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Open AccessResearch article

The influence of membrane physical properties on microvesicle release in human erythrocytes

Laurie J Gonzalez email, Elizabeth Gibbons email, Rachel W Bailey email, Jeremy Fairbourn email, Thaothanh Nguyen email, Samantha K Smith email, Katrina B Best email, Jennifer Nelson email, Allan M Judd email and John D Bell email

Department of Physiology and Developmental Biology, Brigham Young University Provo, Utah 84602, USA

author email corresponding author email

PMC Biophysics 2009, 2:7doi:10.1186/1757-5036-2-7

Published: 24  August  2009

Abstract

Exposure of human erythrocytes to elevated intracellular calcium causes fragments of the cell membrane to be shed as microvesicles. This study tested the hypothesis that microvesicle release depends on microscopic membrane physical properties such as lipid order, fluidity, and composition. Membrane properties were manipulated by varying the experimental temperature, membrane cholesterol content, and the activity of the trans-membrane phospholipid transporter, scramblase. Microvesicle release was enhanced by increasing the experimental temperature. Reduction in membrane cholesterol content by treatment with methyl-β-cyclodextrin also facilitated vesicle shedding. Inhibition of scramblase with R5421 impaired vesicle release. These data were interpreted in the context of membrane characteristics assessed previously by fluorescence spectroscopy with environment-sensitive probes such as laurdan, diphenylhexatriene, and merocyanine 540. The observations supported the following conclusions: 1) calcium-induced microvesicle shedding in erythrocytes relates more to membrane properties detected by diphenylhexatriene than by the other probes; 2) loss of trans-membrane phospholipid asymmetry is required for microvesicle release.

PACS Codes: 87.16.dj, 87.16.dt

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