PMID- 22076132
OWN - NLM
STAT- MEDLINE
DCOM- 20120315
LR  - 20211021
IS  - 1932-6203 (Electronic)
IS  - 1932-6203 (Linking)
VI  - 6
IP  - 11
DP  - 2011
TI  - Transport activity of the sodium bicarbonate cotransporter NBCe1 is enhanced by 
      different isoforms of carbonic anhydrase.
PG  - e27167
LID - 10.1371/journal.pone.0027167 [doi]
LID - e27167
AB  - Transport metabolons have been discussed between carbonic anhydrase II (CAII) and 
      several membrane transporters. We have now studied different CA isoforms, 
      expressed in Xenopus oocytes alone and together with the electrogenic sodium 
      bicarbonate cotransporter 1 (NBCe1), to determine their catalytic activity and 
      their ability to enhance NBCe1 transport activity. pH measurements in intact 
      oocytes indicated similar activity of CAI, CAII and CAIII, while in vitro CAIII 
      had no measurable activity and CAI only 30% of the activity of CAII. All three CA 
      isoforms increased transport activity of NBCe1, as measured by the transport 
      current and the rate of intracellular sodium rise in oocytes. Two CAII mutants, 
      altered in their intramolecular proton pathway, CAII-H64A and CAII-Y7F, showed 
      significant catalytic activity and also enhanced NBCe1 transport activity. The 
      effect of CAI, CAII, and CAII mutants on NBCe1 activity could be reversed by 
      blocking CA activity with ethoxyzolamide (EZA, 10 microM), while the effect of the 
      less EZA-sensitive CAIII was not reversed. Our results indicate that different CA 
      isoforms and mutants, even if they show little enzymatic activity in vitro, may 
      display significant catalytic activity in intact cells, and that the ability of 
      CA to enhance NBCe1 transport appears to depend primarily on its catalytic 
      activity.
FAU - Schueler, Christina
AU  - Schueler C
AD  - Abteilung fur Allgemeine Zoologie, FB Biologie, TU Kaiserslautern, 
      Kaiserslautern, Germany. christina.schueler@biologie.uni-kl.de
FAU - Becker, Holger M
AU  - Becker HM
FAU - McKenna, Robert
AU  - McKenna R
FAU - Deitmer, Joachim W
AU  - Deitmer JW
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20111104
PL  - United States
TA  - PLoS One
JT  - PloS one
JID - 101285081
RN  - 0 (Carbonic Anhydrase Inhibitors)
RN  - 0 (SLC4A4 protein, human)
RN  - 0 (Sodium-Bicarbonate Symporters)
RN  - EC 4.2.1.- (Carbonic Anhydrase I)
RN  - EC 4.2.1.- (Carbonic Anhydrase II)
RN  - EC 4.2.1.- (Carbonic Anhydrase III)
RN  - Z52H4811WX (Ethoxzolamide)
SB  - IM
MH  - Animals
MH  - Biological Transport
MH  - Blotting, Western
MH  - Carbonic Anhydrase I/antagonists & inhibitors/genetics/*metabolism
MH  - Carbonic Anhydrase II/antagonists & inhibitors/genetics/*metabolism
MH  - Carbonic Anhydrase III/antagonists & inhibitors/genetics/*metabolism
MH  - Carbonic Anhydrase Inhibitors/*pharmacology
MH  - Electrophysiology
MH  - Ethoxzolamide/*pharmacology
MH  - Female
MH  - Humans
MH  - Hydrogen-Ion Concentration
MH  - Oocytes/cytology/metabolism
MH  - Plasmids
MH  - Sodium-Bicarbonate Symporters/genetics/*metabolism
MH  - Xenopus laevis/metabolism
PMC - PMC3208603
COIS- Competing Interests: The authors have declared that no competing interests exist.
EDAT- 2011/11/15 06:00
MHDA- 2012/03/16 06:00
PMCR- 2011/11/04
CRDT- 2011/11/15 06:00
PHST- 2011/05/11 00:00 [received]
PHST- 2011/10/11 00:00 [accepted]
PHST- 2011/11/15 06:00 [entrez]
PHST- 2011/11/15 06:00 [pubmed]
PHST- 2012/03/16 06:00 [medline]
PHST- 2011/11/04 00:00 [pmc-release]
AID - PONE-D-11-08330 [pii]
AID - 10.1371/journal.pone.0027167 [doi]
PST - ppublish
SO  - PLoS One. 2011;6(11):e27167. doi: 10.1371/journal.pone.0027167. Epub 2011 Nov 4.