UBA Domain |
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Class:Ubiquitin processes |
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Structure:
NMR data reveals that the UBA domains of the human homologue of yeast Rad23A (HHR23A) form three-helix bundles with a hydrophobic core that stabilizes the protein. These domains also possess a conserved surface patch of hydrophobic amino acids that likely interact with hydrophobic regions of ubiquitin and other target proteins.
Structure Reference: Mueller, TD. and Feigon, J. (2002) J. Mol. Biol. 319(5): 1243-1255. PDB: 1IFY.
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Domain binding and function: The ubiquitin-associated (UBA) domain is an approximately 40 amino acid motif that was first recognized in proteins associated with ubiquitination but is also found in proteins involved in DNA nucleotide excision-repair and other proteins. UBA domains have been shown to bind mono-, di-, tri-, and tetra-ubiquitin in vitro but appear to bind to polyubiquitin with a higher affinity and it is thought that polyubiquitinated proteins represent the true in vivo binding substrates. As well, some UBA domains appear to homo and heterodimerize and to bind other substrates. Functionally, the UBA domain has been proposed to limit ubiquitin chain elongation and to target ubiquitinated proteins to the 26S proteasome for degradation.
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Examples of Proteins:
UBA Domain Proteins |
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Binding Partners |
HHR23A |  |
mono and polyubiquitin
Rad23 (homodimerization)
HHR23A (heterodimerization)
HIV Vpr
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c-Cbl |  |
unknown
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HIP-2 E2 |  |
unknown
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Referenced in part on Cell Signaling Technology Website, Reference Section on Protein Domains. We gratefully acknowledge the following contributors:
Piers Nash1, Dan Lin3, Kathleen Binns2, Clark Wells2, Rob Ingham2, Terry Kubiseski2, Bernard Liu1, Matt Smith2,3, Ivan Blasutig2,3, Maria Sierra1, Caesar Lim2,3, Michael Arc1, Jim Fawcett2 and Tony Pawson2,3.
1. Ben May Institute for Cancer Research, The University of Chicago, Chicago, Illinois, 60637, USA
2. Program in Molecular Biology and Cancer, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
3. Department of Molecular and Medical Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
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