UBA1 domain found in ubiquitin carboxyl-terminal hydrolase UBP5, UBP13 and similar proteins
UBP5, also called deubiquitinating enzyme 5, Isopeptidase T (IsoT), ubiquitin thioesterase 5, or ubiquitin-specific-processing protease 5, is a deubiquitinating enzyme largely responsible for the disassembly of the majority of unanchored polyubiquitin in the cell. Zinc is required for its catalytic activity. UBP5 contains four ubiquitin (Ub)-binding sites including an N-terminal zinc finger (ZnF) domain, a catalytic ubiquitin-specific processing protease (UBP) domain (catalytic C-box and H-box), and two ubiquitin-associated (UBA) domains. ZnF domain binds the proximal ubiquitin. UBP domain forms the active site. UBA domains are involved in binding linear or K48-linked polyubiquitin. UBP13, also called deubiquitinating enzyme 13, Isopeptidase T-3 (isoT3), ubiquitin thioesterase 13, or ubiquitin-specific-processing protease 13, is an ortholog of UBP5. It has similar domain architecture, but functions differently from USP5 in cellular deubiquitination processes. It exhibits a weak deubiquitinating activity preferring to Lys63-linked polyubiquitin in a non-activation manner. Moreover, the zinc finger (ZnF) domain of USP13 cannot bind to Ub. Its tandem UBA domains can bind with different types of diUb but preferentially with K63-linked.USP13 can also regulate the protein level of CD3delta in cells via its UBA domains. This model corresponds to the UBA1 domain.
Jiyao W et al.(2023). "The conserved domain database in 2023.",