Biomaterial Database

Mechanism of anion exchange across the red cell membrane by band 3: interactions between stilbenedisulfonate and NAP-taurine binding sites. 1981

I G Macara, and L C Cantley

Anion exchange across the erythrocyte membrane can be inhibited competitively by stilbenedisulfonates, which bind to the external transport of the band 3 protein, and noncompetitively by external NAP-taurine [2-[N-(4-azido-2-nitrophenyl)amino]ethanesulfonate], which it has been suggested binds to a "modifier site" [Knauf, P. A., Ship. S., Breur, W., MCCulloch, L., & Rothstein, A. (1978) J. Gen. Physiol. 72, 604-630]. The binding of the two types of inhibitor of erythrocyte membranes is shown in the present study to be competitive, indicating that binding to the same subunit of band 3 is mutually exclusive. Covalent labeling of red cells with a stilbenedisulfonate [4-benzamido-4'-isothiocyano-stilbene-2,2'-disulfonate (BIDS)] to 80% saturation had no detectable effect upon the Ki for inhibition of [32P]phosphate influx by NAP-taurine, indicating that when bound to adjacent subunits in the band 3 dimer, the two types of inhibitor do not interact. In addition to the external NAP-taurine site, a second high-affinity NAP-taurine site (Kd = 15 microM) was detected on the cytoplasmic side of red cell membranes. This site is less than 51 A from the disulfonic stilbene binding site, as judged by fluorescence resonance energy transfer from BIDS to NAP-taurine. Binding at this site is not affected by covalent attachment of BIDS, and no clear role for this site in transport could be determined. On the basis of these studies we present a model indicating that disulfonic stilbenes bind to a site which overlaps both the anion transport site and the modifier site on a band 3 monomer and suggests that the modifier site may be part of a transporting gate.

UI	MeSH Term	Description	Entries
D008565	Membrane Proteins	Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.	Cell Membrane Protein,Cell Membrane Proteins,Cell Surface Protein,Cell Surface Proteins,Integral Membrane Proteins,Membrane-Associated Protein,Surface Protein,Surface Proteins,Integral Membrane Protein,Membrane Protein,Membrane-Associated Proteins,Membrane Associated Protein,Membrane Associated Proteins,Membrane Protein, Cell,Membrane Protein, Integral,Membrane Proteins, Integral,Protein, Cell Membrane,Protein, Cell Surface,Protein, Integral Membrane,Protein, Membrane,Protein, Membrane-Associated,Protein, Surface,Proteins, Cell Membrane,Proteins, Cell Surface,Proteins, Integral Membrane,Proteins, Membrane,Proteins, Membrane-Associated,Proteins, Surface,Surface Protein, Cell
D008956	Models, Chemical	Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Chemical Models,Chemical Model,Model, Chemical
D001798	Blood Proteins	Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.	Blood Protein,Plasma Protein,Plasma Proteins,Serum Protein,Serum Proteins,Protein, Blood,Protein, Plasma,Protein, Serum,Proteins, Blood,Proteins, Plasma,Proteins, Serum
D004910	Erythrocyte Membrane	The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.	Erythrocyte Ghost,Red Cell Cytoskeleton,Red Cell Ghost,Erythrocyte Cytoskeleton,Cytoskeleton, Erythrocyte,Cytoskeleton, Red Cell,Erythrocyte Cytoskeletons,Erythrocyte Ghosts,Erythrocyte Membranes,Ghost, Erythrocyte,Ghost, Red Cell,Membrane, Erythrocyte,Red Cell Cytoskeletons,Red Cell Ghosts
D004912	Erythrocytes	Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.	Blood Cells, Red,Blood Corpuscles, Red,Red Blood Cells,Red Blood Corpuscles,Blood Cell, Red,Blood Corpuscle, Red,Erythrocyte,Red Blood Cell,Red Blood Corpuscle
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001457	Anion Exchange Protein 1, Erythrocyte	A major integral transmembrane protein of the ERYTHROCYTE MEMBRANE. It is the anion exchanger responsible for electroneutral transporting in CHLORIDE IONS in exchange of BICARBONATE IONS allowing CO2 uptake and transport from tissues to lungs by the red blood cells. Genetic mutations that result in a loss of the protein function have been associated with type 4 HEREDITARY SPHEROCYTOSIS.	Anion Transport Protein, Erythrocyte,Band 3 Protein,Erythrocyte Anion Transport Protein,Erythrocyte Membrane Band 3 Protein,AE1 Anion Exchanger,AE1 Chloride-Bicarbonate Exchanger,AE1 Cl- HCO3- Exchanger,AE1 Gene Product,Anion Exchanger 1,Antigens, CD233,Band 3 Anion Transport Protein,Band III Protein,CD233 Antigen,CD233 Antigens,Capnophorin,EPB3 Protein,Erythrocyte Anion Exchanger,Erythrocyte Membrane Anion Transport Protein,Erythrocyte Membrane Protein Band 3, Diego Blood Group,Protein Band 3,SLC4A1 Protein,Solute Carrier Family 4 Member 1,Solute Carrier Family 4, Anion Exchanger, Member 1,AE1 Chloride Bicarbonate Exchanger,AE1 Cl HCO3 Exchanger,Anion Exchanger, Erythrocyte,Antigen, CD233,Chloride-Bicarbonate Exchanger, AE1,Exchanger 1, Anion,Protein, EPB3
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill