Cell-Derived Plasma Membrane Vesicles Are Permeable to Hydrophilic Macromolecules

Area of Science:

• Biophysics
• Cell Biology
• Biochemistry

Background:

• Giant plasma membrane vesicles (GPMVs) mimic native plasma membranes.
• GPMVs offer experimental advantages over synthetic vesicles.
• GPMVs are used to study membrane properties and molecule interactions.

Purpose of the Study:

• To investigate the permeability of GPMVs to hydrophilic solutes.
• To determine if GPMVs are sealed or porous.
• To identify conditions for preparing sealed GPMVs.

Main Methods:

• Isolation of GPMVs from mammalian cells using standard preparations.
• Permeability assays using hydrophilic solutes up to 40 kDa.
• Comparison of GPMV permeability with synthetic giant unilamellar vesicles.
• Identification of preparation modifications to reduce GPMV poration.

Main Results:

• Most standard GPMVs are passively permeable to hydrophilic solutes.
• This leakiness is attributed to stable, heterogeneous pores formed during vesicle isolation.
• Synthetic giant unilamellar vesicles exhibit significantly lower permeability.
• Specific preparation conditions were identified to yield sealed GPMVs.

Conclusions:

• The assumption of GPMV sealing is often invalid.
• GPMV poration impacts interpretations of membrane studies, especially drug permeation.
• Optimized preparation methods enable the use of sealed GPMVs for reliable research.