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Receptor activation alters inner surface potential during phagocytosis
Tony Yeung1, Mauricio Terebiznik, Liming Yu
1Division of Cell Biology, Hepatology, and Nutrition Department, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada.
Science (New York, N.Y.)
|July 22, 2006
Summary
Researchers developed genetically encoded probes to measure cell surface potential. They observed significant charge changes on macrophage membranes during phagocytosis, impacting signaling molecule interactions.
Area of Science:
- Cell biology
- Membrane biophysics
- Immunology
Background:
- Biological membrane surface potential is influenced by lipid composition.
- Understanding dynamic changes in membrane potential is crucial for cellular processes.
- Existing methods for assessing membrane potential in live cells are limited.
Purpose of the Study:
- To develop genetically encoded probes for measuring membrane surface potential in intact cells.
- To investigate alterations in plasma membrane charge during phagocytosis in macrophages.
- To elucidate the role of lipid remodeling in modulating membrane potential and its impact on signaling.
Main Methods:
- Development of genetically encoded fluorescent probes.
- Live-cell imaging of macrophage phagocytosis.
- Analysis of membrane lipid composition changes.
- Assessing the release of membrane-associated signaling proteins.
Main Results:
- Genetically encoded probes successfully measured localized changes in the inner plasma membrane surface potential of macrophages.
- Significant alterations in membrane charge were observed during phagocytosis, particularly at the phagosomal cup.
- Hydrolysis of phosphoinositides and phosphatidylserine displacement were identified as key contributors to the observed potential changes.
- Electrostatic interactions mediating the membrane targeting of signaling molecules (K-Ras, Rac1, c-Src) were disrupted, leading to their rapid release from altered membrane subdomains.
Conclusions:
- Genetically encoded probes provide a powerful tool for studying dynamic membrane potential changes in live cells.
- Lipid remodeling during phagocytosis dynamically alters macrophage plasma membrane surface potential.
- Changes in membrane surface charge significantly impact the localization and function of key signaling molecules involved in phagocytosis.
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