Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
J Gen Physiol
1997 Mar 01;1093:345-60. doi: 10.1085/jgp.109.3.345.
Show Gene links
Show Anatomy links
Electrogenic sulfate/chloride exchange in Xenopus oocytes mediated by murine AE1 E699Q.
Chernova MN, Jiang L, Crest M, Hand M, Vandorpe DH, Strange K, Alper SL.
???displayArticle.abstract???
Functional evaluation of chemically modified human erythrocytes has led to the proposal that amino acid residue E681 of the band 3 anion exchanger AE1 lies on the anion translocation pathway and is a proton carrier required for H+/SO4(2-) cotransport. We have tested in Xenopus oocytes the functional consequences of mutations in the corresponding residue E699 of mouse AE1. Most mutations tested abolished AE1-mediated Cl- influx and efflux. Only the E699Q mutation increased stilbene disulfonate-sensitive efflux and influx of SO4(2-). E699Q-mediated Cl- influx was activated by elevation of intracellular SO4(2-), but E699Q-mediated Cl- efflux was undetectable. The DNDS (4,4'-dinitrostilbene-2,2'-disulfonic acid) sensitivity of E699Q-mediated SO4(2-) efflux was indistinguishable from that of wt AE1-mediated Cl- efflux. The extracellular anion selectivity of E699Q-mediated SO4(2-) efflux was similar to that of wt AE1-mediated Cl- efflux. The stoichiometry of E699Q-mediated exchange of extracellular Cl- with intracellular SO4(2-) was 1:1. Whereas SO4(2-) injection into oocytes expressing wt AE1 produced little change in membrane potential or resistance, injection of SO4(2-), but not of Cl- or gluconate, into oocytes expression E699Q depolarized the membrane by 17 mV and decreased membrane resistance by 66%. Replacement of bath Cl- with isethionate caused a 28-mV hyperpolarization in SO4(2-)-loaded oocytes expressing E699Q, but had no effect on oocytes expressing wt AE1. Extracellular Cl(-)-dependent depolarization of SO4(2-)-preloaded oocytes was blocked by DNDS. AE1 E699Q-mediated inward current measured in the presence of extracellular Cl- was of magnitude sufficient to account for measured 35SO4(2-) efflux. Thus, AE1 E699Q-mediated SO4(2-)/Cl- exchange operated largely, if not exclusively, as an electrogenic, asymmetric, 1:1 anion exchange. The data confirm the proposal that E699 resides on or contributes to the integrity of the anion translocation pathway of AE1. A single amino acid change in the sequence of AE1 converted electroneutral to electrogenic anion exchange without alteration of SO4(2-)/Cl- exchange stoichiometry.
???displayArticle.pubmedLink???
9089441 ???displayArticle.pmcLink???PMC2217076 ???displayArticle.link???J Gen Physiol ???displayArticle.grants???[+]
Figure 2. SO42− efflux by mutant AE1 polypeptides. (A) Extracellular SO42− supported 35SO42− efflux from AE1 E699Q-expressing oocytes (lower two traces) but not from oocytes expressing wt AE1 or AE1 mutants with T, K, G, or R in place of E699 (upper cluster of 8 traces). Extracellular condition shown above x axis. DIDS was added in the continued presence of SO42−. Representative of 3 similar experiments performed 4–5 d after cRNA injection. Each trace represents a single oocyte. (B) SO42−/Cl− exchange mediated by AE1 E699Q was 70% faster than SO42−/SO42− exchange. DIDS inhibited efflux in the continued presence of Cl−. The two uppermost traces show efflux from water-injected oocytes. The six traces below show efflux from AE1 E699Q-expressing oocytes. (C) Bar graph of the data in B, (n) for each condition above bars. *P < 0.02.
Figure 3. Biosynthesis and cell surface expression of AE1 E699Q and wt AE1. 72 h after cRNA injection, metabolically labelled oocytes expressing wt AE1 (lanes 1 and 2), AE1 E699Q (lanes 3 and 4), or no cRNA (lane 5, water-injected) were incubated for 3 h in the absence (lanes 1, 3, and 5) or presence (lanes 2 and 4) of 5 mg/ml chymotrypsin as described in methods. Triton X100 extracts of the oocytes were subjected to immunoprecipitation with anti-AE1 antibody, SDS-PAGE, and autoradiography. Arrows indicate holoprotein and the 60-kD NH2-terminal chymotryptic fragment of AE1 (p60). Representative of four similar experiments.
