Spatial Control of Arp2/3-Induced Actin Polymerization on Phase-Separated Giant Unilamellar Vesicles

Area of Science:

• Biophysics
• Cell Biology
• Materials Science

Background:

• Understanding cell shape dynamics is crucial for deciphering cellular functions.
• Biomimetic systems, particularly on giant unilamellar vesicles (GUVs), offer simplified models to study complex cellular processes like cytoskeletal dynamics.
• Reconstituting the intricate interplay between the cytoskeleton and membrane in vitro remains a significant experimental hurdle.

Purpose of the Study:

• To develop a controlled biomimetic system for studying actin-membrane interactions.
• To investigate how targeted actin polymerization influences the organization and deformation of phase-separated lipid domains within GUVs.
• To establish a foundation for creating protocells with autonomous reorganization and movement capabilities.

Main Methods:

• Utilized lipid-induced segregation of an actin polymerization activator to target specific domains within phase-separated GUVs.
• Reconstructed cytoskeletal dynamics on cell-sized GUVs to mimic in vitro cell-like processes.
• Observed actin network localization and induced membrane deformations in response to polymerization.

Main Results:

• Successfully targeted actin polymerization to liquid-ordered (Lo), liquid-disordered (Ld), or both types of domains in phase-separated GUVs.
• Demonstrated actin network formation localized to specific membrane domains.
• Observed actin polymerization inducing deformation and reorganization of these lipid domains within the GUVs.

Conclusions:

• The developed system enables precise control over actin polymerization at specific membrane domains within GUVs.
• This approach provides a powerful tool for studying the physical mechanisms of cytoskeleton-membrane interactions.
• The findings pave the way for future research into protocell development and autonomous cellular behaviors.