Aberrant CFTR-dependent HCO3- transport in mutations associated with cystic fibrosis

Joo Young Choi, Daniella Muallem, Kirill Kiselyov, Min Goo Lee, Philip J. Thomas, Shmuel Muallem

Research output: Contribution to journalArticlepeer-review

305 Scopus citations

Abstract

Cystic fibrosis (CF) is a disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). Initially, Cl- conductance in the sweat duct was discovered to be impaired in CF1, a finding that has been extended to all CFTR-expressing cells. Subsequent cloning of the gene showed that CFTR functions as a cyclic-AMP-regulated Cl- channel and some CF-causing mutations inhibit CFTR Cl- channel activity. The identification of additional CF-causing mutants with normal Cl- channel activity indicates, however, that other CFTR-dependent processes contribute to the disease. Indeed, CFTR regulates other transporters, including Cl--coupled HCO3- transport. Alkaline fluids are secreted by normal tissues, whereas acidic fluids are secreted by mutant CFTR-expressing tissues, indicating the importance of this activity. HCO3- and pH affect mucin viscosity and bacterial binding. We have examined Cl--coupled HCO3- transport by CFTR mutants that retain substantial or normal Cl- channel activity. Here we show that mutants reported to be associated with CF with pancreatic insufficiency do not support HCO3- transport, and those associated with pancreatic sufficiency show reduced HCO3- transport. Our findings demonstrate the importance of HCO3- transport in the function of secretory epithelia and in CF.

Original languageEnglish (US)
Pages (from-to)94-97
Number of pages4
JournalNature
Volume410
Issue number6824
DOIs
StatePublished - Mar 1 2001

ASJC Scopus subject areas

  • General

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