scholarly journals Position of Transmembrane Helix 6 Determines Receptor G Protein Coupling Specificity

2014 ◽  
Vol 136 (32) ◽  
pp. 11244-11247 ◽  
Author(s):  
Alexander S. Rose ◽  
Matthias Elgeti ◽  
Ulrich Zachariae ◽  
Helmut Grubmüller ◽  
Klaus Peter Hofmann ◽  
...  
Keyword(s):  
G Protein ◽  
Transmembrane Helix ◽  
G Protein Coupling ◽  
Protein Coupling ◽  
Coupling Specificity

scholarly journals The allosteric enhancer PD81,723 increases chimaeric A1/A2A adenosine receptor coupling with Gs

2006 ◽  
Vol 396 (1) ◽  
pp. 139-146 ◽  
Author(s):  
Samita Bhattacharya ◽  
Rebecca L. Youkey ◽  
Kobina Ghartey ◽  
Matthew Leonard ◽  
Joel Linden ◽  
...  
Keyword(s):  
G Protein ◽  
Adenosine Receptor ◽  
Intracellular Loop ◽  
Dissociation Kinetics ◽  
A2a Adenosine Receptor ◽  
G Protein Coupling ◽  
Protein Coupling ◽  
Receptor Coupling ◽  
A1 Receptor ◽  
Coupling Specificity

PD81,723 {(2-amino-4,5-dimethyl-3-thienyl)-[3-(trifluromethyl)-phenyl]methanone} is a selective allosteric enhancer of the Gi-coupled A1 AR (adenosine receptor) that is without effect on Gs-coupled A2A ARs. PD81,723 elicits a decrease in the dissociation kinetics of A1 AR agonist radioligands and an increase in functional agonist potency. In the present study, we sought to determine whether enhancer sensitivity is dependent on coupling domains or G-protein specificity of the A1 AR. Using six chimaeric A1/A2A ARs, we show that the allosteric effect of PD81,723 is maintained in a chimaera in which the predominant G-protein-coupling domain of the A1 receptor, the 3ICL (third intracellular loop), is replaced with A2A sequence. These chimaeric receptors are dually coupled with Gs and Gi, and PD81,723 increases the potency of N6-cyclopentyladenosine to augment cAMP accumulation with or without pretreatment of cells with pertussis toxin. Thus PD81,723 has similar functional effects on chimaeric receptors with A1 transmembrane sequences that couple with Gi or Gs. This is the first demonstration that an allosteric regulator can function in the context of a switch in G-protein-coupling specificity. There is no enhancement by PD81,723 of Gi-coupled A2A chimaeric receptors with A1 sequence replacing A2A sequence in the 3ICL. The results suggest that the recognition site for PD81,723 is on the A1 receptor and that the enhancer acts to directly stabilize the receptor to a conformational state capable of coupling with Gi or Gs.

scholarly journals Mechanistic insights into dopaminergic and serotonergic neurotransmission – concerted interactions with helices 5 and 6 drive the functional outcome

2021 ◽  
Author(s):  
Tomasz Maciej Stepniewski ◽  
Arturo Mancini ◽  
Richard Ågren ◽  
Mariona Torrens-Fontanals ◽  
Meriem Semache ◽  
...  
Keyword(s):  
Functional Outcome ◽  
Binding Site ◽  
G Protein ◽  
Functional Response ◽  
Receptor Binding ◽  
Transmembrane Helix ◽  
Receptor Binding Site ◽  
G Protein Coupling ◽  
Protein Coupling ◽  
Serotonergic Neurotransmission

Neurotransmitter contacts within the receptor binding site differentially contribute to the overall functional response: transmembrane helix (TM) 5 contacts promote G protein coupling whereas concerted TM5–TM6 contacts enhance β-arrestin recruitment.

G-protein coupling specificity of the human oxytocin receptor

2006 ◽  
Vol 27 (1) ◽  
pp. 123
Author(s):  
A. Reversi ◽  
C. Galés ◽  
M. Bouvier ◽  
B. Chini
Keyword(s):  
G Protein ◽  
Oxytocin Receptor ◽  
G Protein Coupling ◽  
Protein Coupling ◽  
Coupling Specificity
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