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Atomic Force Microscopy Imaging and Force Spectroscopy of Supported Lipid Bilayers
Published on: July 22, 2015
Electrostatic induction of lipid asymmetry
Krystal L Brown1, John C Conboy
1Department of Chemistry, University of Utah, 315 South 1400 East Room 2020, Salt Lake City, Utah 84112, USA.
Journal of the American Chemical Society
|May 21, 2011
Summary
Researchers demonstrated how electrostatic interactions can induce and maintain phosphatidylserine asymmetry in membranes. This finding sheds light on the fundamental physical and chemical factors governing lipid asymmetry in eukaryotic plasma membranes.
Area of Science:
- Biochemistry
- Cell Biology
- Biophysics
Background:
- The asymmetric distribution of phospholipids in eukaryotic plasma membranes is crucial for cellular functions.
- The precise mechanisms, including the role of ATP-dependent translocases, in establishing and maintaining this lipid asymmetry are not fully understood.
Purpose of the Study:
- To provide direct, quantitative experimental evidence for the induction of lipid asymmetry using a model system.
- To elucidate the fundamental physical and chemical principles governing lipid compositional asymmetry in cell membranes.
Main Methods:
- Utilized planar supported membranes to model the plasma membrane.
- Employed electrostatic association of poly-l-lysine to induce lipid asymmetry.
- Quantitatively measured phosphatidylserine asymmetry using sum-frequency vibrational spectroscopy.
Main Results:
- Demonstrated that attractive electrostatic interactions between poly-l-lysine and phosphatidylserine are sufficient to induce lipid asymmetry.
- Showed that these electrostatic forces can also maintain the established asymmetric arrangement of phosphatidylserine.
- Provided quantitative measurements of phosphatidylserine asymmetry in response to poly-l-lysine.
Conclusions:
- Electrostatic interactions play a significant role in the establishment and maintenance of lipid asymmetry in membranes.
- These findings offer insights into the physical underpinnings of lipid asymmetry in the eukaryotic plasma membrane.
- The study provides a foundational understanding of factors contributing to membrane lipid organization.
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