UBR1
Developmental stage
Expressed in fetal pancreas.
Domain
The RING-H2 zinc finger is an atypical RING finger with a His ligand in place of the fourth Cys of the classical motif (PubMed:20835242). The UBR-type zinc finger forms a pocket that mediates recognition of type 1 N-degrons (PubMed:20835242, PubMed:28392261). It exhibits preference for arginine in the first position (PubMed:20835242). It binds N-degrons with a methylated arginine in the first position (PubMed:28392261).
Function
E3 ubiquitin-protein ligase which is a component of the N-end rule pathway (PubMed:15548684, PubMed:16311597, PubMed:18162545, PubMed:20835242, PubMed:28392261). Recognizes and binds proteins bearing specific N-terminal residues that are destabilizing according to the N-end rule, leading to their ubiquitination and subsequent degradation (PubMed:18162545, PubMed:20835242, PubMed:28392261). Recognizes both type-1 and type-2 N-degrons, containing positively charged amino acids (Arg, Lys and His) and bulky and hydrophobic amino acids, respectively (PubMed:18162545). Does not ubiquitinate proteins that are acetylated at the N-terminus (PubMed:20835242). In contrast, it strongly binds methylated N-degrons (PubMed:28392261). Binds leucine and is a negative regulator of the leucine-mTOR signaling pathway, thereby controlling cell growth (PubMed:20298436).
Involvement in disease
Johanson-Blizzard syndrome
JBS
This disorder includes congenital exocrine pancreatic insufficiency, multiple malformations such as nasal wing aplasia, and intellectual disability. Pancreas of individuals with JBS do not express UBR1 and show intrauterine-onset destructive pancreatitis.
None
The disease is caused by variants affecting the gene represented in this entry.
Pathway
Protein modification; protein ubiquitination.
Sequence Similarities
Belongs to the E3 ubiquitin-protein ligase UBR1-like family.
Tissue Specificity
Broadly expressed, with highest levels in skeletal muscle, kidney and pancreas. Present in acinar cells of the pancreas (at protein level).
Cellular localization
- Cytoplasm
- Cytosol
Alternative names
E3 ubiquitin-protein ligase UBR1, N-recognin-1, Ubiquitin-protein ligase E3-alpha-1, Ubiquitin-protein ligase E3-alpha-I, UBR1