Abnormality in a specific protein of the erythrocyte membrane in hereditary spherocytosis

Complete amino acid sequence and homologies of human erythrocyte membrane protein band 4.2.

“…Binding measurements and competition studies suggest that ankyrin and band 4.2 bind to distinct sites on the cytoplasmic domain of band 3 (4). While we and others have not found any effect of band 4.2 on ankyrin association with erythrocyte membranes (4-6), other studies suggest that band 4.2 may stabilize ankyrin-band 3 associations (7).While the exact function of band 4.2 on the erythrocyte membrane is not known, individuals whose erythrocytes lack or are deficient in band 4.2 have hemolytic anemia associated with spherocytic or elliptocytic erythrocytes (7,8). Absence of band 4.2 associated with spur or target erythrocytes has also been reported (9).…”

“…While the exact function of band 4.2 on the erythrocyte membrane is not known, individuals whose erythrocytes lack or are deficient in band 4.2 have hemolytic anemia associated with spherocytic or elliptocytic erythrocytes (7,8). Absence of band 4.2 associated with spur or target erythrocytes has also been reported (9).…”

Induction of Erythrocyte Protein 4.2 Gene Expression during Differentiation of Murine Erythroleukemia Cells

“…Although the exact function of P4.2 is not defined, several lines of evidence suggest that it plays an important role in maintaining the stability and flexibility of RBCs. First, individuals whose RBCs are severely deficient in P4.2 experience various degrees of hemolytic anemia (Hayashi et al, 1974;Ideguchi et al, 1990;Nozawa et al, 1974;Rybicki et al, 1988;Bouhassira et al, 1992). Second, genetic analysis of patients' DNA and RNA reveals the presence of mutations in the P4.2 gene (Bouhassira et al, 1992;Takaoka et al, 1994;Hayette et al, 1995a,b;Iwamoto et al, 1993;Kanzaki et al, 1995a,b;Matsuda et al, 1995).…”

Electron microscopic evidence of impaired intramembrane particles and instability of the cytoskeletal network in band 4.2 deficiency in human red cells

“…Band 4.2 is one of the major membrane proteins in human red cells and constitutes approximately 5% of total membrane proteins [Korsgren and Cohen, 1986Sung et al, 1992;Cohen et al, 19931. Although the detailed function of this protein is unknown, it has been shown that band 4.2 functionally binds strongly to transmembrane protein band 3 (AE-1) and thereby is assumed to play an important role in maintaining the normal structure and function of the cytoskeleta1 network and intramembrane particles (IMPs) [Cohen and Gascard, 1992;Cohen et al, 19931. Since 1974, when the first two reports of band 4.2 deficiency [Hayashi et al, 1974;Nozawa et al, 19741 appeared independently, approximately 30 cases with this disorder have been described [Rybicki et al, 1988;Ghanem et al, 1990;Ideguchi et al, 1990;Iwamoto et al, 1993;Yawata, 1994a,b;Inoue et al, 1994;Takaoka et al, 1994;Hayette et al, 1995a,b;Kanzaki et al, 1995a,b]. These cases demonstrated uncompensated hemolytic anemia, abnormal red cell morphology of either spherocytosis [Yawata, 1994al or ovalostomatocytosis [Yawata, 1994a1, increased osmotic fragility [Yawata, 1994a,b], increased sodium influx and efflux [Yawata, 1994b;Inoue et al, 19941, increased lateral mobility [Yawata, 1994a;Inoue et al, 19941.…”