Skip to main content
. 2021 Jun 20;13(12):3079. doi: 10.3390/cancers13123079

Figure 1.

Figure 1

Overview of the ubiquitin-proteasome system (UPS). The E1, E2, E3 enzyme cascade results in the ubiquitination of a protein substrate. HECT and RBR-type E3 ligases perform a two-step ubiquitination, whereas RING E3s perform direct Ub transfer. K48-linked poly-ubiquitination results in proteasomal degradation, whereby the 19S proteasomal subunit removes Ub moieties prior to the substrate’s proteolytic degradation by the 26S subunit. DUBs can rescue substrate expression or alter cell signaling by removing Ub moieties. Ub, ubiquitin; HECT, Homologous to E6-AP carboxyl terminus; RBR, RING-between-RING; RING, really interesting new gene; DUB, deubiquitinase.