Mechanism by which TRAF6 Participates in the Immune Regulation of Autoimmune Diseases and Cancer

Figure 2

The ubiquitination of TRAF6. Based on the data by Dainichi et al. [28]. Firstly, the E1 enzyme forms a thiol ester bond with a ubiquitin. Next, the activated ubiquitin is transferred to E2. Then, TRAF6 (the E3 enzyme) functions as a scaffold for the binding of both E2 and the target molecule, facilitating the transfer of ubiquitin from E2 to the target protein. Finally, TRAF6 mediates the addition of lysine-linked polyubiquitin chains to the substrates, commonly via K48-linked polyubiquitination or K63-linked polyubiquitination. The K48-linked polyubiquitin causes proteasomal degradation. The K63-linked polyubiquitin recruiting protein is used for further posttranslational modifications.