Metabolic dependence of protein arrangement in human erythrocyte membranes.
I. Analysis of spectrin-rich complexes in ATP-depleted red cells
J Palek, SC Liu and LM Snyder
The discocyte-echinocyte transformation and the decrease in deformability
associated with red cell ATP depletion have been attributed to changes in
the physical properties of spectrin and actin, membrane proteins located at
the membrane-cytosol interface. We investigated the spontaneous formation
of spectrin-rich complexes in human erythrocyte membranes, employing
two-dimensional SDS- polyacrylamide gel electrophoresis. Membranes of red
cells depleted in ATP under aerobic conditions exhibited (1) an increase in
components 4.5 and 8 and globin subunits, (2) a spontaneous formation of
heterodimers of spectrin 1 + 2 and spectrin 2 + component 4.9, and (3) a
large molecular weight (greater than 10(6) daltons) protein complex with a
high spectrin to band 3 ratio. These complexes were dissociated with
dithiothreitol and were prevented by anaerobic incubation or the
maintenance of red cell ATP and GSH levels with glucose, adenine, and
inosine. The complexes 1 + 2 and 2 + 4.9 were also seen in
acetylphenylhydrazine-treated, glucose-6-phosphate dehydrogenase- deficient
fresh erythrocytes that showed marked GSH depletion but preserved greater
than 70% of the original ATP level. However, membranes of these cells did
not contain the greater 10(6) dalton aggregate with a high spectrin to band
3 ratio. We concluded that the formation of the latter complex results from
rearrangement of spectrin and other polypeptides in membranes of
ATP-depleted red cells. Under aerobic conditions, the rearranged proteins
undergo spontaneous intermolecular crosslinkings through disulfide
couplings.
Volume 51,
Issue 3,
pp. 385-395,
03/01/1978
Copyright © 1978 by The American Society of Hematology
