title: A giant ubiquitin-conjugating enzyme related to IAP apoptosis inhibitors.
abstract: Ubiquitin-conjugating enzymes (UBC) catalyze the covalent attachment of ubiquitin to target proteins and are distinguished by the presence of a UBC domain required for catalysis. Previously identified members of this enzyme family are small proteins and function primarily in selective proteolysis pathways. Here we describe BRUCE (BIR repeat containing ubiquitin-conjugating enzyme), a giant (528-kD) ubiquitin-conjugating enzyme from mice. BRUCE is membrane associated and localizes to the Golgi compartment and the vesicular system. Remarkably, in addition to being an active ubiquitin-conjugating enzyme, BRUCE bears a baculovirus inhibitor of apoptosis repeat (BIR) motif, which to this date has been exclusively found in apoptosis inhibitors of the IAP-related protein family. The BIR motifs of IAP proteins are indispensable for their anti-cell death activity and are thought to function through protein-protein interaction. This suggests that BRUCE may combine properties of IAP-like proteins and ubiquitin-conjugating enzymes and indicates that the family of IAP-like proteins is structurally and functionally more diverse than previously expected.
authors.affiliation: Friedrich-Miescher-Laboratorium der Max-Planck-Gesellschaft, 72076 Tübingen, Germany.
authors.forename: H P
authors.initials: HP
authors.lastname: Hauser
authors.forename: M
authors.initials: M
authors.lastname: Bardroff
authors.forename: G
authors.initials: G
authors.lastname: Pyrowolakis
authors.forename: S
authors.initials: S
authors.lastname: Jentsch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary; D015870:Gene Expression; D051034:Inhibitor of Apoptosis Proteins; D007425:Intracellular Membranes / Q000378:metabolism; D008025:Ligases / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D051379:Mice; D008969:Molecular Sequence Data; D016716:PC12 Cells; D051381:Rats; D017386:Sequence Homology, Amino Acid; D044763:Ubiquitin-Conjugating Enzymes; D014764:Viral Proteins
chemical_list: D018076:DNA, Complementary; D051034:Inhibitor of Apoptosis Proteins; D008565:Membrane Proteins; D014764:Viral Proteins; C086430:inhibitor of apoptosis, Nucleopolyhedrovirus; D044763:Ubiquitin-Conjugating Enzymes; D008025:Ligases; C112991:ubiquitin-conjugating enzyme BRUCE