This entry includes a group of ubiquitinyl hydrolases, also known as ubiquitin carboxyl-terminal hydrolases, including USP13 and USP5 from animals, and Ubp14 from plants and fungi. Budding yeast Ubp14 may facilitate proteolysis by preventing unanchored ubiquitin chains from competitively inhibiting polyubiquitin-substrate binding to the 26S proteasome [, ].USP5 recognizes and recycles the unanchored polyUb chain to keep the free Ub pool stable []. USP13 is an ortholog of USP5. However, unlike USP5, USP13 exhibits a weak deubiquitinating activity preferring to Lys63-linked polyubiquitin (K63-polyUb) in a non-activation manner. It may function differently from USP5 in cellular deubiquitination processes [].
This entry represents a group of ubiquitin domain-containing proteins, including UBTD1 and UBTD2. UBTD1 regulates cellular senescence through a positive feedback loop with TP53 []. UBTD1 and UBE2D (E2 ubiquitin conjugating enzyme) have been shown to form a stable, stoichiometric complex []. UBTD2, also known as DC-UbP, interacts with deubiquitinating enzyme USP5 and the Ub-activating enzyme UbE1 [].