Figure 4. DNDS inhibits anion exchange by wt AE1 and by E699Q AE1 with similar potency. (A) Effect of increasing concentrations of DNDS on AE1 E699Q-mediated 35SO42− efflux into Cl− medium. Blockade was reversible. Each trace represents an individual oocyte. Upper trace is water-injected oocyte. (B) DNDS inhibition dose-response curves of wt AE1-mediated 36Cl− efflux and of AE1 E699Q-mediated 35SO42− efflux. Each of 5 oocytes was exposed for 9 or 12 min to incrementally increasing DNDS concentrations.
Figure 5. (A) Extracellular halide dependence of AE1 E699Q-mediated SO42− efflux. Each line represents a single oocyte. (B) Extracellular anion dependence of AE1 E699Q-mediated 35SO42− efflux. Summary of three similar experiments, with number oocytes evaluated in each condition noted above columns. Relative efflux into iodide medium lacking gluconate salts of Mg2+, Ca2+, and K+ was further reduced to 0.09 ± 0.03 (n = 5), but omission of these gluconate salts did not change values for other anions (not shown).
Figure 6. Experimental format for measurement of stoichiometry of influx vs. efflux. (A) 36Cl− influx into acutely SO42−-loaded or native oocytes injected 13 d earlier with water or with AE1 E699Q cRNA (*P < 0.01). Representative of five similar, paired experiments. AE1 E699Q-mediated 36Cl− influx was measurable in native oocytes from 8 of 10 frogs tested. Influx was measurable in SO42−-loaded oocytes from 9 of 10 frogs tested. (B) Oocytes from the frog of panel A injected 13 d earlier with water (upper trace) or with cRNA (seven lower traces) were acutely injected with 35SO42− to a final intracellular [SO42−] of ∼14 mM, then subjected to the efflux assay. Note that fractional efflux into Cl− medium was less than observed in Fig. 2 B, in which intracellular [SO42−] was ∼1 mM.
Figure 7. Intracellular anion dependence of electrogenic anion exchange. (A) Oocytes injected 72 h previously with cRNA encoding AE1 E699Q were acutely injected (arrow) with 50 nl of 87 mM K salts of SO42−, Cl−, or gluconate as indicated while membrane potential and resistance were recorded. Regular spaced vertical displacements in potential are in response to 10-nA current pulses. (B) An oocyte injected 72 h previously with cRNA encoding wt AE1 was injected with 50 nl 87 mM K2SO4. (C) A water-injected oocyte was injected with 50 nl 87 mM K2SO4.
Figure 8. Membrane potential changes in Na2SO4-loaded oocytes in response to varied extracellular conditions. (A) Membrane potential of a Na2SO4-loaded E699Q-expressing oocyte during two sequential transitions from extracellular Cl− to isethio-nate. (B) Membrane potential of a Na2SO4-loaded E699Q-expressing oocyte in extracellular Cl− medium during introduction and removal of DNDS. (C) Membrane potential of a Na2SO4-loaded wt AE1-expressing oocyte during transition from extracellular Cl− to isethionate. (D) Membrane potential of a Na2SO4-loaded oocyte, previously injected with water, during transition from extracellular Cl− to isethionate. Gaps in the voltage records represent application of stepped voltage protocols (see Fig. 9).
