New insights into the model of dopamine D-1 receptor and G-proteins interactions

摘要

The details of the interaction between G-proteins and the GPCRs have been subjected to extensive investigation with structural and functional assays, but still many fundamental questions regarding this macromolecular assembly and its mechanism remain unanswered. in the context of current structural data we investigated interactions of dopamine D-1 receptor with cognate G-proteins (Gas) in living cells, emphasizing the prevalence of preassembled D-1-G-protein complexes. We also tested the effect of D-1 receptor presence on the dynamics of Gas and G alpha i(3) in the cellular plasma membrane. Using fluorescence resonance energy transfer (FRET) detected by fluorescence lifetime imaging microscopy (FLIM) or fluorescence recovery after photobleaching (FRAP) microscopy, we did not detect constitutive preassociated complex between D-1 receptor and G-protein in the absence of receptor activation. Our work suggests that D-1 receptor alters the distribution of Gas and G alpha i(3) subunits inside the membrane. We also find that non-activated D-1 receptor and Gas or G alpha i(3) are present in the cell membrane within the same membrane microdomains in the proximity of about 9-10 nm. (C) 2014 Elsevier B.V. All rights reserved.