Remodeling the shape of the skeleton in the intact red cell

The role of the membrane skeleton in determining the shape of the human red cell was probed by weakening it in situ with urea, a membrane-permeable perturbant of spectrin. Urea by itself did not alter the biconcave disk shape of the red cell; however, above threshold conditions (1.5 M, 37 degrees C,...

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Bibliographic Details
Published in:Biophysical journal 1996-02, Vol.70 (2), p.1036-1044
Main Authors: Khodadad, J.K., Waugh, R.E., Podolski, J.L., Josephs, R., Steck, T.L.
Format: Article
Language:English
Subjects:
Biomechanical Phenomena
Biophysical Phenomena
Biophysics
Cell Size - drug effects
Cell Size - physiology
Elasticity
Erythrocyte Deformability - drug effects
Erythrocyte Deformability - physiology
Erythrocyte Membrane - chemistry
Erythrocyte Membrane - drug effects
Erythrocyte Membrane - ultrastructure
Humans
In Vitro Techniques
Lysophosphatidylcholines - pharmacology
Models, Biological
Urea - pharmacology
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Summary:The role of the membrane skeleton in determining the shape of the human red cell was probed by weakening it in situ with urea, a membrane-permeable perturbant of spectrin. Urea by itself did not alter the biconcave disk shape of the red cell; however, above threshold conditions (1.5 M, 37 degrees C, 10 min), it caused an 18% reduction in the membrane elastic shear modulus. It also potentiated the spiculation of cells by lysophosphatidylcholine. These findings suggest that the contour of the resting cell is not normally dependent on the elasticity of or tension in the membrane skeleton. Rather, the elasticity of the skeleton stabilizes membranes against deformation. Urea treatment also caused the projections induced both by micropipette aspiration and by lysophosphatidylcholine to become irreversible. Furthermore, urea converted the axisymmetric conical spicules induced by lysophosphatidylcholine into irregular, curved and knobby spicules; i.e., echinocytosis became acanthocytosis. Unlike controls, the ghosts and membrane skeletons obtained from urea-generated acanthocytes were imprinted with spicules. These data suggest that perturbing interprotein associations with urea in situ allowed the skeleton to evolve plastically to accommodate the contours imposed upon it by the overlying membrane.
ISSN:0006-3495
1542-0086
DOI:10.1016/S0006-3495(96)79649-2