Aluminum-altered membrane dynamics in human red blood cell white ghosts
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Published on: January 2, 2013
Abstract:
Fluorescence polarization of the hydrophobic membrane probe 1,6-diphenyl hexatriene was used to investigate alterations in membrane dynamics caused by micromolar concentrations of aluminum. Metal titration onto resealed white ghost membranes showed a progressive increase in steady-state fluorescence anisotropy of the probe in the presence of aluminum which was twice the value obtained upon titration of calcium. As calculated from steady-state fluorescence data in the presence and absence of 20 microM aluminum, a temperature dependent lipid order parameter indicated increased lipid packing. Motional dynamics of the probe molecule on the nanosecond time scale showed severe constraints in the presence of 20 microM aluminum as indicated by decreased rotational rate, decreased cone angle, and increased values of time resolved limiting anisotropy. Physiological consequences of altered membrane dynamics are also discussed.
Insights
Aluminum alters cell membrane dynamics by increasing lipid packing and restricting probe molecule motion. This study used fluorescence polarization to reveal aluminum
Area of Science:
- Biophysics
- Membrane Biophysics
- Biochemistry
Background:
- Cell membrane dynamics are crucial for cellular functions.
- Aluminum is a metal ion with potential biological effects.
- Understanding aluminum's impact on membranes is important for toxicology and cell biology.
Purpose of the Study:
- To investigate how aluminum affects the dynamics of cell membranes.
- To quantify the changes in membrane fluidity and lipid packing induced by aluminum.
Main Methods:
- Utilized fluorescence polarization with the hydrophobic probe 1,6-diphenyl hexatriene.
- Employed metal titration on resealed white ghost membranes.
- Analyzed steady-state and time-resolved fluorescence data.
Main Results:
- Micromolar concentrations of aluminum progressively increased fluorescence anisotropy, indicating altered membrane dynamics.
- Aluminum's effect on anisotropy was twice that of calcium.
- Temperature-dependent lipid order parameter showed increased lipid packing in the presence of aluminum.
- Aluminum significantly constrained the motional dynamics of the probe molecule.
Conclusions:
- Aluminum at micromolar concentrations induces significant changes in cell membrane structure and dynamics.
- Increased lipid packing and restricted molecular motion are key effects of aluminum on membranes.
- These findings have implications for understanding the physiological consequences of aluminum exposure.
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