Dis-RUP for COP1 Role-Switch under UV-B Light.
It is well known that E3 ubiquitin ligase COP1 is a negative regulator of plant photomorphogenesis. However, COP1 acts as a positive regulator under UV-B light. A recent study (Ren et al. Proc. Natl. Acad. Sci. U. S. A. 2019;116:4722-4731) proposes a two-step protein degradation model to explain how COP1 switches its role in response to UV-B light.