Contribution of the band 3-ankyrin interaction to erythrocyte membrane mechanical stability

Abstract

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.

Surface shape change during fusion of erythrocyte membranes is sensitive to membrane skeleton agents

“…6) that a pH of 7.4 and high ionic strength dramatically shifted upward, by about 5°C, the temperature needed to induce flat diaphragm breakdown into open lumens. Also, this finding is consistent with a report that lower pHs increase the band 3-ankyrin association (Low et al, 1991).…”

“…They also reported that, compared with a pH of 8.5, pHs from 8.0 to 6.5 cause an increase in the spectrin calorimetric transition by about 2-4°C (Brandts et al, 1978). Also, it has been reported that lower pHs increase the band 3-ankyrin association (Low et al, 1991). Therefore, compared with our conventional buffer, we desired to determine whether heat treatments carried out closer to a physiological pH and ionic strength would show protection against the heat treatmentinduced (assumed to take place through denaturation of spectrin) destabilization of flat diaphragms.…”

SLC4 base (HCO3−, CO32−) transporters: classification, function, structure, genetic diseases, and knockout models

“…The cytoplasmic domain of AE1 contains sites for binding ankyrin, 4.1 and 4.2 proteins, glyceraldehyde-3-phosphate dehydrogenase, phosphofructokinase, deoxyhemoglobin, p72syk protein tyrosine kinase, and hemichromes (230) and functions as an anchoring site for these membrane-associated proteins. These interactions are important for regulation of cell flexibility and shape (121), glucose metabolism (120), ion transport (124), and cell life span (95). The AE1 NH 2 -terminal cytoplasmic domain is stabilized by interlocked dimerization arms contributed by both monomers (230).…”

Infrared spectroscopic investigation of erythrocyte membrane-smoke interactions due to chronic cigarette smoking

“…Proteins in biological membranes can perturb the lipid environment and, depending on their nature and concentration, influence membrane fluidity (Chapman et al 1979;Szalontai et al 2003).The erythrocyte proteins are essential for the linkage connecting the membrane skeleton to the lipid bilayer, which is also essential for membrane stability (Lux et al 1978). The skeletal protein network appears to play a key role in the maintenance of the membrane's discoid shape and in restriction of the lateral mobility of its molecules (Goodman and Branton 1978;Low et al 1991). Amide I mode of vibration in the 1800-1600 cm -1 spectral region was used to study the protein secondary structure in infrared spectroscopy since this absorption is mainly associated with C=O stretching vibrations and it is suitable as a probe to determine the different secondary structures and polypeptides (Susi et al 1967;Lux 1979).…”