title: K11-linked polyubiquitination in cell cycle control revealed by a K11 linkage-specific antibody.
abstract: Polyubiquitination is a posttranslational modification where ubiquitin chains containing isopeptide bonds linking one of seven ubiquitin lysines with the C terminus of an adjoining ubiquitin are covalently attached to proteins. While functions of K48- and K63-linked polyubiquitin are understood, the role(s) of noncanonical K11-linked chains is less clear. A crystal structure of K11-linked diubiquitin demonstrates a distinct conformation from K48- or K63-linked diubiquitin. We engineered a K11 linkage-specific antibody and use it to demonstrate that K11 chains are highly upregulated in mitotic human cells precisely when substrates of the ubiquitin ligase anaphase-promoting complex (APC/C) are degraded. These chains increased with proteasomal inhibition, suggesting they act as degradation signals in vivo. Inhibition of the APC/C strongly impeded the formation of K11-linked chains, suggesting that a single ubiquitin ligase is the major source of mitotic K11-linked chains. Our results underscore the importance of K11-linked ubiquitin chains as critical regulators of mitotic protein degradation.
authors.affiliation: Department of Antibody Engineering, Genentech, Inc., South San Francisco, CA 94080, USA.
authors.forename: Marissa L
authors.initials: ML
authors.lastname: Matsumoto
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Wickliffe
authors.forename: Ken C
authors.initials: KC
authors.lastname: Dong
authors.forename: Christine
authors.initials: C
authors.lastname: Yu
authors.forename: Ivan
authors.initials: I
authors.lastname: Bosanac
authors.forename: Daisy
authors.initials: D
authors.lastname: Bustos
authors.forename: Lilian
authors.initials: L
authors.lastname: Phu
authors.forename: Donald S
authors.initials: DS
authors.lastname: Kirkpatrick
authors.forename: Sarah G
authors.initials: SG
authors.lastname: Hymowitz
authors.forename: Michael
authors.initials: M
authors.lastname: Rape
authors.forename: Robert F
authors.initials: RF
authors.lastname: Kelley
authors.forename: Vishva M
authors.initials: VM
authors.lastname: Dixit
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology*; D002453:Cell Cycle / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D011499:Protein Processing, Post-Translational / Q000502:physiology*; D025801:Ubiquitin / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*; D054875:Ubiquitination / Q000502:physiology*
chemical_list: D000911:Antibodies, Monoclonal; D025801:Ubiquitin; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome