Defective anion transport activity of the abnormal band 3 in hereditary ovalocytic red blood cells

Schofield, Ann E.; Reardon, David M.; Tanner, Michael

doi:10.1038/355836a0

Cited by 157 publications

(131 citation statements)

References 17 publications

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“…cDNAs and Mutagenesis-cDNAs encoding human kAE1 (27,34), human eAE1 SAO (Southeast Asian Ovalocytosis) (11,35), and mouse eAE1 E699Q (36) were previously described. cDNAs encoding human CA2 (gift of W. Sly, St. Louis University, St. Louis, MO) and the CA2 mutants V143Y (37) (gift of C. Fierke, University of Michigan, Ann Arbor, MI) and ⌬ N 17/C206S cDNA (38) (gift of U. Carlsson, University of Linkoping, Linkoping, Sweden) were subcloned into the oocyte expression vector pXT7.…”

Section: Methodsmentioning

confidence: 99%

“…The heterozygous hAE1 mutant SAO (AE1 ⌬400 -408) is associated with Southeast Asian ovalocytosis, and contributes to dRTA as a compound heterozygous mutation (10). AE1 SAO transports neither sulfate in erythrocytes (35) nor Cl Ϫ in oocytes (42,43). The engineered mAE1 mutant E699Q cannot mediate Cl Ϫ /Cl Ϫ exchange, despite its enhanced exchange of extracellular sulfate for either intracellular sulfate or Cl Ϫ (36).…”

Section: Functional Effects Of Sequential Truncation Of the Kae1 C-mentioning

confidence: 99%

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Deficient HCO3- Transport in an AE1 Mutant with Normal Cl- Transport Can be Rescued by Carbonic Anhydrase II Presented on an Adjacent AE1 Protomer

Dahl¹,

Jiang

Chernova

et al. 2003

Journal of Biological Chemistry

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؊ exchange by an AE1 missense mutant devoid of CA2 binding, with activity further enhanced by CA2 co-expression. The same transport-incompetent AE1 mutants failed to rescue Cl ؊ /HCO 3 ؊ exchange by the AE1 truncation mutant 896X, despite preservation of the latter's core CA2 binding site. These data increase the minimal extent of a functionally defined CA2 binding site in AE1. The inter-protomeric rescue of HCO 3 ؊ transport within the AE1 dimer shows functional proximity of the C-terminal cytoplasmic tail of one protomer to the anion translocation pathway in the adjacent protomer within the AE1 heterodimer. The data strongly support the hypothesis that an intact transbilayer anion translocation pathway is completely contained within an AE1 monomer.

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Section: Methodsmentioning

confidence: 99%

Section: Functional Effects Of Sequential Truncation Of the Kae1 C-mentioning

confidence: 99%

Deficient HCO3- Transport in an AE1 Mutant with Normal Cl- Transport Can be Rescued by Carbonic Anhydrase II Presented on an Adjacent AE1 Protomer

Dahl¹,

Jiang

Chernova

et al. 2003

Journal of Biological Chemistry

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“…It is experimentally clarified that the biophysical consequences of this mutation are a marked decrease in lateral mobility of band 3 in the membrane, and an increase in membrane extensional rigidity (Mohandas et al, 1992). And it is also shown that the protein having nine amino acids deletion is defective in anion transport activity (Schofield et al, 1992a).…”

mentioning

confidence: 99%

Twenty seven nucleotide deletion within exon 11 of the erythrocyte band 3 gene in Indonesian ovalocytosis

et al. 1994

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“…All transport measurements were performed within the linear range of the assay. The [ 35 S]sulfate influx into red cells was measured using variant and control cells at 10% hematocrit, and the number of DIDS-binding sites was determined by titration of sulfate transport as described previously (25). The V max and apparent K m for [ 35 S]sulfate influx were calculated from sulfate influx measurements in the absence of DIDS using sulfate concentrations between 0.4 and 50 mM.…”

Section: Methodsmentioning

confidence: 99%

Altered Structure and Anion Transport Properties of Band 3 (AE1, SLC4A1) in Human Red Cells Lacking Glycophorin A

Bruce

Pan

Cope

et al. 2004

Journal of Biological Chemistry

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We have studied the properties of band 3 in different glycophorin A (GPA)-deficient red cells. These red cells lack either both GPA and glycophorin B (GPB) (M k M k cells) or GPA (En(a؊) cells) or contain a hybrid of GPA and GPB (MiV cells). Sulfate transport was reduced in all three red cell types to ϳ60% of that in normal control red cells as a result of an increased apparent K m for sulfate. Transport of the monovalent anions iodide and chloride was also reduced. The reduced iodide transport resulted from a reduction in the V max for iodide transport. The anion transport site was investigated by measuring iodide fluorescence quenching of eosin-5-maleimide (EMA)-labeled band 3. The GPA-deficient cells had a normal K d for iodide binding, in agreement with the unchanged K m found in transport studies. However, the apparent diffusion quenching constant (K q ) was increased, and the fluorescence polarization of band 3-bound EMA decreased in the variant cells, suggesting increased flexibility of the protein in the region of the EMA-binding site. This increased flexibility is probably associated with the decrease in V max observed for iodide transport. Our results suggest that band 3 in the red cell can take up two different structures: one with high anion transport activity when GPA is present and one with lower anion transport activity when GPA is absent.The anion exchange protein AE1 (band 3) and glycophorin A (GPA) 1 are both present in the human red cell membrane at ϳ1 ϫ 10 6 copies/cell. Evidence suggests that these two proteins associate both in internal cell membranes during their biosynthesis and in red cell membranes (1-12). Reduction of the amount of band 3 in the human red cell membrane results in membrane defects, and the almost total absence of band 3 in man compromises life and requires intervention (13,14). However, GPA can be reduced or even absent as a result of genetic defects without known clinical consequences (15). In some individuals, GPA is completely absent in the red cell membrane (En(aϪ) cells), whereas other individuals have red cells that lack both GPA and glycophorin B (GPB) (M k M k cells). In other cases, only GPB is absent in the red cell membrane (S Ϫ s Ϫ U Ϫ cells). The GPA and GPB genes are located in tandem on chromosome 4, and these two highly homologous genes are prone to deletions, gene conversions, and crossovers.The structure and function of band 3 are altered in En(aϪ) red cells (16,17) and M k M k red cells (18 -20). In these cells, band 3 has a higher apparent molecular weight due to an increase in the size of the N-glycan chain (16,17,20). In M k M k cells, the sulfate transport activity of band 3 is ϳ60% of that in normal red cells as a result of an increase in the apparent K m for sulfate (20). It has been argued that this altered transport activity is due to the lack of GPA in M k M k cells, as there is no evidence for an interaction between band 3 and GPB.The transport domain of band 3 has been studied by the fluorescence quenching of eosin-5-maleimide (EMA)-labeled...

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Defective anion transport activity of the abnormal band 3 in hereditary ovalocytic red blood cells

Cited by 157 publications

References 17 publications

Deficient HCO3- Transport in an AE1 Mutant with Normal Cl- Transport Can be Rescued by Carbonic Anhydrase II Presented on an Adjacent AE1 Protomer

Deficient HCO3- Transport in an AE1 Mutant with Normal Cl- Transport Can be Rescued by Carbonic Anhydrase II Presented on an Adjacent AE1 Protomer

Twenty seven nucleotide deletion within exon 11 of the erythrocyte band 3 gene in Indonesian ovalocytosis

Altered Structure and Anion Transport Properties of Band 3 (AE1, SLC4A1) in Human Red Cells Lacking Glycophorin A

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