Deficiency of protein 4.2 in erythrocytes from a patient with a Coombs negative hemolytic anemia. Evidence for a role of protein 4.2 in stabilizing ankyrin on the membrane.

摘要: A patient with a mild hemolytic anemia and osmotically fragile, spherocytic erythrocytes was studied. Analysis of the erythrocyte membrane proteins by SDS-PAGE revealed deficiency protein 4.2 (less than 0.10% normal). The 4.2-deficient contained normal amounts all other proteins, although amount band 3 slightly reduced 6 (G3PD) elevated. spectrin content these cells normal, as measured both radioimmunoassay. Erythrocytes from patient's biologic parents were hematologically 4.2. Immunological analysis using affinity purified antibodies that composed equal 74-kD 72-kD doublet, whereas primarily monomer. Proteolytic digestion studies trypsin, alpha-chymotrypsin papain demonstrated similar but not identical to protein. Binding showed membranes bound same extent membranes, suggesting binding site(s) for normal. Depleting actin resulted in loss nearly two-thirds ankyrin, depletion no ankyrin. Repletion before spectrin-actin extraction partially prevented These results suggest may function stabilize ankyrin on membrane.