Phytochrome
Protein DomainPhytochromes are red/far-red light-sensing photoreceptor protein domains that serve as source scaffolds for engineered fluorescent proteins, biosensors, and optogenetic tools. In native signaling, photoactive phytochromes regulate transcription through direct interaction with PHYTOCHROME INTERACTING FACTOR proteins and through light-dependent inactivation of the COP1/SPA E3 ligase complex.