PMID- 11875254
OWN - NLM
STAT- MEDLINE
DCOM- 20020424
LR  - 20061115
IS  - 1590-8577 (Electronic)
IS  - 1590-8577 (Linking)
VI  - 2
IP  - 4 Suppl
DP  - 2001 Jul
TI  - Carbonic anhydrase: in the driver's seat for bicarbonate transport.
PG  - 165-70
AB  - Carbonic anhydrases are a widely expressed family of enzymes that catalyze the 
      reversible reaction: CO(2) + H(2)O <=> HCO(3)(-) + H(+). These enzymes therefore 
      both produce HCO(3)(-) for transport across membranes and consume HCO(3)(-) that 
      has been transported across membranes. Thus these enzymes could be expected to 
      have a key role in driving the transport of HCO(3)(-) across cells and epithelial 
      layers. Plasma membrane anion exchange proteins (AE) transport chloride and 
      bicarbonate across most mammalian membranes in a one-for-one exchange reaction 
      and act as a model for our understanding of HCO(3)(-) transport processes. 
      Recently it was shown that AE1, found in erythrocytes and kidney, binds carbonic 
      anhydrase II (CAII) via the cytosolic C-terminal tail of AE1. To examine the 
      physiological consequences of the interaction between CAII and AE1, we 
      characterized Cl(-)/HCO(3)(-) exchange activity in transfected HEK293 cells. 
      Treatment of AE1-transfected cells with acetazolamide, a CAII inhibitor, almost 
      fully inhibited anion exchange activity, indicating that endogenous CAII activity 
      is essential for transport. Further experiments to examine the role of the 
      AE1/CAII interaction will include measurements of the transport activity of AE1 
      following mutation of the CAII binding site. In a second approach a functionally 
      inactive CA mutant, V143Y, will be co-expressed with AE1 in HEK293 cells. Since 
      over expression of V143Y CAII would displace endogenous wild-type CAII from AE1, 
      a loss of transport activity would be observed if binding to the AE1 C-terminus 
      is required for transport.
FAU - Sterling, D
AU  - Sterling D
AD  - Membrane Transport Group and CIHR Group in Molecular Biology of Membrane 
      Proteins, Department of Physiology, University of Alberta. Edmonton, Canada.
FAU - Reithmeier, R A
AU  - Reithmeier RA
FAU - Casey, J R
AU  - Casey JR
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Review
PL  - England
TA  - JOP
JT  - JOP : Journal of the pancreas
JID - 101091810
RN  - 0 (Antiporters)
RN  - 0 (Bicarbonates)
RN  - EC 4.2.1.1 (Carbonic Anhydrases)
SB  - IM
MH  - Animals
MH  - Antiporters/physiology
MH  - Bicarbonates/*metabolism
MH  - Biological Transport, Active/physiology
MH  - Carbonic Anhydrases/*physiology
MH  - Humans
RF  - 21
EDAT- 2002/03/05 10:00
MHDA- 2002/04/25 10:01
CRDT- 2002/03/05 10:00
PHST- 2002/03/05 10:00 [pubmed]
PHST- 2002/04/25 10:01 [medline]
PHST- 2002/03/05 10:00 [entrez]
AID - v02i04a07 [pii]
PST - ppublish
SO  - JOP. 2001 Jul;2(4 Suppl):165-70.