title: Mechanisms controlling the temporal degradation of Nek2A and Kif18A by the APC/C-Cdc20 complex.
abstract: The Anaphase Promoting Complex/Cyclosome (APC/C) in complex with its co-activator Cdc20 is responsible for targeting proteins for ubiquitin-mediated degradation during mitosis. The activity of APC/C-Cdc20 is inhibited during prometaphase by the Spindle Assembly Checkpoint (SAC) yet certain substrates escape this inhibition. Nek2A degradation during prometaphase depends on direct binding of Nek2A to the APC/C via a C-terminal MR dipeptide but whether this motif alone is sufficient is not clear. Here, we identify Kif18A as a novel APC/C-Cdc20 substrate and show that Kif18A degradation depends on a C-terminal LR motif. However in contrast to Nek2A, Kif18A is not degraded until anaphase showing that additional mechanisms contribute to Nek2A degradation. We find that dimerization via the leucine zipper, in combination with the MR motif, is required for stable Nek2A binding to and ubiquitination by the APC/C. Nek2A and the mitotic checkpoint complex (MCC) have an overlap in APC/C subunit requirements for binding and we propose that Nek2A binds with high affinity to apo-APC/C and is degraded by the pool of Cdc20 that avoids inhibition by the SAC.
authors.affiliation: The Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Garry G
authors.initials: GG
authors.lastname: Sedgwick
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Hayward
authors.forename: Barbara
authors.initials: B
authors.lastname: Di Fiore
authors.forename: Mercedes
authors.initials: M
authors.lastname: Pardo
authors.forename: Lu
authors.initials: L
authors.lastname: Yu
authors.forename: Jonathon
authors.initials: J
authors.lastname: Pines
authors.forename: Jakob
authors.initials: J
authors.lastname: Nilsson
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000378:metabolism*; D059566:M Phase Cell Cycle Checkpoints / Q000502:physiology; D000072379:NIMA-Related Kinases; D049468:Prometaphase / Q000502:physiology; D011485:Protein Binding; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D059748:Proteolysis; D013997:Time Factors; D014407:Tumor Cells, Cultured; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism / Q000502:physiology*
chemical_list: D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577440:CDC23 protein, human; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; C577488:CDC20 protein, human; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; C089441:NEK2 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases; C502735:KIF18A protein, human; D016547:Kinesins