An α-tubulin promoter drives expression of a fusion protein which consists of Hsap\HRH2 fused at its C-terminus to Scer\GAL4, with the two coding sequences interposed by a TEV protease cleavage site (Tag:CS(TEVp)). The presence of Hsap\HRH2 (a G protein-coupled receptor) tethers the fusion protein to the cell membrane. The GAL4 driver can be released from the membrane by cleavage of the Tag:CS(TEVp) site with the TEVp protease.