Referenced in: none

Automatically associated channels: ClC2 , ClC4

Title: Additional disruption of the ClC-2 Cl(-) channel does not exacerbate the cystic fibrosis phenotype of cystic fibrosis transmembrane conductance regulator mouse models.

Authors: Anselm A Zdebik, John E Cuffe, Marko Bertog, Christoph Korbmacher, Thomas J Jentsch

Journal, date & volume: J. Biol. Chem., 2004 May 21 , 279, 22276-83

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15007059

Abstract
Cystic fibrosis is a fatal inherited disease that is caused by mutations in the gene encoding a cAMP-activated chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR). It has been suggested that the cystic fibrosis phenotype might be modulated by the presence of other Cl(-) channels that are coexpressed with CFTR in some epithelial cells. Because the broadly expressed plasma membrane Cl(-) channel, ClC-2, is present in the tissues whose function is compromised in cystic fibrosis, we generated mice with a disruption of both Cl(-) channel genes. No morphological changes in their intestine, lung, or pancreas, tissues affected by cystic fibrosis, were observed in these mice. The mortality was not increased over that observed with a complete lack of functional CFTR. Surprisingly, mice expressing mutant CFTR (deletion of phenylalanine 508), survived longer when ClC-2 was disrupted additionally. Currents across colonic epithelia were investigated in Ussing chamber experiments. The disruption of ClC-2, in addition to CFTR, did not decrease Cl(-) secretion. Colon expressing wild-type CFTR even secreted more Cl(-) when ClC-2 was disrupted, although CFTR transcript levels were unchanged. It is concluded that ClC-2 is unlikely to be a candidate rescue channel in cystic fibrosis. Our data are consistent with a model in which ClC-2 is located in the basolateral membrane.