title: A novel motif governs APC-dependent degradation of Drosophila ORC1 in vivo.
abstract: Regulated degradation plays a key role in setting the level of many factors that govern cell cycle progression. In Drosophila, the largest subunit of the origin recognition complex protein 1 (ORC1) is degraded at the end of M phase and throughout much of G1 by anaphase-promoting complexes (APC) activated by Fzr/Cdh1. We show here that none of the previously identified APC motifs targets ORC1 for degradation. Instead, a novel sequence, the O-box, is necessary and sufficient to direct Fzr/Cdh1-dependent polyubiquitylation in vitro and degradation in vivo. The O-box is similar to but distinct from the well characterized D-box. Finally, we show that O-box motifs in two other proteins, Drosophila Abnormal Spindle and Schizosaccharomyces pombe Cut2, contribute to Cdh1-dependent polyubiquitylation in vitro, suggesting that the O-box may mediate degradation of a variety of cell cycle factors.
authors.affiliation: Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: Marito
authors.initials: M
authors.lastname: Araki
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yu
authors.forename: Maki
authors.initials: M
authors.lastname: Asano
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D016193:G1 Phase / Q000502:physiology*; D051738:Origin Recognition Complex / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational / Q000502:physiology; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D064249:Securin; D025801:Ubiquitin / Q000378:metabolism; D043743:Ubiquitin-Protein Ligase Complexes / Q000235:genetics / Q000378:metabolism*
chemical_list: D064200:Cdh1 Proteins; D018797:Cell Cycle Proteins; C103136:Cut2 protein, S pombe; D029721:Drosophila Proteins; C497213:Orc1 protein, Drosophila; D051738:Origin Recognition Complex; D029702:Schizosaccharomyces pombe Proteins; D064249:Securin; D025801:Ubiquitin; C577674:fzr protein, Drosophila; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome