Functional factors in the red cell membrane: interactions between the membrane and its underlying skeleton

• Published in: Immunological investigations Vol. 24; no. 1-2; p. 187
• Main Authors: Anstee, D J, Hemming, N J, Tanner, M J
• Format: Journal Article
• Language: English
• Published: England 01.01.1995
• Subjects: Anion Exchange Protein 1, Erythrocyte - metabolism; Asia, Southeastern; Cytoskeletal Proteins; Cytoskeleton - metabolism; Elliptocytosis, Hereditary - blood; Elliptocytosis, Hereditary - immunology; Erythrocyte Membrane - immunology; Erythrocyte Membrane - metabolism; Erythrocytes - immunology; Erythrocytes - metabolism; Glycophorin - metabolism; Humans; Membrane Proteins - blood; Membrane Proteins - immunology; Neuropeptides; Asia, Southeastern
• ISSN: 0882-0139
• DOI: 10.3109/08820139509062772

Recent studies involving two abnormal red cell phenotypes (South-east Asian ovalocytosis and Leach phenotype) provide novel information concerning the nature and significance of interactions of both the anion transport protein AE-1 (syn. band 3) and Glycophorins C and D with the underlying skeleton. The location of Wra and Dia blood group antigens to mutations on AE-1 at residues 658 and 854 respectively, together with the availability of monoclonal antibodies recognising epitopes dependent upon the integrity of the third extracellular loop of AE-1, have allowed us to study the organisation of the membrane domain of the mutant AE-1 found in South-east Asian ovalocytes (AE-1 SAO). The results suggest that the organisation of the whole membrane domain of AE-1 SAO is abnormal and that the organisation of other integral membrane proteins like those involved in expression of Rh blood group antigens may also be affected. Increased homo- and hetero-associations involving AE-1 SAO and other integral proteins may in turn result in reduced membrane flexibility. Purified protein 4.1 binds with 50-fold higher affinity to protein 4.1 depleted normal red cell membranes than to protein 4.1 depleted red cell membranes of Leach phenotype which lack Glycophorin C (GPC) and Glycophorin D (GPD). Experiments using purified protein 4.1 and p55 together with synthetic peptides corresponding to different regions of the cytoplasmic domain of Glycophorins C and D (GPC/D) demonstrate that protein 4.1 interacts directly with GPC through residues 82-98. They also show that p55 binds to GPC through residues 112-128. Since p55 also binds directly to protein 4.1 it is clear that protein 4.1 can bind to GPC through two different sites either directly through residues 82-98 or indirectly through p55. These results show that GPC and GPD provide major attachment sites for the red cell skeleton via protein 4.1 and that p55 is part of this complex.