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Coexpression of band 3 mutants and Rh polypeptides: differential effects of band 3 on the expression of the Rh complex containing D polypeptide and the Rh complex containing CcEe polypeptide.
- Source :
-
Blood [Blood] 2001 Apr 15; Vol. 97 (8), pp. 2496-505. - Publication Year :
- 2001
-
Abstract
- K562 cells were stably transfected with cDNAs encoding the band 3 found in Southeast Asian ovalocytosis (B3SAO, deletion of residues 400-408), band 3 with a transport-inactivating E681Q point mutation (B3EQ), or normal band 3 (B3). Flow cytometric analysis and quantitative immunoblotting revealed that B3SAO expressed alone was translocated to the plasma membrane, at levels similar to B3 or B3EQ. Nine monoclonal antibodies that reacted with extracellular loops of B3 also reacted with B3SAO, although the affinity of most antibodies for the mutant protein was reduced. Both known Wr(b) epitopes were expressed on K562/B3SAO cells, demonstrating that B3SAO interacts with glycophorin A. The growth rates of K562 clones expressing equivalent amounts of B3 and B3EQ were the same, suggesting that the potentially toxic transport function of band 3 may be regulated in K562 cells. The band 3-mediated enhancement of Rh antigen reactivity and the depression of Rh epitopes on SAO erythrocytes were investigated by comparing the coexpression of B3, B3SAO, or B3EQ in K562 clones expressing exogenous RhcE or RhD polypeptides. The results are consistent with an interaction between band 3 and the Rh polypeptide-Rh glycoprotein (RhAG) complex, which may enhance translocation of the complex or affect its conformation in the plasma membrane. The data suggest that the interaction between band 3 and the RhD-RhAG complex is weaker than it is between band 3 and the RhCcEe-RhAG complex.
- Subjects :
- Anion Exchange Protein 1, Erythrocyte biosynthesis
Anion Exchange Protein 1, Erythrocyte immunology
Anion Exchange Protein 1, Erythrocyte physiology
Antibodies, Monoclonal immunology
Antibody Affinity
Antibody Specificity
Blotting, Western
Cell Division
DNA, Complementary genetics
Epitopes immunology
Gene Expression Profiling
Glycophorins metabolism
Humans
Macromolecular Substances
Membrane Glycoproteins metabolism
Mutagenesis, Site-Directed
Neoplasm Proteins metabolism
Point Mutation
Protein Binding
Protein Conformation
Protein Transport
Recombinant Fusion Proteins physiology
Rh-Hr Blood-Group System genetics
Sequence Deletion
Transfection
Tumor Stem Cell Assay
Anion Exchange Protein 1, Erythrocyte genetics
Blood Proteins
Erythrocyte Membrane metabolism
Gene Expression Regulation, Leukemic
Glycoproteins metabolism
K562 Cells metabolism
Rh-Hr Blood-Group System biosynthesis
Rh-Hr Blood-Group System metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-4971
- Volume :
- 97
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- Blood
- Publication Type :
- Academic Journal
- Accession number :
- 11290615
- Full Text :
- https://doi.org/10.1182/blood.v97.8.2496