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Fluorescence-Based Measurements of Phosphatidylserine/Phosphatidylinositol 4-Phosphate Exchange Between Membranes
Published on: March 14, 2021
Rho signaling participates in membrane fluidity homeostasis
Daniel Lockshon1, Carissa Perez Olsen, Christopher L Brett
1Department of Biochemistry, University of Washington, Seattle, Washington, United States of America.
Plos One
|October 17, 2012
Summary
Researchers discovered a new signaling pathway in yeast that controls cell membrane fluidity, impacting growth and adaptation. This pathway is crucial for eukaryotic cell division, differentiation, and environmental responses.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Biological membrane integrity and fluidity are vital for cellular homeostasis.
- While bacterial signaling pathways for lipid bilayer fluidity are known, none have been identified in eukaryotes.
- Eukaryotic cells require mechanisms to regulate membrane fluidity for essential functions.
Purpose of the Study:
- To identify signaling pathways that regulate membrane fluidity in eukaryotic cells.
- To investigate the role of specific fatty acids (oleic and palmitoleic acid) in influencing membrane fluidity and cell growth.
- To uncover novel components involved in eukaryotic membrane fluidity regulation.
Main Methods:
- Utilized yeast Saccharomyces cerevisiae mutants with differential growth responses to oleic and palmitoleic acid.
- Investigated strains deficient in cell wall integrity (CWI) pathway components, Pkc1, and Rho1.
- Identified Rho1 Guanine nucleotide Exchange Factor (GEF) Tus1 and GTPase Activating Protein (GAP) Sac7.
- Measured membrane fluidity using fluorescence anisotropy of TMA-DPH.
Main Results:
- Strains deficient in core CWI pathway components showed differential growth inhibition/stimulation by palmitoleate and oleate.
- Rho1 GEF (Tus1) and GAP (Sac7) were identified, independent of the CWI pathway.
- Key CWI pathway components (Rom2, Bem2, Rlm1) did not affect fatty acid sensitivity.
- Differential fatty acid effects on growth correlated with measured changes in plasma membrane fluidity.
Conclusions:
- This study provides the first evidence of a signaling pathway controlling membrane fluidity in eukaryotes.
- The identified pathway is essential for regulating membrane fluidity, impacting cell division, differentiation, and adaptation.
- Uncovers novel regulators of membrane fluidity, expanding our understanding of cellular homeostatic mechanisms.
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