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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
2002-10-9
pubmed:abstractText
COOH-terminal cytoplasmic tails of chloride/bicarbonate anion exchangers (AE) bind cytosolic carbonic anhydrase II (CAII) to form a bicarbonate transport metabolon, a membrane protein complex that accelerates transmembrane bicarbonate flux. To determine whether interaction with CAII affects the downregulated in adenoma (DRA) chloride/bicarbonate exchanger, anion exchange activity of DRA-transfected HEK-293 cells was monitored by following changes in intracellular pH associated with bicarbonate transport. DRA-mediated bicarbonate transport activity of 18 +/- 1 mM H+ equivalents/min was inhibited 53 +/- 2% by 100 mM of the CAII inhibitor, acetazolamide, but was unaffected by the membrane-impermeant carbonic anhydrase inhibitor, 1-[5-sulfamoyl-1,3,4-thiadiazol-2-yl-(aminosulfonyl-4-phenyl)]-2,6-dimethyl-4-phenyl-pyridinium perchlorate. Compared with AE1, the COOH-terminal tail of DRA interacted weakly with CAII. Overexpression of a functionally inactive CAII mutant, V143Y, reduced AE1 transport activity by 61 +/- 4% without effect on DRA transport activity (105 +/- 7% transport activity relative to DRA alone). We conclude that cytosolic CAII is required for full DRA-mediated bicarbonate transport. However, DRA differs from other bicarbonate transport proteins because its transport activity is not stimulated by direct interaction with CAII.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0363-6143
pubmed:author
pubmed:issnType
Print
pubmed:volume
283
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
C1522-9
pubmed:dateRevised
2011-11-17
pubmed:meshHeading
pubmed:year
2002
pubmed:articleTitle
The functional and physical relationship between the DRA bicarbonate transporter and carbonic anhydrase II.
pubmed:affiliation
Canadian Institutes of Health Research Membrane Protein Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta, Canada T6G 2H7.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't