Classical and atypical agonists activate M1 muscarinic acetylcholine receptors through common mechanisms

0448654 - FGÚ 2016 RIV GB eng J - Journal Article
Randáková, Alena - Dolejší, Eva - Rudajev, Vladimír - Zimčík, Pavel - Doležal, Vladimír - El-Fakahany, E. E. - Jakubík, Jan
Classical and atypical agonists activate M1 muscarinic acetylcholine receptors through common mechanisms.
Pharmacological Research. Roč. 97, Jul 2015 (2015), s. 27-39. ISSN 1043-6618. E-ISSN 1096-1186
R&D Projects: GA ČR(CZ) GA305/09/0681; GA ČR(CZ) GBP304/12/G069; GA MŠMT(CZ) EE2.3.30.0025
Institutional support: RVO:67985823
Keywords : muscarinic acetylcholine receptors * atypical agonists * xanomeline * activation mechanism
Subject RIV: ED - Physiology
Impact factor: 4.816, year: 2015

We mutated key amino acids of the human variant of the M-1 muscarinic receptor that target ligand binding, receptor activation, and receptor-G protein interaction. We compared the effects of these mutations on the action of two atypical M-1 functionally preferring agonists (N-desmethylclozapine and xanomeline) and two classical non-selective orthosteric agonists (carbachol and oxotremorine). Mutations of D105 in the orthosteric binding site and mutation of D99 located out of the orthosteric binding site decreased affinity of all tested agonists that was translated as a decrease in potency in accumulation of inositol phosphates and intracellular calcium mobilization. Mutation of D105 decreased the potency of the atypical agonist xanomeline more than that of the classical agonists carbachol and oxotremorine. Mutation of the residues involved in receptor activation (D71) and coupling to G-proteins (R123) completely abolished the functional responses to both classical and atypical agonists. Our data show that both classical and atypical agonists activate hM(1) receptors by the same molecular switch that involves D71 in the second transmembrane helix. The principal difference among the studied agonists is rather in the way they interact with D105 in the orthosteric binding site. Furthermore, our data demonstrate a key role of D105 in xanomeline wash-resistant binding and persistent activation of hM(1) by wash-resistant xanomeline
Permanent Link: http://hdl.handle.net/11104/0250288