Interaction of the ring finger-related U-box motif of a nuclear dot protein with ubiquitin-conjugating enzymes.
The U-box domain has been suggested to be a modified RING finger motif where the metal-coordinating cysteines and histidines have been replaced with other amino acids. Known U-box-containing proteins have been implicated in the ubiquitin/proteasome system. In a search for proteins interacting with the ubiquitin-conjugating enzyme UbcM4/UbcH7, we have identified ... a novel U-box containing protein, termed UIP5, that is exclusively found in the nucleus as part of a nuclear dot-like structure. Interaction between UbcM4 and UIP5 was observed in vivo and in vitro with bacterially expressed proteins. In addition to UbcM4, several other ubiquitin-conjugating enzymes (E2s) that share the same sequence within the L1 loop bind to UIP5. Mutational analysis showed that the U-box, like the RING finger in other proteins, forms the physical basis for the interaction with E2 enzymes. Further support for the structural similarity between U-box and RING finger comes from the observation that, in both cases, the same regions within the UbcM4 molecule are required for interaction. Our results establish at the molecular level a link between the U-box and the ubiquitin conjugating system and strongly suggest that proteins containing U-box domains are functionally closely related to RING finger proteins.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Amino Acid Motifs, Amino Acid Sequence, Animals, Antigens, Nuclear, Autoantigens, Blotting, Northern, Carrier Proteins, Cell Line, Cell Nucleus, Cysteine, Cysteine Endopeptidases, Hela Cells, Histidine, Humans, Immunohistochemistry, Ligases, Mice, Microscopy, Fluorescence, Molecular Sequence Data, Multienzyme Complexes, Nuclear Proteins, Plasmids, Proteasome Endopeptidase Complex, Protein Binding, Protein Structure, Tertiary, RNA, Recombinant Proteins, Sequence Homology, Amino Acid, Tissue Distribution, Transfection, Two-Hybrid System Techniques, Ubiquitin-Conjugating Enzymes, Ubiquitins
Adaptor Proteins, Signal Transducing, Amino Acid Motifs, Amino Acid Sequence, Animals, Antigens, Nuclear, Autoantigens, Blotting, Northern, Carrier Proteins, Cell Line, Cell Nucleus, Cysteine, Cysteine Endopeptidases, Hela Cells, Histidine, Humans, Immunohistochemistry, Ligases, Mice, Microscopy, Fluorescence, Molecular Sequence Data, Multienzyme Complexes, Nuclear Proteins, Plasmids, Proteasome Endopeptidase Complex, Protein Binding, Protein Structure, Tertiary, RNA, Recombinant Proteins, Sequence Homology, Amino Acid, Tissue Distribution, Transfection, Two-Hybrid System Techniques, Ubiquitin-Conjugating Enzymes, Ubiquitins
J. Biol. Chem.
Date: Jun. 01, 2001
PubMed ID: 11274149
View in: Pubmed Google Scholar
Download Curated Data For This Publication
11500
Switch View:
- Interactions 5