FIGURE 1.

Principle of photoPROTACs. Upon irradiation with an appropriate wavelength of light, photoPROTACs are activated. (Photoswitchable PROTACs undergo conformation change into active PROTACs, and photocaged PROTACs are induced to dissociate from the caging group to expose active functional groups.) Subsequently, the activated PROTACs bind the POI and recruit relevant E3 ligase for ubiquitination. Ultimately, polyubiquitinated POIs are degraded via the proteasome pathway. Active PROTACs separate from the polyubiquitinated POIs and participate in the subsequent catalytic cycle. Gray rectangle represents the caging group; yellow linker signifies the photoswitcher element; The black linker conjugates the cyan triangle with the red circle and presents the active PROTAC. POI, protein of interest; PROTAC, proteolysis-targeting chimera.