Ubiquitin-proteasome system components (UPS) (UPS)

The ubiquitination pathway, primarily known as the ubiquitin-proteasome system (UPS), is a fundamental cellular mechanism for regulated protein degradation and signal transduction (Source: Glickman & Ciechanover, 2002, Physiological Reviews). It involves a three-step enzymatic cascade: E1 (ubiquitin-activating), E2 (ubiquitin-conjugating), and E3 (ubiquitin-ligating) enzymes, which covalently attach ubiquitin to target substrates (Source: UniProt, "Ubiquitin-proteasome system"). This modification often serves as a signal for the 26S proteasome to degrade the protein, though it also regulates DNA repair, endocytosis, and immune signaling (Source: Mansour, 2018, Cell Communication and Signaling). Dysregulation of UPS components is central to the pathogenesis of various cancers, where it may lead to the degradation of tumor suppressors like p53, and neurodegenerative diseases such as Parkinson's, characterized by the failure to clear misfolded proteins (Source: Popovic et al., 2014, Nature Medicine). Therapeutic targeting of the UPS has yielded significant clinical success, notably with proteasome inhibitors like bortezomib for multiple myeloma and E3 ligase modulators like lenalidomide (Source: FDA, 2003, 2005). Emerging modalities such as Proteolysis Targeting Chimeras (PROTACs) further exploit this pathway to achieve targeted protein degradation of previously "undruggable" targets (Source: Arvinas, 2023).

Other names

Ubiquitination pathway componentsUbiquitin-proteasome systemUPSUbiquitin-mediated proteolysis pathwayProtein ubiquitination pathway

Proteasome inhibition, E3 ligase modulation (molecular glues), Targeted protein degradation (PROTACs), Deubiquitinase (DUB) inhibition