A serine point mutation in the adenosine A2AR C-terminal tail reduces receptor heteromerization and allosteric modulation of the dopamine D2R

Evidence exists that the adenosine receptor A2AR and the dopamine receptor D2R form constitutive heteromers in living cells. Mass spectrometry and pull-down data showed that an arginine-rich domain of the D2R third intracellular loop binds via electrostatic interactions to a specific motif of the A2AR C-terminal tail. It has been indicated that the phosphorylated serine 374 might represent an important residue in this motif. In the present study, it was found that a point mutation of serine 374 to alanine reduced the A2AR ability to interact with D2R. Also, this point mutation abolished the A2AR-mediated inhibition of both the D2R high affinity agonist binding and signaling. These results point to a key role of serine 374 in the A2AR-D2R interface. All together these results indicate that by targeting A2AR serine 374 it will be possible to allosterically modulate A2AR-D2R function, thus representing a new approach for therapeutically modulate D2R function.