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Activation of nematode G protein GOA‐1 by the human muscarinic acetylcholine receptor M 2 subtype
Author(s) -
Minaba Masaomi,
Ichiyama Susumu,
Kojima Katsura,
Ozaki Mamiko,
Kato Yusuke
Publication year - 2006
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2006.05542.x
Subject(s) - muscarinic acetylcholine receptor , g protein , heterotrimeric g protein , gtpgammas , muscarinic acetylcholine receptor m2 , muscarinic acetylcholine receptor m1 , biology , receptor , acetylcholine , muscarinic acetylcholine receptor m5 , guanosine , muscarinic acetylcholine receptor m3 , gtp binding protein regulators , signal transduction , microbiology and biotechnology , g protein coupled receptor , endocrinology , medicine , biochemistry
Signal transduction mediated by heterotrimeric G proteins regulates a wide variety of physiological functions. We are interested in the manipulation of G‐protein‐mediating signal transduction using G‐protein‐coupled receptors, which are derived from evolutionarily distant organisms and recognize unique ligands. As a model, we tested the functionally coupling GOA‐1, Gα i/o ortholog in the nematode Caenorhabditis elegans , with the human muscarinic acetylcholine receptor M 2 subtype (M 2 ), which is one of the mammalian Gα i/o ‐coupled receptors. GOA‐1 and M 2 were prepared as a fusion protein using a baculovirus expression system. The affinity of the fusion protein for GDP was decreased by addition of a muscarinic agonist, carbamylcholine and the guanosine 5′‐[3‐ O ‐thio]triphosphate ([ 35 S]GTPγS) binding was increased with an increase in the carbamylcholine concentrations in a dose‐dependent manner. These effects evoked by carbamylcholine were completely abolished by a full antagonist, atropine. In addition, the affinity for carbamylcholine decreased under the presence of GTP as reported for M 2 –Gα i/o coupling. These results indicate that the M 2 activates GOA‐1 as well as Gα i/o .