title: Protein kinase C activates chloride conductance in C127 cells stably expressing the cystic fibrosis gene.
abstract: The regulatory domain (R domain) of the cystic fibrosis transmembrane conductance regulator (CFTR) is phosphorylated by protein kinase A and protein kinase C (PKC) in vivo (Picciotto, M. R., Cohn, J. A., Bertuzzi, G., Greengard, P., and Nairn, A. C. (1992) J. Biol. Chem. 267, 12742-12752), but so far the functional effect of the PKC-dependent phosphorylation has not been clarified. We investigated the effect of PKC on the CFTR-mediated Cl- transport by treating with phorbol 12-myristate 13-acetate (PMA), the cell line C127i stably expressing CFTR wild type (C127 CFTRw/t), or CFTR bearing the most common mutation deltaF508 (C127 CFTRdF508). We show that PMA activates Cl- efflux in C127 CFTRw/t, but not in C127 CFTRdF508 and C127i. The PMA-dependent activation of CFTR is not mediated by increase of intracellular [cAMP] and is not the result of a primary activation of a K+ conductive pathway. These results strongly suggest that PKC activates directly CFTR-mediated Cl- transport.
authors.affiliation: Cystic Fibrosis Center, Ospedale Civile Maggiore, Verona, Italy.
authors.forename: M C
authors.initials: MC
authors.lastname: Dechecchi
authors.forename: A
authors.initials: A
authors.lastname: Tamanini
authors.forename: G
authors.initials: G
authors.lastname: Berton
authors.forename: G
authors.initials: G
authors.lastname: Cabrini
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D018118:Chloride Channels; D002712:Chlorides / Q000378:metabolism*; D003550:Cystic Fibrosis / Q000235:genetics*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D006801:Humans; D007473:Ion Channels / Q000502:physiology*; D007700:Kinetics; D008565:Membrane Proteins / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D051379:Mice; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
chemical_list: C505032:CFTR protein, human; D018118:Chloride Channels; D002712:Chlorides; D007473:Ion Channels; D008565:Membrane Proteins; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D015124:8-Bromo Cyclic Adenosine Monophosphate; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D011494:Protein Kinases; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D015056:1-Methyl-3-isobutylxanthine