UASt sequences regulate expression of 'optoDop1R2[V2]', an engineered dopamine receptor that can be activated by light (the formation of the functional receptor also requires the presence of cis-retinal, which must be provided by feeding in Drosophila). 'optoDop1R2[V2]' is a chimeric protein that is based on the light-sensitive Btau\RHO G protein-coupled receptor (GPCR), in which Btau\RHO segments containing G protein binding sites have been exchanged for those of Dop1R2; in the V2 version of optoDop1R2, intracellular loops 2 and 3 (together with proximal transmembrane residues) and the C-terminal region have been exchanged for Dop1R2 sequence.
