title: Inhibition of protein kinase CK2 closes the CFTR Cl channel, but has no effect on the cystic fibrosis mutant deltaF508-CFTR.
abstract: BACKGROUND
  Deletion of phenylalanine-508 (DeltaF508) from the first nucleotide-binding domain (NBD1) in the wild-type cystic fibrosis (CF) transmembrane-conductance regulator (wtCFTR) causes CF. However, the mechanistic relationship between DeltaF508-CFTR and the diversity of CF disease is unexplained. The surface location of F508 on NBD1 creates the potential for protein-protein interactions and nearby, lies a consensus sequence (SYDE) reported to control the pleiotropic protein kinase CK2.
  
  
  METHODS
  Electrophysiology, immunofluorescence and biochemistry applied to CFTR-expressing cells, Xenopus oocytes, pancreatic ducts and patient biopsies.
  
  
  RESULTS
  Irrespective of PKA activation, CK2 inhibition (ducts, oocytes, cells) attenuates CFTR-dependent Cl(-) transport, closing wtCFTR in cell-attached membrane patches. CK2 and wtCFTR co-precipitate and CK2 co-localized with wtCFTR (but not DeltaF508-CFTR) in apical membranes of human airway biopsies. Comparing wild-type and DeltaF508CFTR expressing oocytes, only DeltaF508-CFTR Cl(-) currents were insensitive to two CK2 inhibitors. Furthermore, wtCFTR was inhibited by injecting a peptide mimicking the F508 region, whereas the DeltaF508-equivalent peptide had no effect.
  
  
  CONCLUSIONS
  CK2 controls wtCFTR, but not DeltaF508-CFTR. Others find that peptides from the F508 region of NBD1 allosterically control CK2, acting through F508. Hence, disruption of CK2-CFTR interaction by DeltaF508-CFTR might disrupt multiple, membrane-associated, CK2-dependent pathways, creating a new molecular disease paradigm for deleted F508 in CFTR.
authors.affiliation: Centre for Cardiovascular and Lung Biology, University of Dundee, Ninewells Hospital, UK.
authors.forename: Kate J
authors.initials: KJ
authors.lastname: Treharne
authors.forename: Zhe
authors.initials: Z
authors.lastname: Xu
authors.forename: Jeng-Haur
authors.initials: JH
authors.lastname: Chen
authors.forename: O Giles
authors.initials: OG
authors.lastname: Best
authors.forename: Diane M
authors.initials: DM
authors.lastname: Cassidy
authors.forename: Dieter C
authors.initials: DC
authors.lastname: Gruenert
authors.forename: Péter
authors.initials: P
authors.lastname: Hegyi
authors.forename: Michael A
authors.initials: MA
authors.lastname: Gray
authors.forename: David N
authors.initials: DN
authors.lastname: Sheppard
authors.forename: Karl
authors.initials: K
authors.lastname: Kunzelmann
authors.forename: Anil
authors.initials: A
authors.lastname: Mehta
mesh_terms: D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D047390:Casein Kinase II / Q000032:analysis / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002460:Cell Line; D018118:Chloride Channels / Q000378:metabolism*; D006224:Cricetinae; D000242:Cyclic AMP / Q000378:metabolism; D003550:Cystic Fibrosis / Q000235:genetics; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D055724:Electrophysiological Phenomena; D006168:Guinea Pigs; D006801:Humans; D047468:Immunoprecipitation; D008969:Molecular Sequence Data; D009154:Mutation; D009865:Oocytes / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D014981:Xenopus
chemical_list: D018118:Chloride Channels; C093349:cystic fibrosis transmembrane conductance regulator delta F508; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000242:Cyclic AMP; D047390:Casein Kinase II