The name of this superfamily has been modified since the most recent official CATH+ release (v4_3_0). At the point of the last release, this superfamily was named:

Ubiquitin fusion degradation protein UFD1, N-terminal domain

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.

Superfamily: Ubiquitin fusion degradation protein UFD1, N-terminal domain

Post-translational ubiquitin-protein conjugates are recognised for degradation by the ubiquitin fusion degradation (UFD) pathway. Several proteins involved in this pathway have been identified PMID:7615550. This superfamily includes UFD1, a 40kD protein that is essential for vegetative cell viability PMID:7615550. The human UFD1 gene is expressed at high levels during embryogenesis, especially in the eyes and in the inner ear primordia and is thought to be important in the determination of ectoderm-derived structures, including neural crest cells. In addition, this gene is deleted in the CATCH-22 (cardiac defects, abnormal facies, thymic hypoplasia, cleft palate and hypocalcaemia with deletions on chromosome 22) syndrome. This clinical syndrome is associated with a variety of developmental defects, all characterised by microdeletions on 22q11.2. Two such developmental defects are the DiGeorge syndrome OMIM:188400 and the velo-cardio-facial syndrome OMIM:145410. Several of the abnormalities associated with these conditions are thought to be due to defective neural crest cell differentiation.


Ufd1 is part of the Ufd1-Npl4 complex that functions as the substrate-recruiting cofactor for Cdc48 segregase. The Cdc48-Ufd1-Npl4 complex is involved in degradation of misfolded ER proteins PMID:20206597. The Ufd1-Npl4 complex has been found to recruit Cdc48 to ubiquitylated CMG (Cdc45-MCM-GINS) helicase at the end of chromosome replication, thereby driving the disassembly reaction PMID:28355556. In humans, Npl4-Ufd1 acts as a cofactor in reducing antiviral innate immune responses by facilitating proteasomal degradation of RIG-I (a viral RNA sensor) PMID:26471729.


GO Diversity

Unique GO annotations
49 Unique GO terms

EC Diversity

Unique EC annotations
0 Unique EC terms

Species Diversity

Unique species annotations
1492 Unique species

Sequence/Structure Diversity

Overview of the sequence / structure diversity of this superfamily compared to other superfamilies in CATH. Click on the chart to view the data in more detail.

Superfamily Summary

A general summary of information for this superfamily.
Domains: 2
Domain clusters (>95% seq id): 2
Domain clusters (>35% seq id): 1
Unique PDBs: 2
Structural Clusters (5A): 1
Structural Clusters (9A): 1
FunFam Clusters: 5
Unique EC:
Unique GO: 49
Unique Species: 1492