Cell-type-specific fluorescent tagging of endogenous target proteins reveals synaptic enrichment and dynamic regulations of dopamine receptors

Abstract

AbstractDopamine can play opposing physiological roles depending on the receptor subtype. In the fruit flyDrosophila melanogaster,Dop1R1andDop2Rencode the D1- and D2-like receptors, respectively, and are reported to oppositely regulate intracellular cAMP levels. Here, we profiled the expression and subcellular localization of endogenous Dop1R1 and Dop2R in specific cell types in the mushroom body circuit. For cell-type-specific visualization of endogenous proteins, we employed reconstitution of split-GFP tagged to the receptor proteins. We detected dopamine receptors at both presynaptic and postsynaptic sites in multiple cell types. Quantitative analysis revealed enrichment around the active zones, particularly for Dop2R. The presynaptic localization of Dop1R1 and Dop2R in dopamine neurons suggests dual feedback regulation as autoreceptors. Furthermore, we discovered a starvation-dependent, bidirectional modulation of the presynaptic receptor expression in the PAM and PPL1 clusters, two distinct subsets of dopamine neurons, suggesting regulation of appetitive behaviors. Our results highlight the significance of the co-expression of the two antagonizing dopamine receptors in the spatial and conditional regulation of dopamine responses in neurons.