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Role of receptor kinase in short‐term desensitization of cardiac muscarinic K + channels expressed in Chinese hamster ovary cells
Author(s) -
Shui Z.,
Khan I. A.,
Tsuga H.,
Haga T.,
Boyett M. R.
Publication year - 1998
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1998.325bt.x
Subject(s) - chinese hamster ovary cell , muscarinic acetylcholine receptor , desensitization (medicine) , term (time) , chemistry , medicine , endocrinology , microbiology and biotechnology , cricetulus , receptor , biology , physics , quantum mechanics
1 The cardiac muscarinic receptor‐K + channel system was reconstructed in Chinese hamster ovary (CHO) cells by transfecting the cells with the various components of the system. The activity of the muscarinic K + channel was measured with the cell‐attached configuration of the patch clamp technique. 2 In CHO cells transfected with the channel (Kir3.1/Kir3.4), receptor (hm2) and receptor kinase (GRK2), on exposure to agonist, there was a decline in channel activity as a result of desensitization, similar to that in atrial cells. 3 Whereas the desensitization was almost abolished by not transfecting with the receptor kinase or by transfecting with a mutant receptor lacking phosphorylation sites, it was only reduced (by ≈39 %) by transfecting with a mutant receptor kinase with little kinase activity. 4 These results suggest that the receptor kinase is responsible for desensitization of the muscarinic K + channel and that this involves phosphorylation‐dependent and ‐independent mechanisms.