title: Ubch9 conjugates SUMO but not ubiquitin.
abstract: Ubiquitin conjugating enzymes participate in the thioester cascade that leads to protein ubiquitination. Although Ubc9 is homologous to E2 ubiquitin conjugating enzymes we have shown that it is unable to form a thioester with ubiquitin, but can form a thioester with the small ubiquitin-like protein SUMO. Thus Ubc9 is a SUMO conjugating enzyme rather than a ubiquitin conjugating enzyme. Transacetylation of Ubc9 by SUMO is not mediated by the E1 ubiquitin activating enzyme, but by a distinct enzymatic activity. SUMO conjugation to target proteins is mediated by a different, but parallel pathway to ubiquitination.
authors.affiliation: School of Biomedical Science, University of St. Andrews, Fife, UK.
authors.forename: J M
authors.initials: JM
authors.lastname: Desterro
authors.forename: J
authors.initials: J
authors.lastname: Thomson
authors.forename: R T
authors.initials: RT
authors.lastname: Hay
mesh_terms: D000107:Acetylation; D003001:Cloning, Molecular; D017931:DNA Primers; D015723:Gene Library; D005982:Glutathione Transferase; D006801:Humans; D008025:Ligases / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D025842:SUMO-1 Protein; D012441:Saccharomyces cerevisiae; D013379:Substrate Specificity; D044763:Ubiquitin-Conjugating Enzymes; D014452:Ubiquitins / Q000378:metabolism*; D000098843:Ubiquitin-Conjugating Enzyme UBC9
chemical_list: D017931:DNA Primers; D011993:Recombinant Fusion Proteins; D025842:SUMO-1 Protein; D014452:Ubiquitins; D044763:Ubiquitin-Conjugating Enzymes; D005982:Glutathione Transferase; D008025:Ligases; D000098843:Ubiquitin-Conjugating Enzyme UBC9