GPR37 associates with the dopamine transporter to modulate dopamine uptake and behavioral responses to dopaminergic drugs

The orphan G protein-coupled receptor 37 (GPR37) is a substrate of parkin; its insoluble aggregates accumulate in brain samples of Parkinson's disease patients. We report here that GPR37 interacts with the dopamine transporter (DAT) and modulates DAT activity. GPR37 and DAT were found colocalized in mouse striatal presynaptic membranes and in transfected cells and their interaction was confirmed by coimmunoprecipitation assays. Gpr37-null mutant mice showed enhanced DAT-mediated dopamine uptake in striatal membrane samples, with a significant increase in the number of plasma membrane DAT molecules. The null mutant mice also exhibited a decrease in cocaine-induced locomotor activity and in catalepsy induced by dopamine receptor antagonists. These results reveal the specific role of GPR37, a putative peptidergic G protein-coupled receptor, in modulating the functional expression of DAT and the behavioral responses to dopaminergic drugs.