This is a graphical illustration of the iTango system. DRD2-V2 tail (C-terminus of V2 vasopression receptor)-CIBN-AsLOV2-tTA functions as a main platform. Two more modules cooperate together to cleave TEVseq by reacting to either light or ligand. DRD2 activation by an agonist will lead to beta-Arrestin2-TEV-N fusion protein translocate and bind to V2 tail. The other TEV-C will be recruited by blue light via CRY2PHRCIBN binding. When all iTango modules combine, released tTA will translocate to the nucleus to cause gene expression.