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Apparent affinity of CFTR for ATP is increased by continuous kinase activity
Author(s) -
Szellas Tanjef,
Nagel Georg
Publication year - 2003
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)03892-9
Subject(s) - protein kinase a , biochemistry , chemistry , phosphorylation , cystic fibrosis transmembrane conductance regulator , mitogen activated protein kinase kinase , protein subunit , kinase , microbiology and biotechnology , biology , gene
The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel which is activated by protein phosphorylation and nucleoside triphosphates. We demonstrate here that fusion of the soluble catalytic subunit of cAMP‐dependent protein kinase to the membrane protein bacteriorhodopsin yields a constitutively active protein kinase which activates CFTR effectively. As it is membrane‐bound it is particularly useful for continuous perfusion of excised inside‐out patches. We also tested the effect of a naturally membrane‐bound protein kinase, cGMP‐dependent protein kinase II, on CFTR. Both kinases, when continuously active, increase apparent affinity of CFTR to ATP about two‐fold emphasizing the role of phosphorylation in modulating the interaction of ATP with the nucleotide binding domains.