InterPro domain: IPR039164

This entry represents a group of E3 ubiquitin-protein ligases, including UBR1, UBR2 and UBR3. They are part of the N-end rule pathway [ 1 ]. They recognize and bind to proteins bearing specific N-terminal residues, leading to their ubiquitination and subsequent degradation [ 2 , 3 ].

The UBR1 protein was shown to bind specifically to proteins bearing N-terminalresidues that are destabilising according to the N-end rule, but not tootherwise identical proteins bearing stabilising N-terminal residues [ 4 ]. UBR1 contains an N-terminal conserved region (the UBR-type zinc finger) which is also found in various proteins implicated in N-degron recognition [ 5 ].

1. Biochemical and genetic studies of UBR3, a ubiquitin ligase with a function in olfactory and other sensory systems. J. Biol. Chem. 282, 18510-20
2. Pri sORF peptides induce selective proteasome-mediated protein processing. Science 349, 1356-8
3. Ubr3, a Novel Modulator of Hh Signaling Affects the Degradation of Costal-2 and Kif7 through Poly-ubiquitination. PLoS Genet. 12, e1006054
4. The E2-E3 interaction in the N-end rule pathway: the RING-H2 finger of E3 is required for the synthesis of multiubiquitin chain. EMBO J. 18, 6832-44
5. A family of mammalian E3 ubiquitin ligases that contain the UBR box motif and recognize N-degrons. Mol. Cell. Biol. 25, 7120-36