UAS regulatory sequences drive expression of 'paAIP2', a genetically encoded light-inducible inhibitor of CaMKII kinase activity. paAIP2 is composed of the autocamtide-2 related inhibitory peptide 2 (AIP2) sequence (KKKLRRQEAFDAL), tagged at the N-terminal end with the light-sensitive Tag:AsLOV2 domain. In the absence of photoactivation, the Tag:AsLOV2 domain sterically blocks the action of AIP2. Upon illumination with blue light, the Tag:AsLOV2 domain undergoes a conformational change that allows the AIP2 sequence to act as a CaMKII kinase inhibitor. The conformational change is reversible, so that if the blue light illumination is removed, the Tag:AsLOV2 domain spontaneously reverts to the conformation that sterically blocks AIP2 (details from PMID:28318784).