Metabolic Dependence of Protein Arrangement in Human Erythrocyte Membranes. I. Analysis of Spectrin-rich Complexes in ATP-depleted Red Cells

• Published in: Blood 1978-03, Vol.51 (3), p.385-395
• Main Authors: Palek, J., Liu, S.C., Snyder, L.M.
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - deficiency; Electrophoresis, Polyacrylamide Gel; Erythrocyte Membrane - metabolism; Erythrocytes - metabolism; Glucosephosphate Dehydrogenase Deficiency - blood; Humans; Membrane Proteins - metabolism; Molecular Weight; Peptides; Phenylhydrazines - pharmacology; Spectrin - metabolism; Time Factors
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V51.3.385.385

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 membranecytosol 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 (>106 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 >70% of the original ATP level. However, membranes of these cells did not contain the >106-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.