UAS regulatory sequences and a minimal Hsp70 promoter (derived from the pUASTLOTattB vector) are fused upstream of a fusion protein that consists of the GFP-binding VHH(GFP4) nanobody, the Tag:M(mCd8a) transmembrane domain and the mCherry fluorescent tag. The VHH(GFP4) nanobody is extracellular, allowing it to trap any GFP-tagged extracellular protein, while the mCherry tag is located in the cytosol. (Generated by P1cre-mediated excision of the lexAop regulatory sequences present in Zzzz\vhhGFP4lexAop.UAS.morphotrap.ext.mCherry).