Figure 9. AE1 E699Q-associated currents. (A) Mean I-V curves and representative current traces from Na2SO4-loaded oocytes in extracellular Cl− medium expressing wt AE1 (filled squares, n = 20 oocytes from 6 frogs) and AE1 E699Q (filled circles, n = 54 oocytes from 8 frogs). *P < 0.04; NS, P > 0.05. (B) Comparison of E699Q-mediated currents in Na2SO4-loaded oocytes in the presence of extracellular Cl− (filled circles), extracellular isethionate (open squares, n = 44 oocytes from 7 frogs), and extracellular sulfate (open triangles, n = 5 oocytes from 1 frog). *P < 0.002. (C) Comparison of E699Q-mediated currents in Na2SO4-loaded oocytes in extracellular chloride in the absence (filled circles) and presence of 200 μM DNDS (open diamonds, n = 24 oocytes from 4 frogs) *P < 0.03. Voltage was stepped from a holding potential of −50 mV to test potentials between −80 and +60 mV in 20-mV increments. At potentials ≥+80 mV, endogenous outward currents were activated in all groups of oocytes. Data recorded in extracellular chloride from AE1 E699Q-expressing oocytes is replicated in all three panels.
Alper,
Subtypes of intercalated cells in rat kidney collecting duct defined by antibodies against erythroid band 3 and renal vacuolar H+-ATPase.
1989, Pubmed
Alper,
Subtypes of intercalated cells in rat kidney collecting duct defined by antibodies against erythroid band 3 and renal vacuolar H+-ATPase.
1989,
Pubmed Bar-Noy,
Transport domain of the erythrocyte anion exchange protein.
1990,
Pubmed Bartel,
Anion transport in oocytes of Xenopus laevis induced by expression of mouse erythroid band 3 protein--encoding cRNA and of a cRNA derivative obtained by site-directed mutagenesis at the stilbene disulfonate binding site.
1989,
Pubmed
,
Xenbase Berghout,
The effects of dansylation on the pH dependence of SO4(2-) and Cl- equilibrium exchange and on the H+/SO4(2-) cotransport across the red blood cell membrane.
1989,
Pubmed Bissig,
Functional expression cloning of the canalicular sulfate transport system of rat hepatocytes.
1994,
Pubmed
,
Xenbase Brosius,
The major kidney band 3 gene transcript predicts an amino-terminal truncated band 3 polypeptide.
1989,
Pubmed
,
Xenbase Bruce,
Band 3 HT, a human red-cell variant associated with acanthocytosis and increased anion transport, carries the mutation Pro-868-->Leu in the membrane domain of band 3.
1993,
Pubmed Chernova,
Overexpression of AE1 Prague, but not of AE1 SAO, inhibits wild-type AE1 trafficking in Xenopus oocytes.
1995,
Pubmed
,
Xenbase Costa,
Determination of ionic permeability coefficients of the plasma membrane of Xenopus laevis oocytes under voltage clamp.
1989,
Pubmed
,
Xenbase Fiévet,
Expression of band 3 anion exchanger induces chloride current and taurine transport: structure-function analysis.
1995,
Pubmed
,
Xenbase Fröhlich,
The "tunneling" mode of biological carrier-mediated transport.
1988,
Pubmed Garcia,
Lysine 539 of human band 3 is not essential for ion transport or inhibition by stilbene disulfonates.
1989,
Pubmed
,
Xenbase Groves,
The effects of glycophorin A on the expression of the human red cell anion transporter (band 3) in Xenopus oocytes.
1994,
Pubmed
,
Xenbase Grygorczyk,
Potential dependence of the "electrically silent" anion exchange across the plasma membrane of Xenopus oocytes mediated by the band-3 protein of mouse red blood cells.
1987,
Pubmed
,
Xenbase Hanke-Baier,
Comparison of murine band 3 protein-mediated Cl- transport as measured in mouse red blood cells and in oocytes of Xenopus laevis.
1988,
Pubmed
,
Xenbase Hästbacka,
The diastrophic dysplasia gene encodes a novel sulfate transporter: positional cloning by fine-structure linkage disequilibrium mapping.
1994,
Pubmed Höglund,
Mutations of the Down-regulated in adenoma (DRA) gene cause congenital chloride diarrhoea.
1996,
Pubmed Humphreys,
Functional characterization and regulation by pH of murine AE2 anion exchanger expressed in Xenopus oocytes.
1994,
Pubmed
,
Xenbase Humphreys,
Hypertonic activation of AE2 anion exchanger in Xenopus oocytes via NHE-mediated intracellular alkalinization.
1995,
Pubmed
,
Xenbase Izuhara,
Conformational change of band 3 protein induced by diethyl pyrocarbonate modification in human erythrocyte ghosts.
