UASt regulatory sequences drive expression of an engineered kinase that is composed of the N-terminal kinase domain of Rok fused to the VHH(GFP4) nanobody. The lack of the C-terminal domain of Rok results in the kinase domain being constitutively active, and the presence of the VHH(GFP4) nanobody should target this active kinase domain to proteins that are tagged with GFP (the target of the VHH(GFP4) nanobody).