[Retracted] The Role of Posttranslational Modification and Mitochondrial Quality Control in Cardiovascular Diseases

Figure 2

The process of protein ubiquitination. First, the inactive ubiquitin (Ub) molecule is activated under the catalysis of DUBs. Under the action of 1 molecule of ATP, Ub binds to an E1 activating enzyme; then, the E2 conjugating enzyme replaces E1 and connects to Ub. Next, E2 presents Ub to the E3 ligase, and the E3 ligase binds specifically to the target protein. The above steps are repeated until the target protein binds more than 4 Ub molecules to form a Ub chain. Then, the 26S proteasome recognizes the Ub chain and places the target protein in its own barrel. Finally, the target protein is degraded into small fragments by ATP consumption, and the Ub molecule is restored for release.