Bicarbonate uptake via an anion exchange protein is the main mechanism of inorganic carbon acquisition by the giant kelpMacrocystis pyrifera(Laminariales, Phaeophyceae) under variable pH

2014 ◽  
Vol 50 (6) ◽  
pp. 998-1008 ◽  
Author(s):  
Pamela A. Fernández ◽  
Catriona L. Hurd ◽  
Michael Y. Roleda
Keyword(s):  
Anion Exchange ◽  
Inorganic Carbon ◽  
Main Mechanism ◽  
Anion Exchange Protein ◽  
Bicarbonate Uptake ◽  
Exchange Protein ◽  
Inorganic Carbon Acquisition

scholarly journals External α-carbonic anhydrase and solute carrier 4 are required for bicarbonate uptake in a freshwater angiosperm

2020 ◽  
Vol 71 (19) ◽  
pp. 6004-6014
Author(s):  
Wenmin Huang ◽  
Shijuan Han ◽  
Hongsheng Jiang ◽  
Shuping Gu ◽  
Wei Li ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Anion Exchange ◽  
Inorganic Carbon ◽  
Carbon Uptake ◽  
Co2 Uptake ◽  
Co2 Concentrations ◽  
Anion Exchange Protein ◽  
Solute Carrier ◽  
Inorganic Carbon Uptake ◽  
Exchange Protein

Abstract The freshwater monocot Ottelia alismoides is the only known species to operate three CO2-concentrating mechanisms (CCMs): constitutive bicarbonate (HCO3–) use, C4 photosynthesis, and facultative Crassulacean acid metabolism, but the mechanism of HCO3– use is unknown. We found that the inhibitor of an anion exchange protein, 4,4'-diisothio-cyanatostilbene-2,2'-disulfonate (DIDS), prevented HCO3– use but also had a small effect on CO2 uptake. An inhibitor of external carbonic anhydrase (CA), acetazolamide (AZ), reduced the affinity for CO2 uptake but also prevented HCO3– use via an effect on the anion exchange protein. Analysis of mRNA transcripts identified a homologue of solute carrier 4 (SLC4) responsible for HCO3– transport, likely to be the target of DIDS, and a periplasmic α-carbonic anhydrase 1 (α-CA1). A model to quantify the contribution of the three different pathways involved in inorganic carbon uptake showed that passive CO2 diffusion dominates inorganic carbon uptake at high CO2 concentrations. However, as CO2 concentrations fall, two other pathways become predominant: conversion of HCO3– to CO2 at the plasmalemma by α-CA1 and transport of HCO3– across the plasmalemma by SLC4. These mechanisms allow access to a much larger proportion of the inorganic carbon pool and continued photosynthesis during periods of strong carbon depletion in productive ecosystems.

Anion exchange protein (band 3) in human erythrocytes characterized by different abnormalities

1993 ◽  
Vol 220 (2) ◽  
pp. 211-217 ◽  
Author(s):  
A. Giuliani ◽  
S. Marini ◽  
L. Ferroni ◽  
S.G. Condo' ◽  
M.T. Ramacci ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Protein Band ◽  
Band 3 ◽  
Human Erythrocytes ◽  
Anion Exchange Protein ◽  
Exchange Protein

Oxidative stress activates anion exchange protein 2 and AP-1 in airway epithelial cells

2002 ◽  
Vol 283 (4) ◽  
pp. L791-L798 ◽  
Author(s):  
Jennifer L. Turi ◽  
Ilona Jaspers ◽  
Lisa A. Dailey ◽  
Michael C. Madden ◽  
Luisa E. Brighton ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Epithelial Cells ◽  
Protein Expression ◽  
Anion Exchange ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Anion Exchange Protein ◽  
Mrna And Protein Expression ◽  
Exchange Protein

Anion exchange protein 2 (AE2) is a membrane-bound protein that mediates chloride-bicarbonate exchange. In addition to regulating intracellular pH and cell volume, AE2 exports superoxide (O[Formula: see text]·) to the extracellular matrix in an HCO[Formula: see text]-dependent process. Given this ability to export O[Formula: see text]·, we hypothesized that expression of AE2 in the lung is regulated by oxidative stress. AE2 mRNA and protein expression was measured by RT-PCR and Western blot analysis, respectively, in differentiated human bronchial epithelial cells exposed to H2O2 (100 μM). Alterations in in vivo AE2 protein expression were evaluated in lung tissue of rats exposed to 70% O2. The role of transcription factor activator protein (AP)-1 in oxidant regulation of AE2 was evaluated by EMSA and by immunoblotting of nuclear phospho-c- jun. Results show increased AE2 mRNA and protein expression after oxidant exposure. This was preceded by transient increases in DNA binding of AE2-specific AP-1 and phosphorylation of c- jun. This study demonstrates that AE2 expression is regulated by oxidative stress in airway epithelial cells and that this regulation correlates with activation of AP-1.

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