UAS regulatory sequences and a minimal Hsp70 promoter (derived from the pUASTLOTattB vector) are fused upstream of a fusion protein that consists of the scFv(antiHA-X15F11) single-chain antibody, a transmembrane domain (Tag:M(mCd8a)) and the mCherry fluorescent tag. The scFv(antiHA-X15F11) single-chain antibody is extracellular, allowing it to trap any Tag:HA-tagged extracellular protein, while the mCherry tag is located in the cytosol. (Generated by P1cre-mediated excision of the lexAop regulatory sequences present in P{lexAop-UAS-GrabHA.ext.mCh}).