Fig. 1
From: The emerging role of SPOP protein in tumorigenesis and cancer therapy
UPS-mediated protein degradation. Ubiquitin is activated by the E1 enzyme in an ATP-dependent fashion. Then, the active form of ubiquitin is conjugated to the E2 enzyme, after which it is transferred to a specific target substrate depending on the E3 ligase involved. E3 ligases are crucial for determining the substrate specificity for degradation