Fig. 2
From: Ubiquitin-specific protease 28: the decipherment of its dual roles in cancer development
Schematic introduction of ubiquitination and deubiquitination. Sequential catalyzation caused by E1, E2 and E3 contributes to ubiquitin activation, ubiquitin conjugation and ubiquitin ligation respectively, leading to the ubiquitination of substrates. Ubiquitination of substrates results in the proteasomal degradation of themselves. While if deubiquitinases such as USP28 exist, the ubiquitin chains of substrates can be removed and the interaction between the enzyme and the substrates is realized directly or indirectly (with the help of E3 ligases)