cDNA cloning and localization of a band 3-related protein from ileum

A. Chow, J. W. Dobbins, P. S. Aronson, P. Igarashi

Research output: Contribution to journalArticlepeer-review

70 Scopus citations


A Cl--HCO3/- exchanger in the brush-border membrane mediates active Cl- absorption and regulates intracellular pH in rabbit ileum. The molecular identity of the ileal Cl--HCO3/- exchanger has not been established. The best-characterized plasma membrane Cl--HCO3/- exchanger is erythroid band 3. Structurally related proteins in nonerythroid tissues comprise an anion exchanger (AE) family. We used the polymerase chain reaction to amplify and clone a cDNA encoding an ileal band 3-related protein (B3RP) from rabbit ileal enterocytes. The composite sequence is 3,909 bp and is predicted to encode a protein of 136 kDa. The deduced amino acid sequence is 95% identical to murine renal AE2, indicating that ileal B3RP is rabbit AE2. Antisera generated against a cytoplasmic fragment of ileal B3RP recognized a 160- to 170-kDa polypeptide in the brush-border membrane, but not the basolateral membrane, of ileal crypt and villus enterocytes. This correlates with previous studies indicating that a Cl--HCO3/- exchange is present in brush-border but not basolateral membrane vesicles from rabbit ileal enterocytes. We conclude that ileal B3RP is a product of the AE gene family, and is present in the brush-border of ileal enterocytes, where it may mediate Cl--HCO3/- exchange.

Original languageEnglish (US)
Pages (from-to)G345-G352
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Issue number3 26-3
StatePublished - 1992


  • anion exchanger
  • brush border
  • chloride-bicarbonate exchange
  • villus and crypt enterocytes

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)


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