Giant unilamellar vesicles (GUVs) are used as a model system for cell membranes, but challenges in incorporating proteins into the vesicles have limited their use in studying proteomembrane interactions.

Frederic Pincet, Centre National de la Recherche Scientifique (CNRS), Paris, France, and colleagues used osmotic shock as a simple method to break open protein-containing liposomes (proteoliposomes) and re-form them into larger vesicles. The GUVs are formed by hydrating the small dried proteoliposomes with pure water.

The method works under physiological conditions and with high protein concentrations. It allows precise control of the protein density, but does not permit controlling the orientation of the incorporated protein. The proteins remain functional after they are incorporated into the GUVs. First-generation vesicles can be put through multiple drying and rehydration cycles to form even larger vesicles. 

The researchers successfully incorporated two types of membrane protein and a channel protein into GUVs using this method. Production costs are low, and the resulting GUVs can be separated and micromanipulated easily.

• Formation of Giant Unilamellar Proteo-Liposomes by Osmotic Shock,
  Isabelle Motta, Andrea Gohlke, Vladimir Adrien, Feng Li, Hélène Gardavot, James E. Rothman, Frederic Pincet,
  Langmuir 2015.
  DOI: 10.1021/acs.langmuir.5b01173