PMID- 17353189
OWN - NLM
STAT- MEDLINE
DCOM- 20070614
LR  - 20210209
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 282
IP  - 18
DP  - 2007 May 4
TI  - Carbonic anhydrase II increases the activity of the human electrogenic Na+/HCO3- 
      cotransporter.
PG  - 13508-21
AB  - Several acid/base-coupled membrane transporters, such as the electrogenic 
      sodium-bicarbonate cotransporter (NBCe1), have been shown to bind to different 
      carbonic anhydrase isoforms to create a "transport metabolon." We have expressed 
      NBCe1 derived from human kidney in oocytes of Xenopus leavis and determined its 
      transport activity by recording the membrane current in voltage clamp, and the 
      cytosolic H(+) and Na(+) concentrations using ion-selective microelectrodes. When 
      carbonic anhydrase isoform II (CAII) had been injected into oocytes, the membrane 
      current and the rate of cytosolic Na(+) rise, indicative for NBCe1 activity, 
      increased significantly with the amount of injected CAII (2-200 ng). The CAII 
      inhibitor ethoxyzolamide reversed the effects of CAII on the NBCe1 activity. 
      Co-expressing wild-type CAII or NH(2)-terminal mutant CAII together with NBCe1 
      provided similar results, whereas co-expressing the catalytically inactive CAII 
      mutant V143Y had no effect on NBCe1 activity. Mass spectrometric analysis and the 
      rate of cytosolic H(+) change following addition of CO(2)/HCO(3)(-) confirmed the 
      catalytic activity of injected and expressed CAII in oocytes. Our results show 
      that the transport capacity of NBCe1 is enhanced by the catalytic activity of 
      CAII, in line with the notion that CAII forms a transport metabolon with NBCe1.
FAU - Becker, Holger M
AU  - Becker HM
AD  - Abteilung fur Allgemeine Zoologie, Fachbereich Biologie, Technische Universitat 
      Kaiserslautern, P. O. Box 3049, D-67653 Kaiserslautern, Germany. 
      h.becker@biologie.uni-kl.de
FAU - Deitmer, Joachim W
AU  - Deitmer JW
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20070312
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Carbonic Anhydrase Inhibitors)
RN  - 0 (Sodium-Bicarbonate Symporters)
RN  - 7YNJ3PO35Z (Hydrogen)
RN  - 9NEZ333N27 (Sodium)
RN  - EC 4.2.1.- (Carbonic Anhydrase II)
RN  - Z52H4811WX (Ethoxzolamide)
SB  - IM
MH  - Amino Acid Substitution
MH  - Animals
MH  - Carbonic Anhydrase II/antagonists & inhibitors/genetics/*metabolism
MH  - Carbonic Anhydrase Inhibitors/pharmacology
MH  - Ethoxzolamide/pharmacology
MH  - Gene Expression
MH  - Humans
MH  - Hydrogen/metabolism
MH  - Ion Transport/drug effects/genetics
MH  - Kidney/metabolism
MH  - Membrane Potentials/drug effects/genetics
MH  - Microelectrodes
MH  - Mutation, Missense
MH  - Oocytes/cytology
MH  - Sodium/metabolism
MH  - Sodium-Bicarbonate Symporters/genetics/*metabolism
MH  - Xenopus
EDAT- 2007/03/14 09:00
MHDA- 2007/06/15 09:00
CRDT- 2007/03/14 09:00
PHST- 2007/03/14 09:00 [pubmed]
PHST- 2007/06/15 09:00 [medline]
PHST- 2007/03/14 09:00 [entrez]
AID - S0021-9258(17)47428-X [pii]
AID - 10.1074/jbc.M700066200 [doi]
PST - ppublish
SO  - J Biol Chem. 2007 May 4;282(18):13508-21. doi: 10.1074/jbc.M700066200. Epub 2007 
      Mar 12.