UBX protein domain

In molecular biology, the UBX protein domain is found in ubiquitin-regulatory proteins, which are members of the ubiquitination pathway, as well as a number of other ubiquitin-like proteins including FAF-1 (FAS-associated factor 1), the human Rep-8 reproduction protein and several hypothetical proteins from yeast. The function of the UBX domain is not known although the fragment of avian FAF-1 containing the UBX domain causes apoptosis of transfected cells.

UBX
solution structure of the ubx domain of kiaa0794 protein
Identifiers
Symbol	UBX
Pfam	PF00789
Pfam clan	CL0072
InterPro	IPR001012
SMART	UBX
SCOPe	1i42 / SUPFAM
Available protein structures: Pfam   structures / ECOD   PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Function

So far, as yet, no general function for the UBX domain has yet emerged.[1] Additionally, the absence of a carboxy-terminal di-glycine motif, however, indicates that UBX domains are not covalently attached to target proteins in a ubiquitin-like manner.[2]

Structure

The UBX domain comprises about 80 amino acid residues. They are distinct structural units defining a large family of proteins that often exhibit a modular domain architecture three-dimensional structures of UBX domains reveal a close structural relationship with ubiquitin despite the lack of significant sequence homology[2]

Homology

UBX domain is very similar to ubiquitin which gives us some indication of evolution. There are ubiquitin fusion which seem to be advantageous for ribosomal subunit folding.[2]

References

1. Buchberger A (May 2002). "From UBA to UBX: new words in the ubiquitin vocabulary". Trends in Cell Biology. 12 (5): 216–21. doi:10.1016/S0962-8924(02)02269-9. PMID 12062168.
2. Schuberth C, Buchberger A (August 2008). "UBX domain proteins: major regulators of the AAA ATPase Cdc48/p97". Cellular and Molecular Life Sciences. 65 (15): 2360–71. doi:10.1007/s00018-008-8072-8. PMID 18438607.

This article incorporates text from the public domain Pfam and InterPro: IPR001012