The Anion Transport Protein

Jennings, Michael L.

doi:10.1007/978-1-4612-4500-1_8

Cited by 10 publications

(8 citation statements)

References 136 publications

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“…One prevailing model of AE1 suggests that the anion translocation pore forms an outward facing funnel and narrows to a permeability barrier at Glu 681 (47). Our data may provide some support for the model.…”

Section: Discussionsupporting

confidence: 72%

Identification of Residues Lining the Translocation Pore of Human AE1, Plasma Membrane Anion Exchange Protein

Tang

Kovács

Sterling

et al. 1999

Journal of Biological Chemistry

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AE1 is the chloride/bicarbonate anion exchanger of the erythrocyte plasma membrane. We have used scanning cysteine mutagenesis and sulfhydryl-specific chemistry to identify pore-lining residues in the Ser 643 -Ser 690 region of the protein. The Ser 643 -Ser 690 region spans transmembrane segment 8 of AE1 and surrounds Glu 681 , which may reside at the transmembrane permeability barrier. Glu 681 also directly interacts with some anions during anion transport. The introduced cysteine mutants were expressed by transient transfection of HEK293 cells. Anion exchange activity was assessed by measurement of changes of intracellular pH, which follow transmembrane bicarbonate movement mediated by AE1. To identify residues that might form part of an aqueous transmembrane pore, we measured anion exchange activity of each introduced cysteine mutant before and after incubation with the sulfhydryl reagents para-chloromercuribenzene sulfonate and 2-(aminoethyl)methanethiosulfonate hydrobromide. Our data identified transmembrane mutants A666C, S667C, L669C, L673C, L677C, and L680C and intracellular mutants I684C and I688C that could be inhibited by sulfhydryl reagents and may therefore form a part of a transmembrane pore. These residues map to one face of a helical wheel plot. The ability to inhibit two intracellular mutants suggests that transmembrane helix 8 extends at least two helical turns beyond the intracellular membrane surface. The identified hydrophobic pore-lining residues (leucine, isoleucine, and alanine) may limit interactions with substrate anions.

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Section: Discussionsupporting

confidence: 72%

Identification of Residues Lining the Translocation Pore of Human AE1, Plasma Membrane Anion Exchange Protein

Tang

Kovács

Sterling

et al. 1999

Journal of Biological Chemistry

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“…Knauf, 1989;Jennings, 1992a;Jennings, 1992b;Knauf et al, 2002). The characterisation of the kinetics of anion transport in other RBC species is very incomplete.…”

Section: Chloride Permeabilitymentioning

confidence: 99%

The permeability of red blood cells to chloride, urea, and water

Brahm

2013

Journal of Experimental Biology

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SUMMARYThis study extends permeability (P) data on chloride, urea and water in red blood cells (RBC), and concludes that the urea transporter (UT-B) does not transport water. cms -1 (human). DIDS, DNDS and phloretin inhibit P Cl by >99% in all RBC species. PCMBS, PCMB and phloretin inhibit P urea by >99% in Amphiuma, dog and human RBC, but not in chick and duck RBC. PCMBS and PCMB inhibit P d in duck, dog and human RBC, but not in chick and Amphiuma RBC. Temperature dependence, as measured by apparent activation energy, E A , of P Cl is 117.8 (duck), 74.9 (Amphiuma) and 89.6kJmol −1 (dog). The E A of P urea is 69.6 (duck) and 53.3kJmol −1 (Amphiuma), and that of P d is 34.9 (duck) and 32.1kJmol −1 (Amphiuma). The present and previous RBC studies indicate that anion (AE1), urea (UT-B) and water (AQP1) transporters only transport chloride (all species), water (duck, dog, human) and urea (Amphiuma, dog, human), respectively. Water does not share UT-B with urea, and the solute transport is not coupled under physiological conditions.

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“…AE proteins seem to be involved in intracellular pH and cell-volume regulation, as well as transepithelial acid/base transport Mason et al 1989;Jennings 1992;Alper 1994). These proteins are encoded by a family of genes, three of which (AE1, AE2, and AE3) are well characterized (reviewed by Kopito 1990;Alper 1994).…”

Section: Introductionmentioning

confidence: 99%

In situ detection of AE2 anion-exchanger mRNA in the human liver

García

Montuenga

Medina

et al. 1998

Cell and Tissue Research

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Na + -independent anion exchangers, a family of membrane proteins that mediate electroneutral exchanges of chloride and bicarbonate ions across the cell membrane, are considered to be involved in intracellular pH regulation as well as in transepithelial acid/base transport. Previous immunohistochemical data have shown that anion-exchanger-2 (AE2) protein is expressed in the liver parenchyma, localizing at both the canaliculi and the luminal surfaces of intrahepatic bile ducts, where it may have a role in the biliary secretion of bicarbonate. In the present study, we have carried out in situ hybridization experiments on biopsies of human liver using three overlapping antisense anion-exchanger-2 riboprobes. Anion-exchanger-2 mRNA signals were localized mainly in the cytoplasm of terminal and interlobular bile-duct cells, whereas weaker signals were observed in bile-duct cells of larger intrahepatic ducts. Furthermore, some hepatocytes, mostly periportal, contained detectable anion-exchanger-2 mRNA signals in their cytoplasm. No hybridization signals were observed in controls with sense riboprobes, with omission of the antisense probe, or with treatment of the sections with RNase before hybridizations. Finally, intense anion-exchanger-2 hybridization signals were observed in lymphomononuclear cells in sinusoids and in portal infiltrates. Immunocytochemical data from reverse-phase sections suggest that these cells correspond to some of the CD45R+ (UCHL1+) T lymphocytes resident in the liver.

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The Anion Transport Protein

Cited by 10 publications

References 136 publications

Identification of Residues Lining the Translocation Pore of Human AE1, Plasma Membrane Anion Exchange Protein

Identification of Residues Lining the Translocation Pore of Human AE1, Plasma Membrane Anion Exchange Protein

The permeability of red blood cells to chloride, urea, and water

In situ detection of AE2 anion-exchanger mRNA in the human liver

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