1989,
Pubmed Jaisser,
Mechanisms of urinary K+ and H+ excretion: primary structure and functional expression of a novel H,K-ATPase.
1993,
Pubmed
,
Xenbase Jarolim,
Duplication of 10 nucleotides in the erythroid band 3 (AE1) gene in a kindred with hereditary spherocytosis and band 3 protein deficiency (band 3PRAGUE).
1994,
Pubmed Jennings,
Effects of membrane potential on electrically silent transport. Potential-independent translocation and asymmetric potential-dependent substrate binding to the red blood cell anion exchange protein.
1990,
Pubmed Jennings,
Modification of a carboxyl group that appears to cross the permeability barrier in the red blood cell anion transporter.
1988,
Pubmed Jennings,
Rapid electrogenic sulfate-chloride exchange mediated by chemically modified band 3 in human erythrocytes.
1995,
Pubmed Jennings,
Anion-proton cotransport through the human red blood cell band 3 protein. Role of glutamate 681.
1992,
Pubmed Jennings,
Reductive methylation of the two 4,4'-diisothiocyanodihydrostilbene-2,2'-disulfonate-binding lysine residues of band 3, the human erythrocyte anion transport protein.
1982,
Pubmed Jennings,
Chemical modification and labeling of glutamate residues at the stilbenedisulfonate site of human red blood cell band 3 protein.
1987,
Pubmed Julien,
Studies on inactivation of anion transport in human red blood cell membrane by reversibly and irreversibly acting arginine-specific reagents.
1988,
Pubmed Kietz,
pH-dependence of inhibition by H2DIDS of mouse erythroid band 3-mediated Cl- transport in Xenopus oocytes. The effect of oligonucleotide-directed replacement of Lys-558 by an Asn residue.
1991,
Pubmed
,
Xenbase Kopito,
Primary structure and transmembrane orientation of the murine anion exchange protein.
,
Pubmed Kunkel,
Efficient site-directed mutagenesis using uracil-containing DNA.
1991,
Pubmed Lepke,
Inverse effects of dansylation of red blood cell membrane on band 3 protein-mediated transport of sulphate and chloride.
1982,
Pubmed Milanick,
Proton-sulfate cotransport: external proton activation of sulfate influx into human red blood cells.
1984,
Pubmed Milanick,
Proton-sulfate co-transport: mechanism of H+ and sulfate addition to the chloride transporter of human red blood cells.
1982,
Pubmed Müller-Berger,
Roles of histidine 752 and glutamate 699 in the pH dependence of mouse band 3 protein-mediated anion transport.
1995,
Pubmed
,
Xenbase Müller-Berger,
Inhibition of mouse erythroid band 3-mediated chloride transport by site-directed mutagenesis of histidine residues and its reversal by second site mutation of Lys 558, the locus of covalent H2DIDS binding.
1995,
Pubmed
,
Xenbase Musch,
Oligomeric forms of skate erythrocyte band 3. Effect of volume expansion.
1994,
Pubmed Passow,
Molecular aspects of band 3 protein-mediated anion transport across the red blood cell membrane.
1986,
Pubmed Sekler,
A conserved glutamate is responsible for ion selectivity and pH dependence of the mammalian anion exchangers AE1 and AE2.
1995,
Pubmed Silberg,
The Down regulated in Adenoma (dra) gene encodes an intestine-specific membrane sulfate transport protein.
1995,
Pubmed
,
Xenbase Tanner,
Molecular and cellular biology of the erythrocyte anion exchanger (AE1).
1993,
Pubmed Thomas,
Intracellular pH measurements in Ehrlich ascites tumor cells utilizing spectroscopic probes generated in situ.
1979,
Pubmed Wieth,
Chloride--bicarbonate exchange in red blood cells: physiology of transport and chemical modification of binding sites.
1982,
Pubmed Wood,
Role of Lys 558 and Lys 869 in substrate and inhibitor binding to the murine band 3 protein: a study of the effects of site-directed mutagenesis of the band 3 protein expressed in the oocytes of Xenopus laevis.
1992,
Pubmed
,
Xenbase
