UASt sequences regulate expression of a fusion protein composed of the Tag:TM(hPDGFRB) transmembrane domain, the CIBN(ΔNLS)::N-TEV split protease fragment (with a nuclear export signal in the linker between the CIBN(ΔNLS) and N-TEV portions), Tag:AsLOV2(BLITz-1) (a TEVp protease target site that is inaccessible in the dark), mCherry, and the intracellular domain of N (amino acids 1766-2703) into which a Tag:AsLOV2 domain has been introduced near the N-terminal end (between residues 1768-1769, six residues upstream of the conserved ΦWΦP motif). In the dark, the presence of the Tag:AsLOV2 domain masks the ΦWΦP motif (this prevents the uncleaved protein sequestering Su(H) protein, which is seen if the Tag:AsLOV2 domain is not present). Upon illumination with blue light, both the Tag:AsLOV2(BLITz-1) and Tag:AsLOV2 peptides undergo a conformational change; the first results in the TEVp protease target site becoming accessible, while the second unmasks the ΦWΦP motif in the N intracellular domain. In addition, if the transgene is co-expressed with a source of the CRY2(PHR)::C-TEV split protease fragment, light exposure also allows the CIBN(ΔNLS)::N-TEV and CRY2(PHR)::C-TEV peptides to associate and reconstitute a functional TEVp protease, which can cleave the now accessible TEVp protease target site, releasing a mCherry-Tag:AsLOV2-tagged N intracellular domain.