Biomaterial Database

Transport activity of AE3 chloride/bicarbonate anion-exchange proteins and their regulation by intracellular pH. 1999

D Sterling, and J R Casey

Department of Physiology, Membrane Transport Group, MRC Group in Molecular Biology of Membranes, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.

Plasma membrane Cl(-)/HCO(3)(-) anion-exchange (AE) proteins contribute to regulation of intracellular pH (pH(i)). We characterized the transport activity and regulation by pH(i) of full-length AE3 and the cardiac isoform, AE3c, both of which are expressed in the heart. AE3c is an N-terminal variant of AE3. We also characterized AE1, AE2 and a deletion construct (AE3tr) coding for the common region of AE3 and AE3c. AE proteins were expressed by transient transfection of HEK-293 cells, and transport activity was monitored by following changes of intracellular pH or intracellular chloride concentration associated with anion exchange. Transport activities, measured as proton flux (mM H(+).min(-1)), were as follows: AE1, 24; AE2, 32; full-length AE3, 9; AE3c, 4 and AE3tr, 4. The wide range of transport activities is not explained by variation of cell surface processing since approx. 30% of each isoform was expressed on the cell surface. pH(i) was clamped at a range of values from 6.0-9.0 to examine regulation of AE proteins by pH(i). Whereas AE2 was steeply inhibited by acid pH(i), AE1, AE3 and AE3c were essentially insensitive to changes of pH(i). We conclude that AE3 and AE3c can contribute to pH(i) recovery after cellular-acid loading.

UI	MeSH Term	Description	Entries
D007424	Intracellular Fluid	The fluid inside CELLS.	Fluid, Intracellular,Fluids, Intracellular,Intracellular Fluids
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
D011994	Recombinant Proteins	Proteins prepared by recombinant DNA technology.	Biosynthetic Protein,Biosynthetic Proteins,DNA Recombinant Proteins,Recombinant Protein,Proteins, Biosynthetic,Proteins, Recombinant DNA,DNA Proteins, Recombinant,Protein, Biosynthetic,Protein, Recombinant,Proteins, DNA Recombinant,Proteins, Recombinant,Recombinant DNA Proteins,Recombinant Proteins, DNA
D002460	Cell Line	Established cell cultures that have the potential to propagate indefinitely.	Cell Lines,Line, Cell,Lines, Cell
D002712	Chlorides	Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.	Chloride,Chloride Ion Level,Ion Level, Chloride,Level, Chloride Ion
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D006863	Hydrogen-Ion Concentration	The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH	pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D001639	Bicarbonates	Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.	Bicarbonate,Bicarbonate Ions,Hydrogen Carbonates,Bicarbonate Ion,Carbonic Acid Ions,Hydrogen Carbonate,Carbonate, Hydrogen,Carbonates, Hydrogen,Ion, Bicarbonate,Ions, Bicarbonate,Ions, Carbonic Acid