title: cGMP stimulation of cystic fibrosis transmembrane conductance regulator Cl- channels co-expressed with cGMP-dependent protein kinase type II but not type Ibeta.
abstract: In order to investigate the involvement of cGMP-dependent protein kinase (cGK) type II in cGMP-provoked intestinal Cl- secretion, cGMP-dependent activation and phosphorylation of cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels was analyzed after expression of cGK II or cGK Ibeta in intact cells. An intestinal cell line which stably expresses CFTR (IEC-CF7) but contains no detectable endogenous cGK II was infected with a recombinant adenoviral vector containing the cGK II coding region (Ad-cGK II) resulting in co-expression of active cGK II. In these cells, CFTR was activated by membrane-permeant analogs of cGMP or by the cGMP-elevating hormone atrial natriuretic peptide as measured by 125I- efflux assays and whole-cell patch clamp analysis. In contrast, infection with recombinant adenoviruses expressing cGK Ibeta or luciferase did not convey cGMP sensitivity to CFTR in IEC-CF7 cells. Concordant with the activation of CFTR by only cGK II, infection with Ad-cGK II but not Ad-cGK Ibeta enabled cGMP analogs to increase CFTR phosphorylation in intact cells. These and other data provide evidence that endogenous cGK II is a key mediator of cGMP-provoked activation of CFTR in cells where both proteins are co-localized, e. g. intestinal epithelial cells. Furthermore, they demonstrate that neither the soluble cGK Ibeta nor cAMP-dependent protein kinase are able to substitute for cGK II in this cGMP-regulated function.
authors.affiliation: Department of Biochemistry, Cardiovascular Research Institute COEUR, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, 3000 DR Rotterdam, The Netherlands.
authors.forename: A B
authors.initials: AB
authors.lastname: Vaandrager
authors.forename: B C
authors.initials: BC
authors.lastname: Tilly
authors.forename: A
authors.initials: A
authors.lastname: Smolenski
authors.forename: S
authors.initials: S
authors.lastname: Schneider-Rasp
authors.forename: A G
authors.initials: AG
authors.lastname: Bot
authors.forename: M
authors.initials: M
authors.lastname: Edixhoven
authors.forename: B J
authors.initials: BJ
authors.lastname: Scholte
authors.forename: T
authors.initials: T
authors.lastname: Jarchau
authors.forename: U
authors.initials: U
authors.lastname: Walter
authors.forename: S M
authors.initials: SM
authors.lastname: Lohmann
authors.forename: W C
authors.initials: WC
authors.lastname: Poller
authors.forename: H R
authors.initials: HR
authors.lastname: de Jonge
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D002460:Cell Line; D065101:Chloride Channel Agonists; D006152:Cyclic GMP / Q000494:pharmacology*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000819:agonists*; D018014:Gene Transfer Techniques; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010766:Phosphorylation; D051381:Rats
chemical_list: D065101:Chloride Channel Agonists; D007527:Isoenzymes; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP