title: Multiple mechanisms determine the order of APC/C substrate degradation in mitosis.
abstract: The ubiquitin protein ligase anaphase-promoting complex or cyclosome (APC/C) controls mitosis by promoting ordered degradation of securin, cyclins, and other proteins. The mechanisms underlying the timing of APC/C substrate degradation are poorly understood. We explored these mechanisms using quantitative fluorescence microscopy of GFP-tagged APC/C(Cdc20) substrates in living budding yeast cells. Degradation of the S cyclin, Clb5, begins early in mitosis, followed 6 min later by the degradation of securin and Dbf4. Anaphase begins when less than half of securin is degraded. The spindle assembly checkpoint delays the onset of Clb5 degradation but does not influence securin degradation. Early Clb5 degradation depends on its interaction with the Cdk1-Cks1 complex and the presence of a Cdc20-binding "ABBA motif" in its N-terminal region. The degradation of securin and Dbf4 is delayed by Cdk1-dependent phosphorylation near their Cdc20-binding sites. Thus, a remarkably diverse array of mechanisms generates robust ordering of APC/C(Cdc20) substrate destruction.
authors.affiliation: Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158.
authors.forename: Dan
authors.initials: D
authors.lastname: Lu
authors.affiliation: Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158.
authors.forename: Jennifer Y
authors.initials: JY
authors.lastname: Hsiao
authors.affiliation: Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158.
authors.forename: Norman E
authors.initials: NE
authors.lastname: Davey
authors.affiliation: Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158.
authors.forename: Vanessa A
authors.initials: VA
authors.lastname: Van Voorhis
authors.affiliation: Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Foster
authors.affiliation: Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China david.morgan@ucsf.edu tangc@pku.edu.cn.
authors.forename: Chao
authors.initials: C
authors.lastname: Tang
authors.affiliation: Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158 david.morgan@ucsf.edu tangc@pku.edu.cn.
authors.forename: David O
authors.initials: DO
authors.lastname: Morgan
mesh_terms: D020816:Amino Acid Motifs; D000705:Anaphase; D064173:Anaphase-Promoting Complex-Cyclosome / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D016203:CDC2 Protein Kinase / Q000378:metabolism; D064199:Cdc20 Proteins / Q000235:genetics; D018797:Cell Cycle Proteins / Q000378:metabolism*; D019926:Cyclin B / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics; D059566:M Phase Cell Cycle Checkpoints; D008938:Mitosis / Q000235:genetics*; D015739:Nocodazole / Q000494:pharmacology; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D064249:Securin / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism; D050257:Tubulin Modulators / Q000494:pharmacology
chemical_list: C577495:CDC20 protein, S cerevisiae; C076558:CLB5 protein, S cerevisiae; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; D019926:Cyclin B; C088096:Dbf4 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D064249:Securin; D050257:Tubulin Modulators; D049452:Green Fluorescent Proteins; D064173:Anaphase-Promoting Complex-Cyclosome; D016203:CDC2 Protein Kinase; D015739:Nocodazole