Photoreceptor signaling: when COP1 meets VPs.

How structurally distinct photoreceptors regulate evolutionarily diverse transcription factors to modulate common photoresponses is an intriguing question in plant biology. In this issue of The EMBO Journal, Lau et al demonstrate that COP1, the substrate receptor of E3 ubiquitin ligase CUL4COP 1- SPA s , interacts with the diverse VP motif-containing transcription factors and photoreceptors via its highly plastic WD40 domain. Light-activated photoreceptors increase their affinity to COP1 to outcompete the COP1-interacting transcription factors, allowing their accumulation and inducing photomorphogenic development of plants.