Charged Lipids Influence Phase Separation in Cell-Sized Liposomes Containing Cholesterol or Ergosterol

Area of Science:

• Biochemistry
• Cell Biology
• Membrane Biophysics

Background:

• Charged lipids and ions are crucial for cell membrane functions and signal transduction.
• Phase separation domains in cell membranes are key research areas for understanding cellular processes.
• Previous studies explored liposomes with charged lipids and cholesterol, and membrane models with ergosterol.

Purpose of the Study:

• To investigate how substituting cholesterol with ergosterol affects phase-separated domain structures in charged lipid membranes.
• To compare the influence of cholesterol versus ergosterol on membrane homogeneity and response to charged lipids.

Main Methods:

• Utilized cell-sized liposomes containing charged lipids.
• Substituted cholesterol with ergosterol in membrane models.
• Analyzed phase-separated domain structure alterations.

Main Results:

• Ergosterol incorporation led to increased homogeneity in membranes with charged lipids.
• Cholesterol-containing membranes exhibited greater sensitivity to charged states.
• Ergosterol-containing liposomes demonstrated reduced responses to charged lipids compared to cholesterol-containing ones.

Conclusions:

• Ergosterol promotes membrane homogeneity, unlike cholesterol, in the presence of charged lipids.
• Differences in membrane response to charged lipids between ergosterol and cholesterol have implications for cell signaling.
• Findings contribute to understanding variations between yeast and mammalian cells and lipid-protein interactions in signal transduction.