Stimulation of beta 2-adrenergic receptor increases cystic fibrosis transmembrane conductance regulator expression in human airway epithelial cells through a cAMP/protein kinase A-independent pathway.
PSD-95/Dlg-A/ZO-1 (PDZ) domains play an essential role in determining cell polarity. The Na(+)/H(+) exchanger regulatory factor (NHERF), also known as EBP50, contains two PDZ domains that mediate the assembly of transmembrane and cytosolic proteins into functional signal transduction complexes. Moreover, it has been shown that cystic fibrosis transmembrane conductance regulator (CFTR) and beta(2)-adrenergic receptor (beta(2)AR) bind equally well to the PDZ1 domain of EBP50. We hypothesized that beta(2)AR activation may regulate CFTR protein expression. To verify this, we evaluated the effects of a pharmacologically relevant concentration of salmeterol (2.10(-7) m), a long acting beta(2)AR agonist, on CFTR expression in primary human airway epithelial cells (HAEC). beta(2)AR stimulation induced a time-dependent increase in apical CFTR protein expression, with a maximal response reached after treatment for 24 h. This effect was post-transcriptional, dependent upon the beta(2)AR agonist binding to beta(2)AR and independent of the known beta(2)AR agonist-mediated cAMP/PKA pathway. We demonstrated by immunohistochemistry that CFTR, beta(2)AR, and EBP50 localize to the apical membrane of HAEC. Analyses of anti-EBP50 protein immunoprecipitate showed that salmeterol induced an increase in the amount of CFTR that binds to EBP50. These data suggest that beta(2)AR activation regulates the association of CFTR with EBP50 in polarized HAEC.
Taouil
Karima
K
INSERM 514, IFR 53, Centre Hospitalier Universitaire Maison Blanche, Reims, 51092 Cedex, France.
Hinnrasky
Jocelyne
J
Hologne
Coralie
C
Corlieu
Pascal
P
Klossek
Jean-Michel
JM
Puchelle
Edith
E
D002352:Carrier Proteins / Q000378:metabolism; D016764:Cell Polarity; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000096:biosynthesis*; D006801:Humans; D010750:Phosphoproteins / Q000378:metabolism; D017434:Protein Structure, Tertiary; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism*; D015398:Signal Transduction; D017923:Sodium-Hydrogen Exchangers
C505032:CFTR protein, human; D002352:Carrier Proteins; D010750:Phosphoproteins; D018343:Receptors, Adrenergic, beta-2; D017923:Sodium-Hydrogen Exchangers; C093376:sodium-hydrogen exchanger regulatory factor; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases