Figure 7.
EI24 (etoposide-induced protein 2.4 homolog) is the main connection between ubiquitin-mediated proteasomal system (UPS) and autophagy. The concerted action of ubiquitin ligases E1-E3 results in ubiquitination of target proteins to label for UPS-mediated degradation. Ubiquitin chain transfer to target proteins is catalyzed by the RING-domain E3 ligases. EI24, an autophagy-inducing protein, can cause autophagy-mediated degradation of RING-domain E3 ligases. Thick arrows represent main pathways, thin arrows—side pathways.