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Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells
Published on: November 12, 2020
Vesicle diffusion close to a membrane: intermembrane interactions measured with fluorescence correlation spectroscopy
Minjoung Kyoung1, Erin D Sheets
1Department of Chemistry and The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Biophysical Journal
|October 22, 2008
Summary
Vesicle diffusion near membranes is influenced by buffer conditions and membrane composition. These factors can spatially restrict vesicle dynamics, potentially controlling membrane fusion and fission.
Area of Science:
- Biophysics
- Cell Biology
- Physical Chemistry
Background:
- Membrane fusion and fission are crucial cellular processes.
- The role of vesicle diffusion dynamics near membranes is not fully understood.
- Protein machinery is well-studied, but physical interactions require further investigation.
Purpose of the Study:
- To experimentally and theoretically investigate the dynamics of small vesicles near target membranes.
- To understand how vesicle diffusion is affected by proximity to planar bilayers.
- To explore the influence of environmental factors on vesicle-membrane interactions.
Main Methods:
- Total internal reflection-fluorescence correlation spectroscopy (TIR-FCS) was employed.
- Experimental data was compared with theoretical models of vesicle-membrane interactions.
- Vesicle dynamics were studied under varying ionic strength, pH, and lipid compositions.
Main Results:
- Vesicle diffusion was hindered by hydrodynamic drag near planar bilayers.
- Ionic strength, pH, and lipid composition significantly affected vesicle population distributions and diffusion kinetics.
- Effective surface charges on neutral bilayers were analyzed, showing potential for charge redistribution to modify dynamics.
Conclusions:
- Vesicle dynamics near membranes are sensitive to local physiological conditions.
- Altering salt concentration, lipid composition, and pH can spatially restrict vesicle diffusion.
- This provides a potential biophysical mechanism for controlling membrane fusion and fission dynamics.
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