Structural Determinants of the Dopamine Transporter Regulation Mediated by G Proteins.
Genoveva RojasIvana OrellanaRoberto Rosales-RojasJennie García-OlivaresJeffrey ComerAriela Vergara-JaquePublished in: Journal of chemical information and modeling (2020)
Dopamine clearance in the brain is controlled by the dopamine transporter (DAT), a protein residing in the plasma membrane, which drives reuptake of extracellular dopamine into presynaptic neurons. Studies have revealed that the βγ subunits of heterotrimeric G proteins modulate DAT function through a physical association with the C-terminal region of the transporter. Regulation of neurotransmitter transporters by Gβγ subunits is unprecedented in the literature; therefore, it is interesting to investigate the structural details of this particular protein-protein interaction. Here, we refined the crystal structure of the Drosophila melanogaster DAT (dDAT), modeling de novo the N- and C-terminal domains; subsequently, we used the full-length dDAT structure to generate a comparative model of human DAT (hDAT). Both proteins were assembled with Gβ1γ2 subunits employing protein-protein docking, and subsequent molecular dynamics simulations were run to identify the specific interactions governing the formation of the hDAT:Gβγ and dDAT:Gβγ complexes. A [L/F]R[Q/E]R sequence motif containing the residues R588 in hDAT and R587 in dDAT was found as key to bind the Gβγ subunits through electrostatic interactions with a cluster of negatively charged residues located at the top face of the Gβ subunit. Alterations of DAT function have been associated with multiple devastating neuropathological conditions; therefore, this work represents a step toward better understanding DAT regulation by signaling proteins, allowing us to predict therapeutic target regions.
Keyphrases
- protein protein
- molecular dynamics simulations
- small molecule
- uric acid
- drosophila melanogaster
- endothelial cells
- systematic review
- metabolic syndrome
- molecular docking
- physical activity
- prefrontal cortex
- white matter
- mental health
- resting state
- multiple sclerosis
- pluripotent stem cells
- induced pluripotent stem cells
- cerebral ischemia