Abstract
The anaphase-promoting complex/cyclosome (APC/C) is a conserved multisubunit ubiquitin ligase required for the degradation of key cell cycle regulators. The APC/C becomes active at the metaphase/anaphase transition and remains active during G(1) phase. One mechanism linked to activation of the APC/C is phosphorylation. Although many sites of mitotic phosphorylation have been identified in core components of the APC/C, the consequence of any individual phosphorylation event has not been elucidated in vivo. In this study, we show that Hcn1 is an essential core component of the fission yeast APC/C and is critical for maintaining complex integrity. Moreover, Hcn1 is a phosphoprotein in vivo. Phosphorylation of Hcn1 occurs at a single Cdk1 site in vitro and in vivo. Mutation of this site to alanine, but not aspartic acid, compromises APC/C function and leads to a specific defect in the completion of cell division.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Alanine / metabolism
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Amino Acid Substitution
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Anaphase-Promoting Complex-Cyclosome
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Cell Cycle Proteins / genetics
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Fungal Proteins / chemistry
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Fungal Proteins / genetics
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Fungal Proteins / metabolism*
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G2 Phase
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Gene Deletion
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Green Fluorescent Proteins / metabolism
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Phosphorylation
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Repressor Proteins / chemistry
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
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Schizosaccharomyces / cytology
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism*
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Schizosaccharomyces pombe Proteins / chemistry
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Schizosaccharomyces pombe Proteins / genetics
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Schizosaccharomyces pombe Proteins / metabolism*
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Ubiquitin-Protein Ligase Complexes / physiology*
Substances
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Cell Cycle Proteins
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Fungal Proteins
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Repressor Proteins
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Schizosaccharomyces pombe Proteins
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hcn1 protein, S pombe
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Green Fluorescent Proteins
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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Alanine