fractionally Integrated Moving Average (ARFIMA) process to model anomalous diffusion.
• Incorporating Generalized Autoregressive Conditional Heteroscedasticity (GARCH) to represent fluctuating diffusion parameters.
• Applying these statistical models to single particle tracking data from cell membranes.

Main Results:

• The combined ARFIMA-GARCH model successfully describes inhomogeneous diffusion.
• The ARFIMA component captures anomalous diffusion patterns.
• The GARCH component accounts for the variability in the diffusion coefficient.

Conclusions:

• The ARFIMA-GARCH model provides a robust framework for understanding cell membrane dynamics.
• This approach elucidates the interplay between anomalous diffusion and fluctuating diffusivity.
• The findings offer insights into the physical mechanisms governing membrane component movement.