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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4 Suppl
pubmed:dateCreated
2002-3-4
pubmed:abstractText
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.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
1590-8577
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
165-70
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Carbonic anhydrase: in the driver's seat for bicarbonate transport.
pubmed:affiliation
Membrane Transport Group and CIHR Group in Molecular Biology of Membrane Proteins, Department of Physiology, University of Alberta. Edmonton, Canada.
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't