Lipid Bilayer Composition Regulates Function of Lipid Rafts in Model Cell Membranes

02/07/2013

Driven by demixing of saturated and unsaturated lipids, biomimetic membranes form compositionally distinct domains. Neutron scattering data show larger domains as thickness mismatch increases between the domain and the adjacent membrane, implying that line tension plays a role in controlling membrane raft size. Domains of ~10 nm are found at equilibrium. [Cover image May 8, 2013, Volume 135, Issue 18, reprinted with permission from the Journal of the American Chemical Society.

Floating freely in cell membranes, lipid rafts are organizing centers for membrane-mediated processes. Neutron scattering techniques were used to characterize lipid domain size transitions from nanometers to micrometers in a four-component biomimetic lipid mixture. Results suggest that reversible changes in lipid composition may regulate the size of functional domains in lipid rafts. The BioSANS instrument at the ORNL Center for Structural Molecular Biology and the EQ-SANS instrument (BER) at the ORNL Spallation Neutron Source (BES) were used in this study.

Funding Acknowledgements

Support: Laboratory Directed Research and Development Program of Oak Ridge National Laboratory (ORNL; to J.K. and R.F.S.), managed by UT-Battelle, LLC, for the U.S. Department of Energy (DOE), and from National Science Foundation (NSF) research award MCB 0842839 (to G.W.F.). Additional support: Office of Biological and Environmental Research (OBER), DOE Office of Science, for BioSANS instrument at ORNL Center for Structural Molecular Biology (CSMB), and from the DOE Office of Basic Energy Sciences (OBES) Scientific User Facilities (SUF) Division, for the EQ-SANS instrument at the ORNL Spallation Neutron Source (SNS). These facilities are managed for DOE by UT-Battelle, LLC, under Contract No. DE-AC05-00OR2275. A portion of this research conducted using resources of Cornell Center for Advanced Computing, which receives funding from Cornell University; NSF; and other leading public agencies, foundations, and corporations.

References

Heberle F.A., Petruzielo R.S., Pan J., Drazba P., Kucerka N., Standaert R.F., Feigenson G.W., Katsaras J., “Bilayer thickness mismatch controls domain size in model membranes”, Journal of the American Chemical Society, 135, 18, 6853-6859 (2013). DOI: 10.1021/ja3113615