Background: Membrane cholesterol dysregulation has been shown to alter the activity of the adenosine A2A receptor (A2AR), a G protein-coupled receptor, thereby implicating cholesterol levels in diseases such as Alzheimer's and Parkinson's. A limited number of A2AR crystal structures show the receptor interacting with cholesterol, as such molecular simulations are often used to predict cholesterol interaction sites.
Methods: Here, we use experimental methods to determine whether a specific interaction between amino acid side chains in the cholesterol consensus motif (CCM) of full length, wild-type human A2AR, and cholesterol modulates activity of the receptor by testing the effects of mutational changes on functional consequences, including ligand binding, G protein coupling, and downstream activation of cyclic AMP.
Results and conclusions: Our data, taken with previously published studies, support a model of receptor state-dependent binding between cholesterol and the CCM, whereby cholesterol facilitates both G protein coupling and downstream signaling of A2AR.
Keywords: CGS21680; Gαs; ZM241386; cholesterol; methyl β cyclodextrin; radioligand binding; surface plasmon resonance.