Treharne KJ, Xu Z, Chen JH, Best OG, Cassidy DM, Gruenert DC, Hegyi P, Gray MA, Sheppard DN, Kunzelmann K, Mehta A. Inhibition of protein kinase CK2 closes the CFTR Cl channel, but has no effect on the cystic fibrosis mutant deltaF508-CFTR.
Cell Physiol Biochem 2009;
24:347-60. [PMID:
19910675 DOI:
10.1159/000257427]
[Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2009] [Indexed: 01/10/2023] Open
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.
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