UAS regulatory sequences drive expression of the put coding sequence, mutated so that a seven amino acid stretch in the basolateral targeting (BLT) juxtamembrane sequence (FNEIPTE, containing amino acids conserved in insects) has been mutated to Ala residues (the coding sequence also contains a K185L amino acid change from a cloning scar, due to insertion of a PstI site in the coding sequence). The coding sequence is tagged with Tag:HA.