Distribution, lateral mobility and function of membrane proteins incorporated into giant unilamellar vesicles

Biophys J. 2005 Feb;88(2):1134-42. doi: 10.1529/biophysj.104.053413. Epub 2004 Dec 1.


GUVs have been widely used for studies on lipid mobility, membrane dynamics and lipid domain (raft) formation, using single molecule techniques like fluorescence correlation spectroscopy. Reports on membrane protein dynamics in these types of model membranes are by far less advanced due to the difficulty of incorporating proteins into GUVs in a functional state. We have used sucrose to prevent four distinct membrane protein(s) (complexes) from inactivating during the dehydration step of the GUV-formation process. The amount of sucrose was optimized such that the proteins retained 100% biological activity, and many proteo-GUVs were obtained. Although GUVs could be formed by hydration of lipid mixtures composed of neutral and anionic lipids, an alternate current electric field was required for GUV formation from neutral lipids. Distribution, lateral mobility, and function of an ATP-binding cassette transport system, an ion-linked transporter, and a mechanosensitive channel in GUVs were determined by confocal imaging, fluorescence correlation spectroscopy, patch-clamp measurements, and biochemical techniques. In addition, we show that sucrose slows down the lateral mobility of fluorescent lipid analogs, possibly due to hydrogen-bonding with the lipid headgroups, leading to larger complexes with reduced mobility.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP-Binding Cassette Transporters / analysis
  • ATP-Binding Cassette Transporters / chemistry
  • ATP-Binding Cassette Transporters / ultrastructure
  • Binding Sites
  • Desiccation
  • Escherichia coli Proteins / analysis
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / ultrastructure
  • Ion Channels / analysis
  • Ion Channels / chemistry
  • Ion Channels / ultrastructure
  • Lactococcus lactis / chemistry
  • Lipid Bilayers / chemistry*
  • Liposomes / chemistry*
  • Membrane Microdomains / chemistry*
  • Membrane Microdomains / ultrastructure*
  • Membrane Transport Proteins / analysis
  • Membrane Transport Proteins / chemistry*
  • Membrane Transport Proteins / ultrastructure*
  • Motion
  • Protein Binding
  • Sucrose / chemistry


  • ATP-Binding Cassette Transporters
  • Escherichia coli Proteins
  • Ion Channels
  • Lipid Bilayers
  • Liposomes
  • Membrane Transport Proteins
  • MscL protein, E coli
  • Sucrose
  • lactose permease