A novel UbcH10-binding protein facilitates the ubiquitinylation of cyclin B in vitro.
UbcH10 is known to act as a ubiquitin-conjugating enzyme (E2) for anaphase-promoting complex/cyclosome. Since some E2s support different ubiquitin ligases (E3), it is possible that UbcH10 interacts with other proteins. We cloned a novel protein named H10BH by using a yeast two-hybrid screening method with UbcH10 as bait. The carboxyl terminus of H10BH showed a weak homology to the HECT (homologous to E6-AP carboxyl terminus) domain, which is conserved in one of the families of E3. H10BH bound UbcH10, and the amino acid sequence between 235 and 257 was necessary for this binding. H10BH showed a self-ubiquitinylation activity in a HECT-like sequence-dependent manner. The carboxyl terminal half (amino acids 188-389) showed stronger activity than the full-length H10BH. Furthermore, the carboxyl terminal half of H10BH was able to bind cyclin B and ubiquitinylate cyclin B in vitro. These results suggest that H10BH functions as an E3 using UbcH10 for its E2.
Kobirumaki
Fuyu
F
Division of Molecular Life Science, School of Life Science, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392.
Miyauchi
Yasuhiro
Y
Fukami
Kiyoko
K
Tanaka
Hirofumi
H
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D019926:Cyclin B / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques; D025801:Ubiquitin / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases
D002352:Carrier Proteins; D019926:Cyclin B; D025801:Ubiquitin; C105156:UBE2C protein, human; D044763:Ubiquitin-Conjugating Enzymes; C502845:UBE3D protein, human; D044767:Ubiquitin-Protein Ligases