title: Correctors of mutant CFTR enhance subcortical cAMP-PKA signaling through modulating ezrin phosphorylation and cytoskeleton organization.
abstract: The most common mutation of the cystic fibrosis transmembrane regulator (CFTR) gene, F508del, produces a misfolded protein resulting in its defective trafficking to the cell surface and an impaired chloride secretion. Pharmacological treatments partially rescue F508del CFTR activity either directly by interacting with the mutant protein and/or indirectly by altering the cellular protein homeostasis. Here, we show that the phosphorylation of ezrin together with its binding to phosphatidylinositol-4,5-bisphosphate (PIP2) tethers the F508del CFTR to the actin cytoskeleton, stabilizing it on the apical membrane and rescuing the sub-membrane compartmentalization of cAMP and activated PKA. Both the small molecules trimethylangelicin (TMA) and VX-809, which act as 'correctors' for F508del CFTR by rescuing F508del-CFTR-dependent chloride secretion, also restore the apical expression of phosphorylated ezrin and actin organization and increase cAMP and activated PKA submembrane compartmentalization in both primary and secondary cystic fibrosis airway cells. Latrunculin B treatment or expression of the inactive ezrin mutant T567A reverse the TMA and VX-809-induced effects highlighting the role of corrector-dependent ezrin activation and actin re-organization in creating the conditions to generate a sub-cortical cAMP pool of adequate amplitude to activate the F508del-CFTR-dependent chloride secretion.
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Abbattiscianni
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Favia
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Mancini
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy.
authors.forename: Rosa A
authors.initials: RA
authors.lastname: Cardone
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Guerra
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK.
authors.forename: Stefania
authors.initials: S
authors.lastname: Monterisi
authors.affiliation: Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Castellani
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy.
authors.forename: Onofrio
authors.initials: O
authors.lastname: Laselva
authors.affiliation: Physiology and Pharmacology Department, Des Moines University, Des Moines, IA 50312, USA.
authors.forename: Francesca
authors.initials: F
authors.lastname: Di Sole
authors.affiliation: Department of Medical and Surgical Sciences, University of Foggia, Foggia 71122, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Conese
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK valeria.casavola@uniba.it manuela.zaccolo@balliol.ox.ac.uk.
authors.forename: Manuela
authors.initials: M
authors.lastname: Zaccolo
authors.affiliation: Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari 70126, Italy valeria.casavola@uniba.it manuela.zaccolo@balliol.ox.ac.uk.
authors.forename: Valeria
authors.initials: V
authors.lastname: Casavola
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002712:Chlorides / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000235:genetics* / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D010766:Phosphorylation; D051381:Rats; D017384:Sequence Deletion; D015398:Signal Transduction; D000099149:Ezrin
chemical_list: D000199:Actins; D002712:Chlorides; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D003598:Cytoskeletal Proteins; D000099149:Ezrin
keywords: Airway cells; Correctors; Cystic fibrosis; FRET; PKA; cAMP