Contribution of the band 3-ankyrin interaction to erythrocyte membrane
mechanical stability
PS Low, BM Willardson, N Mohandas, M Rossi and S Shohet
Department of Chemistry, Purdue University, West Lafayette, IN 47907- 1393.
In an effort to evaluate the role of the band 3-ankyrin linkage in
maintenance of red blood cell membrane integrity, solution conditions were
sought that would selectively dissociate the band 3-ankyrin linkage,
leaving other membrane skeletal interactions intact. For this purpose
erythrocytes were equilibrated overnight in nutrient-containing buffers at
a range of elevated pHs and then examined for changes in mechanical
stability and membrane skeletal composition. Band 3 was found to be
released from interaction with the membrane skeleton over a pH range (8.4
to 9.5) that was observed to dissociate the band 3- ankyrin interaction in
vitro. In contrast, all other membrane skeletal associations appeared to
remain intact up to pH 9.3, after which they were also seen to dissociate.
Whereas hemolysis of mechanically unstressed cells did not begin until
approximately pH 9.3, where the membrane skeletons began to disintegrate,
enhanced fragmentation of shear stressed membranes was seen to begin near
pH 8, where band 3 dissociation was first observed. Furthermore, the
shear-induced fragmentation rate was found to reach a maximum at pH 9.4,
ie, where band 3 dissociation was essentially complete. Based on these
correlations, we hypothesize that the band 3-ankyrin linkage of the
membrane skeleton to the lipid bilayer is essential for red blood cell
stability in the face of mechanical distortion but not for cellular
integrity in the absence of mechanical stress.
Volume 77,
Issue 7,
pp. 1581-1586,
04/01/1991
Copyright © 1991 by The American Society of Hematology
