UASp regulatory sequences drive expression of the cytoplasmic domain of htl, tagged at the N-terminal end with the Tag:Myr(Src42A) membrane localization signal and at the C-terminal end with CRY2(PHR) and with mCherry. In response to blue light of 488nm, oligomerization of the protein occurs (due to the presence of the the CRY2(PHR)-mCherry portion). This allows the active htl receptor (a dimer) to be induced in a light-dependent manner, independent of ligand.