title: Activation of the human anaphase-promoting complex by proteins of the CDC20/Fizzy family.
abstract: The initiation of anaphase and exit from mitosis depend on the activation of the cyclosome/anaphase-promoting complex (APC) that ubiquitinates regulatory proteins such as anaphase inhibitors and mitotic cyclins [1-4]. Genetic experiments have demonstrated that two related WD40-repeat proteins--called Cdc20p and Hct1p/Cdh1p in budding yeast and Fizzy and Fizzy-related in Drosophila--are essential for APC--dependent proteolysis [5-11]. Human orthologs of these proteins--hCDC20/p55CDC [12] and hCDH1--have recently been found to associate with APC in a cell-cycle-dependent manner [13,14]. Here, we show that the amount of hCDC20 and hCDH1 bound to APC correlates with a high ubiquitination activity of APC and that binding of recombinant hCDC20 and hCDH1 can activate APC in vitro. Our results suggest that the association between hCDH1 and APC is regulated by post-translational mechanisms, whereas the amount of hCDC20 bound to APC may in addition be controlled by hCDC20 synthesis and destruction [15]. The temporally distinct association of hCDC20 and hCDH1 with APC suggests that these proteins are, respectively, mitosis-specific and G1-specific activating subunits of APC.
authors.affiliation: Research Institute of Molecular Pathology (IMP), Vienna, Austria.
authors.forename: E R
authors.initials: ER
authors.lastname: Kramer
authors.forename: C
authors.initials: C
authors.lastname: Gieffers
authors.forename: G
authors.initials: G
authors.lastname: Hölzl
authors.forename: M
authors.initials: M
authors.lastname: Hengstschläger
authors.forename: J M
authors.initials: JM
authors.lastname: Peters
mesh_terms: D064173:Anaphase-Promoting Complex-Cyclosome; D000818:Animals; D064199:Cdc20 Proteins; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D004789:Enzyme Activation; D006367:HeLa Cells; D006801:Humans; D008025:Ligases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases; D014981:Xenopus; D029867:Xenopus Proteins
chemical_list: C577495:CDC20 protein, S cerevisiae; D064199:Cdc20 Proteins; C577501:Cdc20 protein, Xenopus; D018797:Cell Cycle Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D029867:Xenopus Proteins; C577488:CDC20 protein, human; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D044767:Ubiquitin-Protein Ligases; D008025:Ligases