Multiscale Simulations of Membrane Adhesion Mediated by CD47-SIRPα Complexes

Area of Science:

• Biophysics
• Computational Biology
• Cellular Biophysics

Background:

• Cell adhesion is crucial for biological functions like tissue formation and immune responses.
• Cell adhesion involves complex interactions across multiple length scales, from nanometers to micrometers.
• Accurate computer simulations of cell adhesion require multiscale modeling to capture essential physical processes.

Purpose of the Study:

• To develop and apply a multiscale modeling approach for studying cell membrane adhesion.
• To investigate the CD47-SIRPα binding process, which is immunologically significant.
• To explore both equilibrium and dynamic properties of adhering membranes across relevant length and time scales.

Main Methods:

• Synergistic use of coarse-grained molecular dynamics (MD) simulations.
• Mesoscale kinetic Monte Carlo (kMC) simulations.
• Integration of MD and kMC to cover length scales from 1 nm to 1 μm and time scales from 0.1 ns to 20 s.

Main Results:

• The multiscale simulations successfully reproduced existing experimental data on CD47-SIRPα mediated membrane adhesion.
• Quantitative predictions were made regarding binding-induced conformational changes in SIRPα.
• The study revealed membrane-mediated cooperativity and fluctuation-induced interactions in CD47-SIRPα complexes.

Conclusions:

• The developed multiscale approach provides a powerful tool for studying cell membrane adhesion.
• The findings offer valuable insights into the biophysics of CD47-SIRPα interactions.
• This methodology is adaptable for various membrane proteins and can generate data for experimental validation.