Abstract
The anaphase-promoting complex/cyclosome (APC/C) bound to CDC20 (APC/C(CDC20)) initiates anaphase by ubiquitylating B-type cyclins and securin. During chromosome bi-orientation, CDC20 assembles with MAD2, BUBR1 and BUB3 into a mitotic checkpoint complex (MCC) that inhibits substrate recruitment to the APC/C. APC/C activation depends on MCC disassembly, which was proposed to require CDC20 autoubiquitylation. Here we characterize APC15, a human APC/C subunit related to yeast Mnd2. APC15 is located near APC/C's MCC binding site; it is required for APC/C-bound MCC (APC/C(MCC))-dependent CDC20 autoubiquitylation and degradation and for timely anaphase initiation but is dispensable for substrate ubiquitylation by APC/C(CDC20) and APC/C(CDH1). Our results support the model wherein MCC is continuously assembled and disassembled to enable rapid activation of APC/C(CDC20) and CDC20 autoubiquitylation promotes MCC disassembly. We propose that APC15 and Mnd2 negatively regulate APC/C coactivators and report generation of recombinant human APC/C.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Anaphase-Promoting Complex-Cyclosome
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Calcium-Binding Proteins / metabolism
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Cdc20 Proteins
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / metabolism*
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HeLa Cells
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Humans
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Immunoprecipitation
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M Phase Cell Cycle Checkpoints / genetics
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M Phase Cell Cycle Checkpoints / physiology*
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Mad2 Proteins
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Microscopy, Electron
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Microscopy, Fluorescence
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Models, Biological*
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Poly-ADP-Ribose Binding Proteins
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Protein Serine-Threonine Kinases / metabolism
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RNA Interference
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RNA, Small Interfering / genetics
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Repressor Proteins / metabolism
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Time-Lapse Imaging
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Ubiquitin-Protein Ligase Complexes / metabolism*
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Ubiquitin-Protein Ligases
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Ubiquitination
Substances
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ANAPC15 protein, human
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BUB3 protein, human
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Calcium-Binding Proteins
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Cdc20 Proteins
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Cell Cycle Proteins
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MAD2L1 protein, human
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Mad2 Proteins
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Poly-ADP-Ribose Binding Proteins
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RNA, Small Interfering
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Repressor Proteins
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CDC20 protein, human
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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Ubiquitin-Protein Ligases
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BUB1 protein, human
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Bub1 spindle checkpoint protein
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Protein Serine-Threonine Kinases