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The human muscarinic M1 acetylcholine receptor, when expressed in CHO cells, activates and downregulates both G q α and G 11 α equally and non‐selectively
Author(s) -
Mullaney Ian,
Mitchell Fiona M.,
McCallum J.Fraser,
Buckley Noel J.,
Milligan Graeme
Publication year - 1993
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 - 10.1016/0014-5793(93)81401-k
Subject(s) - carbachol , muscarinic acetylcholine receptor , muscarinic acetylcholine receptor m5 , agonist , muscarinic acetylcholine receptor m1 , muscarinic acetylcholine receptor m2 , g protein , receptor , microbiology and biotechnology , muscarinic acetylcholine receptor m3 , chinese hamster ovary cell , transfection , gq alpha subunit , chemistry , acetylcholine receptor , acetylcholine , muscarinic agonist , biology , endocrinology , biochemistry , gene
CHO cells express both of the phosphoinositidase C‐linked G‐proteins G q and G 11 G 11 α is some 2.5‐fold more highly expressed than G q α in membranes of these cells. Following transfection and stable expression of CHO cells with DNA encoding the human muscarinic M1 acetylcholine (HM1) receptor, chronic treatment of the cells with the cholinergic agonist carbachol resulted in down‐regulation of membrane levels of both G q α and G 11α . Dose‐response curves to carbachol produced identical EC 50 values for agonist‐induced down‐regulation of the two G‐proteins and both were down‐regulated with the same time course. These data indicate that the HM1 receptor interacts with and activates both G q α and G 11 α equivalently and non‐selectively in a whole cell system in which the receptor has access to both G‐proteins.