The cystic fibrosis transmembrane conductance regulator activates aquaporin 3 in airway epithelial cells.
Enhanced osmotic water permeability has been observed in Xenopus oocytes expressing cystic fibrosis transmembrane conductance regulator (CFTR) protein. Subsequent studies have shown that CFTR activates an endogenous water permeability in oocytes, but that CFTR itself is not the water channel. Here, we show CFTR-dependent activation of endogenous water permeability in normal but not in cystic fibrosis human airway epithelial cells. Cell volume was measured by novel confocal x-z laser scanning microscopy. Glycerol uptake and antisense studies suggest CFTR-dependent regulation of aquaporin 3 (AQP3) water channels in airway epithelial cells. Regulatory interaction was confirmed by coexpression of CFTR and AQP3 cloned from human airways in Xenopus oocytes and of CFTR and rat AQP3 in Chinese hamster ovary cells. These findings indicate that CFTR is a regulator of AQP3 in airway epithelial cells.
Schreiber
R
R
Physiologisches Institut, Albert-Ludwigs-Universität Freiburg, Hermann-Herder-Strasse 7, 79104 Freiburg, Germany.
Nitschke
R
R
Greger
R
R
Kunzelmann
K
K
D000818:Animals; D051400:Aquaporin 3; D020346:Aquaporins / Q000378:metabolism*; D001483:Base Sequence; D016466:CHO Cells; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000378:metabolism*; D017931:DNA Primers; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D009865:Oocytes / Q000378:metabolism; D051381:Rats; D014132:Trachea / Q000166:cytology / Q000378:metabolism*; D014981:Xenopus
C496027:AQP3 protein, human; C496029:Aqp3 protein, rat; D020346:Aquaporins; C505032:CFTR protein, human; D017931:DNA Primers; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D051400:Aquaporin 3; D000242:Cyclic AMP; D005990:Glycerol