title: UBE2S drives elongation of K11-linked ubiquitin chains by the anaphase-promoting complex.
abstract: The Anaphase-Promoting Complex (APC) is an E3 ubiquitin ligase that regulates mitosis and G1 by sequentially targeting cell-cycle regulators for ubiquitination and proteasomal degradation. The mechanism of ubiquitin chain formation by APC and the resultant chain topology remains controversial. By using a single-lysine APC substrate to dissect the topology of ubiquitinated substrates, we find that APC-catalyzed ubiquitination has an intrinsic preference for the K11 linkage of ubiquitin that is essential for substrate degradation. K11 specificity is determined by an E2 enzyme, UBE2S/E2-EPF, that elongates ubiquitin chains after the substrates are pre-ubiquitinated by UbcH10 or UbcH5. UBE2S copurifies with APC; dominant-negative Ube2S slows down APC substrate degradation in functional cell-cycle extracts. We propose that Ube2S is a critical, unique component of the APC ubiquitination pathway.
authors.affiliation: Department of Systems Biology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.
authors.forename: Tao
authors.initials: T
authors.lastname: Wu
authors.forename: Yifat
authors.initials: Y
authors.lastname: Merbl
authors.forename: Ying
authors.initials: Y
authors.lastname: Huo
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Gallop
authors.forename: Amit
authors.initials: A
authors.lastname: Tzur
authors.forename: Marc W
authors.initials: MW
authors.lastname: Kirschner
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D055162:Biocatalysis; D002453:Cell Cycle; D006367:HeLa Cells; D006801:Humans; D008239:Lysine / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009363:Neoplasm Proteins / Q000378:metabolism; D011485:Protein Binding; D064249:Securin; D013379:Substrate Specificity; D025801:Ubiquitin / Q000378:metabolism*; D044763:Ubiquitin-Conjugating Enzymes / Q000235:genetics / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*
chemical_list: D009363:Neoplasm Proteins; D064249:Securin; D025801:Ubiquitin; C544962:Ube2S protein, human; D044763:Ubiquitin-Conjugating Enzymes; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D008239:Lysine