UAS regulatory sequences drive expression of a fusion protein composed of the Tag:SS(wg) signal peptide, a Tag:HA epitope, the FAPα2 fluorogen-activating peptide, a Tag:MYC epitope, a transmembrane domain (Tag:TM(hPDGFRB)) and the carboxy terminus of Sh. The configuration of the fusion protein results in the FAPα2 sequence and epitope tags being extracellular, while the Sh sequence is intracellular (as in the endogenous Sh protein).